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Term pack

Year 9 Science

Name: ________________________

Skills in this pack

  • The cell and what is inside it
  • Plant and animal tissues
  • Diversity and classification
  • Reproduction: how life continues
  • Inside the atom
  • How atoms combine, and what a molecule weighs
  • Mixtures, concentration and separation
  • Sound waves
  • Work, energy and power

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Year 9 Science · 1 of 9

The cell and what is inside it

Name the parts of a plant and an animal cell and say what each does, tell a prokaryotic cell from a eukaryotic one, and use osmosis to explain what happens to a cell in salty water.

Before you start

The parts of a cell, each one named.

1234
  1. 1. The round body with a smaller body inside it — the nucleus
  2. 2. The rod with folded lines inside — a mitochondrion
  3. 3. The large clear space — the vacuole
  4. 4. The stack of folded sheets — the endoplasmic reticulum

The outline round the whole thing is the cell membrane. On a plant cell there would be a stiffer layer of cellulose outside it again, and green ovals of chloroplast among the organelles.

  1. 1.What is the one-word name for the movement of water across a selectively permeable membrane?

  2. 2.Match each organelle to the job it does in the cell.

    • Ribosome
    • Golgi apparatus
    • Lysosome
    • Mitochondrion
    • Chloroplast
    • Releasing the energy a cell runs on
    • Breaking down waste and worn-out parts
    • Where proteins are made
    • Making food using sunlight
    • Packing materials into vesicles for transport

  3. 3.Tap the part of this cell that holds the chromosomes.

    Write the number of the part.

    1234

  4. 4.A Rhoeo leaf peel is mounted in a strong sugar solution. Its cells lose water, yet the outline of each cell stays the same shape. What accounts for that?

    • a) The vacuole refills from the sugar solution as fast as water leaves
    • b) The rigid cell wall holds the outer shape while the membrane pulls inwards
    • c) Plant cells cannot lose water through their membranes
    • d) The chloroplasts stiffen and hold the cell out

  5. 5.Put the journey of a protein that is going to be secreted into order, starting from A ribosome on the rough endoplasmic reticulum makes the protein.

    • The Golgi apparatus packs it into a vesicle
    • The Golgi apparatus modifies and sorts it
    • A ribosome on the rough endoplasmic reticulum makes the protein
    • The vesicle carries it out to the cell membrane
    • The rough endoplasmic reticulum passes it on

  6. 6.A piece of potato is left in a 20 per cent salt solution for an hour. What happens to it, and why?

    • a) It shrinks, because salt is drawn out of the cells into the water
    • b) Nothing changes, because the membrane blocks both water and salt
    • c) It swells, because salt is drawn into the cells from the solution
    • d) It shrinks, because water leaves the cells for the more concentrated solution

  7. 7.Where in the body does meiosis take place, and what does it produce?

    • a) In the cells of the reproductive organs, producing two identical cells
    • b) In the cells of the reproductive organs, producing four cells with half the chromosome number
    • c) In the cells of the skin, producing two identical cells
    • d) Throughout the body, producing four cells with the full chromosome number

  8. 8.Sort each feature by the kind of cell it belongs to.

    Groups: Prokaryotic cell · Eukaryotic cell

    • Membrane-bound organelles
    • A typical width of 1 to 10 micrometres
    • A typical width of 10 to 100 micrometres
    • Genetic material in a bare nucleoid
    • Membrane-bound nucleus

The cell and what is inside it · Year 9 Science · www.arenapublications.com/learn

Year 9 Science · 2 of 9

Plant and animal tissues

Name the three meristems and the permanent tissues they become, match each plant and animal tissue to its job, and tell the joints and muscle types apart by what they do.

Before you start

Three simple permanent tissues, side by side and each one named.

123
  1. 1. Thin walls the whole way round — parenchyma
  2. 2. Corners thickened with pectin — collenchyma
  3. 3. Thick lignified walls — sclerenchyma

Parenchyma is alive and stores food. Collenchyma is alive and bends. Sclerenchyma is mostly dead cells, and it is what makes a coconut husk hard.

  1. 1.Match each plant tissue to the job it does.

    • Xylem
    • Phloem
    • Epidermis
    • Sclerenchyma
    • Collenchyma
    • Forms the outer protective layer
    • Supports a part while letting it bend
    • Carries water and minerals up from the roots
    • Carries food from the leaves to the rest of the plant
    • Makes a part hard and strong with lignified walls

  2. 2.How many pairs of ribs make up the human rib cage? Answer with a number.

  3. 3.Which iron-rich protein in the red blood cells gives blood its colour? Give the one word.

  4. 4.Bone and cartilage are both connective tissues. What makes one hard and the other springy?

    • a) Bone has a rigid matrix with calcium and phosphorus compounds; cartilage's matrix is soft and jelly-like
    • b) Bone has living cells and cartilage has none
    • c) Cartilage is a kind of muscle rather than a connective tissue
    • d) Cartilage has a rigid matrix and bone has a jelly-like one

  5. 5.Which muscle type has branched cylindrical fibres with a single nucleus and faint striations?

    • a) Skeletal muscle
    • b) Cardiac muscle
    • c) Smooth muscle
    • d) Epithelial muscle

  6. 6.Put a message's journey through a neuron in order, starting from The dendrites pick the message up from another neuron.

    • The cell body, which holds the nucleus, takes it in
    • The axon carries it away as a long fibre
    • The axon terminals pass it on to the next cell
    • The dendrites pick the message up from another neuron

  7. 7.What does a ligament join?

    • a) A nerve to a muscle
    • b) A muscle to a bone
    • c) One bone to another bone
    • d) A muscle to another muscle

  8. 8.What are the pores in a leaf's epidermis called? Give the one word.

Plant and animal tissues · Year 9 Science · www.arenapublications.com/learn

Year 9 Science · 3 of 9

Diversity and classification

Place an organism in one of the five kingdoms, run the hierarchy from kingdom down to species, and read and write a scientific name in the binomial system.

Before you start

The seven bands of the classification pyramid, each one named.

1234567
  1. 1. Kingdom, the broadest group of the seven
  2. 2. Phylum
  3. 3. Class
  4. 4. Order
  5. 5. Family
  6. 6. Genus
  7. 7. Species, the narrowest group of the seven

Each band sits inside the one above it, and the organisms in it share more features than the organisms in the band above. It works like an address, narrowing from country down to house.

  1. 1.Sort each organism into its kingdom.

    Groups: Monera · Protista · Fungi · Plantae

    • Mushroom
    • Paramecium
    • Amoeba
    • Cyanobacteria
    • Yeast
    • Spirogyra

  2. 2.Match each kingdom to what defines it.

    • Monera
    • Protista
    • Fungi
    • Plantae
    • Animalia
    • Multicellular eukaryotes without cell walls that feed on other organisms
    • Prokaryotes, whose nucleus has no membrane around it
    • Eukaryotes with chitin cell walls that feed on dead matter
    • Single-celled eukaryotes
    • Multicellular eukaryotes with cellulose cell walls that make their own food

  3. 3.Why does the chapter say classification is worth the trouble?

    • a) There are millions of organisms, and a system makes any of them findable and comparable
    • b) It reduces the number of species that scientists have to study
    • c) It gives each organism a name in the language of the country it lives in
    • d) It fixes the number of kingdoms once and for good

  4. 4.A geologist digs down through undisturbed rock layers. What does the chapter say she will generally find as she goes deeper?

    • a) The same organisms at each depth
    • b) Fossils of simpler organisms
    • c) No fossils at any depth
    • d) Fossils of more complex organisms

  5. 5.Which of these is written according to the rules for a scientific name?

    • a) panthera Tigris, in italics
    • b) PANTHERA TIGRIS, in italics
    • c) Panthera tigris, in italics
    • d) Tigris panthera, in italics

  6. 6.Amoeba, Paramecium and Euglena are grouped together. What do they have in common that puts them in one kingdom?

    • a) They are prokaryotes with no true nucleus
    • b) They have cell walls made of chitin
    • c) They are single-celled eukaryotes living in water or moist places
    • d) They are multicellular and make their own food

  7. 7.Yeast is a single-celled organism, yet it is not placed in Protista. Why is it in Fungi?

    • a) It is multicellular under the microscope
    • b) Its cell wall is made of chitin
    • c) It makes its own food by photosynthesis
    • d) It is a prokaryote

  8. 8.A mango tree's scientific name has two words: Mangifera comes first. Which of the two words names the species? Write it.

Diversity and classification · Year 9 Science · www.arenapublications.com/learn

Year 9 Science · 4 of 9

Reproduction: how life continues

Tell asexual reproduction from sexual, name the parts of a flower and follow pollen through to a seed, and describe fertilisation and the reproductive cycle in animals and humans.

Before you start

The parts of a flower, each one named.

123456
  1. 1. The green flap at the base — a sepal
  2. 2. The broad flap sweeping out to the side — a petal
  3. 3. The small sac on the end of the slender stalk — the anther of a stamen
  4. 4. The flattened cap on top of the central column — the stigma
  5. 5. The thin central column — the style
  6. 6. The rounded swelling at the base of the column — the ovary

Sepals and petals are the two outer whorls. The stamen is the male part and the pistil — stigma, style and ovary together — is the female one.

  1. 1.What is a fertilised egg called? Give the one word.

  2. 2.How many parts does a complete flower have? Answer with a number.

  3. 3.A gardener grows twenty plants from cuttings of one rose bush. How do the new plants compare with the parent?

    • a) They are identical to each other but different from the parent
    • b) They vary from it, because cuttings mix genetic material from two parents
    • c) They are genetically identical to it, because one parent and mitosis were involved
    • d) They vary, because meiosis takes place when a cutting roots

  4. 4.What is the one-word name for the transfer of pollen grains from a stamen to a stigma?

  5. 5.Match each part of a flower to what it does.

    • Anther
    • Stigma
    • Style
    • Ovary
    • Sepal
    • Receives the pollen
    • Protects the flower while it is in bud
    • Holds the ovules and becomes the fruit
    • Connects the stigma down to the ovary
    • Produces the pollen grains

  6. 6.Sort each case by the kind of reproduction it is.

    Groups: Asexual reproduction · Sexual reproduction

    • A Bryophyllum leaf sprouting tiny plantlets
    • A gardener rooting a sugarcane stem cutting
    • A male gamete from a pollen grain fusing with an egg cell
    • A frog releasing eggs into water for a male to fertilise
    • A potato sprouting new plants from its underground stem

  7. 7.A frog lays thousands of eggs in a pond while a bird lays a handful in a nest. What does the chapter say about the two strategies?

    • a) The frog's fertilisation is external and survival is low; the bird's is internal and survival is better
    • b) Survival is the same in both; the frog simply lays more
    • c) The frog's fertilisation is internal and the bird's external
    • d) Both fertilise internally, and the difference lies in nest-building

  8. 8.Put the journey from pollination to seed in order, starting from Pollen lands on a stigma it is compatible with.

    • The male gamete travels down the tube to the ovule
    • Pollen lands on a stigma it is compatible with
    • The ovule becomes a seed while the ovary swells into a fruit
    • The pollen grain grows a pollen tube down through the style
    • It fuses with the egg cell, and the fertilised egg is a zygote

Reproduction: how life continues · Year 9 Science · www.arenapublications.com/learn

Year 9 Science · 5 of 9

Inside the atom

Count protons, neutrons and electrons from an atomic number and a mass number, fill the shells and read off a valency, and say what makes two atoms isotopes.

Before you start

The parts of an atom, each one named.

1234
  1. 1. The centre
  2. 2. The nearest ring
  3. 3. The middle ring
  4. 4. The furthest ring

The centre is the nucleus, holding the protons and neutrons. The rings are the shells, filled from the inside out: K first, then L, then M.

  1. 1.Oxygen's electronic configuration is 2, 6. What is its valency? Answer with a number.

  2. 2.Nitrogen's electronic configuration is 2, 5. What is its valency? Answer with a number.

  3. 3.Sort each subatomic particle by the charge it carries.

    Groups: Positive charge · Negative charge · No charge

    • Proton
    • Electron
    • Neutron

  4. 4.An atom of atomic number 26 has 56 nucleons. How many neutrons has it? Answer with a number.

  5. 5.Hydrogen occurs as three isotopes. Which one has two neutrons?

    • a) Deuterium
    • b) Protium
    • c) Tritium
    • d) Each of the three has two

  6. 6.Why do the isotopes of an element behave the same way chemically?

    • a) They have the same melting and boiling points
    • b) They have the same number of electrons, arranged the same way
    • c) They have the same mass number
    • d) They have the same number of neutrons

  7. 7.An atom's outermost shell holds 8 electrons. What does the chapter say to expect of it?

    • a) It reacts readily, needing to shed its eight
    • b) It has a valency of eight
    • c) It is largely unreactive, its octet being complete
    • d) It reacts readily, needing to gain eight more

  8. 8.Two atoms have the same atomic number but different mass numbers. What are they called?

    • a) Two molecules of one compound
    • b) Ions of the same element
    • c) Isotopes of the same element
    • d) Two different elements

Inside the atom · Year 9 Science · www.arenapublications.com/learn

Year 9 Science · 6 of 9

How atoms combine, and what a molecule weighs

Use the laws of conservation of mass and of constant proportions, tell a covalent bond from an ionic one, write a formula by crossing over valencies, and add up a molecular or formula unit mass.

Before you start

A sodium atom beside a chlorine atom, with each shell named.

1234
  1. 1. Sodium's inner shells, holding 2 then 8 electrons
  2. 2. Sodium's valence shell, holding its single electron
  3. 3. Chlorine's inner shells, holding 2 then 8 electrons
  4. 4. Chlorine's valence shell, holding 7 electrons

Sodium has one electron more than a full inner arrangement; chlorine is one short of eight. Hand the electron across and both are satisfied — that is an ionic bond in one move.

  1. 1.Why is sodium chloride described by a formula unit mass rather than a molecular mass?

    • a) Its ions form a crystal rather than separate molecules
    • b) It is too heavy for a molecular mass to be worked out
    • c) Its atoms share electrons instead of transferring them
    • d) Its formula has more than one kind of atom in it

  2. 2.Sodium and chlorine combine in the mass ratio 23 to 35.5. If 46 g of sodium reacts completely, what mass of chlorine is needed, in g? Answer with a number.

  3. 3.A sodium atom, with 11 protons and 11 electrons, loses its single valence electron. What is it now?

    • a) Still a neutral atom, since electrons carry no charge
    • b) A different element, since its proton count changed
    • c) A cation, carrying one positive charge
    • d) An anion, carrying one negative charge

  4. 4.Sort each substance by the kind of bond holding it together.

    Groups: Held together by sharing electrons · Held together by transferring electrons

    • Chlorine molecule
    • Sodium chloride
    • Hydrogen molecule
    • Magnesium oxide

  5. 5.Taking K as 39 u and Cl as 35.5 u, what is the formula unit mass of potassium chloride, KCl, in u? Answer with a number.

  6. 6.Put the steps for writing a covalent compound's formula in order, starting from Write the symbols of the elements in the compound.

    • Write each element's valency below its symbol
    • Write them as subscripts, leaving out a subscript of one
    • Cross the valencies over to the other symbol
    • Write the symbols of the elements in the compound

  7. 7.Which of these describes a molecule, as the chapter defines it?

    • a) A charged particle formed when an atom gains an electron
    • b) The simplest whole-number ratio of ions in a crystal
    • c) A single atom of any element
    • d) An electrically neutral group of more than one atom that can exist on its own

  8. 8.Taking C as 12 u and H as 1 u, what is the molecular mass of methane, CH4, in u? Answer with a number.

How atoms combine, and what a molecule weighs · Year 9 Science · www.arenapublications.com/learn

Year 9 Science · 7 of 9

Mixtures, concentration and separation

Tell solutions, suspensions and colloids apart, work out a concentration as a percentage, and choose the right method for pulling a given mixture apart.

Before you start

Three beakers, and what the laser beam does in each of them.

123
  1. 1. Salt in water — the beam crosses unseen
  2. 2. Chalk powder in water — the beam shows, and the powder settles
  3. 3. Milk in water — the beam shows, and nothing settles

Shine the light in from the side and watch from a right angle. The path you can see is light being scattered off particles big enough to scatter it.

  1. 1.Match each separation method to the mixture it is meant for.

    • Distillation
    • Separating funnel
    • Sublimation
    • Paper chromatography
    • Centrifugation
    • A solid that sublimes mixed with one that does not
    • The coloured components of an ink or a dye
    • Two immiscible liquids
    • Two miscible liquids with different boiling points
    • Heavier particles from a lighter liquid

  2. 2.25 mL of juice concentrate is made up with water to 250 mL of drink. What is the volume by volume percentage of concentrate? Answer with a number.

  3. 3.A black ink spot is put on a paper strip and the strip is dipped so the water level starts below the spot. The water rises and the spot spreads into several coloured bands. Why do the bands separate?

    • a) The heavier colours sink while the lighter ones rise
    • b) The components travel up the paper at different speeds
    • c) Water dissolves some colours and destroys the others
    • d) The paper reacts with each colour to make a new one

  4. 4.8 g of glucose is dissolved in water and made up to 200 mL of solution. What is the mass by volume percentage? Answer with a number.

  5. 5.A saturated solution of a solid is made at 60 °C and then cooled slowly to 40 °C. What happens?

    • a) Some of the solid separates out, because less of it can stay dissolved at the lower temperature
    • b) Nothing changes, because solubility does not depend on temperature
    • c) More of the solid dissolves, because cooling makes room for it
    • d) The solvent boils away and leaves the solid behind

  6. 6.20 g of sugar is dissolved in 80 g of water. What is the mass by mass percentage of the solution? Answer with a number.

  7. 7.A mixture of crushed camphor and sand is heated gently under an inverted funnel, and a white solid appears on the inside of the funnel. What has happened?

    • a) The camphor turned straight to vapour and then back to solid, while the sand stayed put
    • b) The two solids reacted to make a new white compound
    • c) The camphor melted, boiled and then condensed as a liquid
    • d) The sand melted and rose as a vapour, leaving the camphor behind

  8. 8.Put the steps of growing copper sulfate crystals in order, starting from Warm the water with the solid, stirring, until no more will dissolve.

    • Filter off the crystals and rinse them with cold water
    • Filter the hot saturated solution to take out insoluble impurities
    • Cover the filtrate and leave it to cool slowly, undisturbed
    • Leave the crystals to dry on a watch glass
    • Warm the water with the solid, stirring, until no more will dissolve

Mixtures, concentration and separation · Year 9 Science · www.arenapublications.com/learn

Year 9 Science · 8 of 9

Sound waves

Say why sound needs a medium, use v = λν and ν = 1/T, work out an echo distance, and place a frequency in the infrasonic, audible or ultrasonic band.

Before you start

Two sound waves, drawn one above the other.

12
  1. 1. The quieter wave — a small change in density, so less energy
  2. 2. The louder wave — a large change in density, so more energy

The two waves rise and fall the same number of times across the page, so they share a wavelength and a frequency. What differs is how far the density swings from its average — the amplitude.

  1. 1.A sound wave is drawn as density against distance, with the middle line marking the average density. Tap the span that is one wavelength.

    Write the number of the part.

    123

  2. 2.A wave has a time period of 0.02 s. What is its frequency, in Hz? Answer with a number.

  3. 3.A point in a medium goes through 10 density oscillations in 4 s. What is the frequency of the wave, in Hz? Answer with a number.

  4. 4.You clap and hear the echo 0.6 s later. Taking the speed of sound as 340 m/s, how far away is the reflecting wall, in m? Answer with a number.

  5. 5.Sound travels at 340 m/s. What is the wavelength of a note of frequency 850 Hz, in m? Answer with a number.

  6. 6.A sound wave has a wavelength of 0.5 m and a frequency of 600 Hz. What is its speed, in m/s? Answer with a number.

  7. 7.In a large hall a sound seems to hang in the air after the speaker has stopped. What is that called, and what causes it?

    • a) An echo, from a single reflection arriving more than 0.1 s later
    • b) Reverberation, from repeated reflections arriving less than 0.05 s apart
    • c) Resonance, from the hall matching the speaker's frequency
    • d) Refraction, from the sound bending round the pillars

  8. 8.A metal plate is struck harder than before. What changes in the sound wave it sends out?

    • a) Its speed is greater, so it carries more energy
    • b) Its amplitude is larger, so it carries more energy
    • c) Its time period is longer, so it carries more energy
    • d) Its wavelength is larger, so it carries more energy

Sound waves · Year 9 Science · www.arenapublications.com/learn

Year 9 Science · 9 of 9

Work, energy and power

Work out work done, kinetic energy, potential energy and power, say when work is positive, negative or zero, and explain what a pulley, a ramp and a lever actually change.

Before you start

The parts of a lever, each one named.

1234
  1. 1. The load, the weight to be lifted
  2. 2. The fulcrum, the fixed point the bar turns about
  3. 3. The effort, the push you apply
  4. 4. The load arm, from the load to the fulcrum

Put the fulcrum close to the load and the effort arm becomes long. A small push over a long distance then lifts a large load through a short one.

  1. 1.Sort each case by the work the named force does on the named object.

    Groups: Positive work done on the object · Negative work done on the object · No work done on the object

    • A goalkeeper stopping a moving ball
    • Friction acting on a sliding stack of coins
    • A girl slowly lowering a dumbbell
    • A person pushing hard on a rigid wall
    • A boy pushing a wheelchair forward

  2. 2.Three simple machines are sketched below. Tap the one that changes the direction of the force you apply without reducing how large it has to be.

    Write the number of the part.

    123

  3. 3.A vehicle's speed doubles. What happens to its kinetic energy?

    • a) It becomes four times as large
    • b) It becomes twice as large
    • c) It stays the same
    • d) It becomes eight times as large

  4. 4.A book of mass 2 kg is raised 1.5 m above the floor. Taking g as 10 m/s², what is its potential energy, in J? Answer with a number.

  5. 5.A force of 25 N moves a crate 4 m along the direction of the force. How much work is done on the crate, in J? Answer with a number.

  6. 6.Match each form of energy to what it is.

    • Mechanical energy
    • Thermal energy
    • Chemical energy
    • Nuclear energy
    • Electrical energy
    • Energy an object has from its motion or its position
    • Energy stored in the nuclei of atoms
    • Energy that makes things warm or hot
    • Energy stored in fuels and food in the bonds between atoms
    • Energy to do with the position or the motion of charges

  7. 7.A machine raises a load of 300 N when an effort of 100 N is applied. What is its mechanical advantage? Answer with a number.

  8. 8.A stone is dropped from a height and falls freely. What happens to its mechanical energy on the way down?

    • a) It becomes zero the moment the stone starts moving
    • b) It stays the same, as potential energy turns into kinetic energy
    • c) It falls, because the stone loses height
    • d) It rises, because the stone speeds up

Work, energy and power · Year 9 Science · www.arenapublications.com/learn

Answer keys — Year 9 Science

In the same order as the worksheets.

The cell and what is inside it

  1. 1. osmosis
  2. 2. Ribosome → Where proteins are made; Golgi apparatus → Packing materials into vesicles for transport; Lysosome → Breaking down waste and worn-out parts; Mitochondrion → Releasing the energy a cell runs on; Chloroplast → Making food using sunlight
  3. 3. 1 — The round body with a smaller body inside it
  4. 4. b) The rigid cell wall holds the outer shape while the membrane pulls inwards
  5. 5. 1. A ribosome on the rough endoplasmic reticulum makes the protein 2. The rough endoplasmic reticulum passes it on 3. The Golgi apparatus modifies and sorts it 4. The Golgi apparatus packs it into a vesicle 5. The vesicle carries it out to the cell membrane
  6. 6. d) It shrinks, because water leaves the cells for the more concentrated solution
  7. 7. b) In the cells of the reproductive organs, producing four cells with half the chromosome number
  8. 8. Genetic material in a bare nucleoid → Prokaryotic cell; A typical width of 1 to 10 micrometres → Prokaryotic cell; Membrane-bound organelles → Eukaryotic cell; Membrane-bound nucleus → Eukaryotic cell; A typical width of 10 to 100 micrometres → Eukaryotic cell

Plant and animal tissues

  1. 1. Xylem → Carries water and minerals up from the roots; Phloem → Carries food from the leaves to the rest of the plant; Epidermis → Forms the outer protective layer; Sclerenchyma → Makes a part hard and strong with lignified walls; Collenchyma → Supports a part while letting it bend
  2. 2. 12
  3. 3. haemoglobin
  4. 4. a) Bone has a rigid matrix with calcium and phosphorus compounds; cartilage's matrix is soft and jelly-like
  5. 5. b) Cardiac muscle
  6. 6. 1. The dendrites pick the message up from another neuron 2. The cell body, which holds the nucleus, takes it in 3. The axon carries it away as a long fibre 4. The axon terminals pass it on to the next cell
  7. 7. c) One bone to another bone
  8. 8. stomata

Diversity and classification

  1. 1. Cyanobacteria → Monera; Amoeba → Protista; Paramecium → Protista; Yeast → Fungi; Mushroom → Fungi; Spirogyra → Plantae
  2. 2. Monera → Prokaryotes, whose nucleus has no membrane around it; Protista → Single-celled eukaryotes; Fungi → Eukaryotes with chitin cell walls that feed on dead matter; Plantae → Multicellular eukaryotes with cellulose cell walls that make their own food; Animalia → Multicellular eukaryotes without cell walls that feed on other organisms
  3. 3. a) There are millions of organisms, and a system makes any of them findable and comparable
  4. 4. b) Fossils of simpler organisms
  5. 5. c) Panthera tigris, in italics
  6. 6. c) They are single-celled eukaryotes living in water or moist places
  7. 7. b) Its cell wall is made of chitin
  8. 8. indica

Reproduction: how life continues

  1. 1. zygote
  2. 2. 4
  3. 3. c) They are genetically identical to it, because one parent and mitosis were involved
  4. 4. pollination
  5. 5. Anther → Produces the pollen grains; Stigma → Receives the pollen; Style → Connects the stigma down to the ovary; Ovary → Holds the ovules and becomes the fruit; Sepal → Protects the flower while it is in bud
  6. 6. A potato sprouting new plants from its underground stem → Asexual reproduction; A Bryophyllum leaf sprouting tiny plantlets → Asexual reproduction; A gardener rooting a sugarcane stem cutting → Asexual reproduction; A male gamete from a pollen grain fusing with an egg cell → Sexual reproduction; A frog releasing eggs into water for a male to fertilise → Sexual reproduction
  7. 7. a) The frog's fertilisation is external and survival is low; the bird's is internal and survival is better
  8. 8. 1. Pollen lands on a stigma it is compatible with 2. The pollen grain grows a pollen tube down through the style 3. The male gamete travels down the tube to the ovule 4. It fuses with the egg cell, and the fertilised egg is a zygote 5. The ovule becomes a seed while the ovary swells into a fruit

Inside the atom

  1. 1. 2
  2. 2. 3
  3. 3. Proton → Positive charge; Electron → Negative charge; Neutron → No charge
  4. 4. 30
  5. 5. c) Tritium
  6. 6. b) They have the same number of electrons, arranged the same way
  7. 7. c) It is largely unreactive, its octet being complete
  8. 8. c) Isotopes of the same element

How atoms combine, and what a molecule weighs

  1. 1. a) Its ions form a crystal rather than separate molecules
  2. 2. 71
  3. 3. c) A cation, carrying one positive charge
  4. 4. Hydrogen molecule → Held together by sharing electrons; Chlorine molecule → Held together by sharing electrons; Sodium chloride → Held together by transferring electrons; Magnesium oxide → Held together by transferring electrons
  5. 5. 74.5
  6. 6. 1. Write the symbols of the elements in the compound 2. Write each element's valency below its symbol 3. Cross the valencies over to the other symbol 4. Write them as subscripts, leaving out a subscript of one
  7. 7. d) An electrically neutral group of more than one atom that can exist on its own
  8. 8. 16

Mixtures, concentration and separation

  1. 1. Distillation → Two miscible liquids with different boiling points; Separating funnel → Two immiscible liquids; Sublimation → A solid that sublimes mixed with one that does not; Paper chromatography → The coloured components of an ink or a dye; Centrifugation → Heavier particles from a lighter liquid
  2. 2. 10
  3. 3. b) The components travel up the paper at different speeds
  4. 4. 4
  5. 5. a) Some of the solid separates out, because less of it can stay dissolved at the lower temperature
  6. 6. 20
  7. 7. a) The camphor turned straight to vapour and then back to solid, while the sand stayed put
  8. 8. 1. Warm the water with the solid, stirring, until no more will dissolve 2. Filter the hot saturated solution to take out insoluble impurities 3. Cover the filtrate and leave it to cool slowly, undisturbed 4. Filter off the crystals and rinse them with cold water 5. Leave the crystals to dry on a watch glass

Sound waves

  1. 1. 1 — The span from one crest across to the next crest
  2. 2. 50
  3. 3. 2.5
  4. 4. 102
  5. 5. 0.4
  6. 6. 300
  7. 7. b) Reverberation, from repeated reflections arriving less than 0.05 s apart
  8. 8. b) Its amplitude is larger, so it carries more energy

Work, energy and power

  1. 1. A boy pushing a wheelchair forward → Positive work done on the object; A goalkeeper stopping a moving ball → Negative work done on the object; Friction acting on a sliding stack of coins → Negative work done on the object; A girl slowly lowering a dumbbell → Negative work done on the object; A person pushing hard on a rigid wall → No work done on the object
  2. 2. 1 — A wheel with a rope over it
  3. 3. a) It becomes four times as large
  4. 4. 30
  5. 5. 100
  6. 6. Mechanical energy → Energy an object has from its motion or its position; Thermal energy → Energy that makes things warm or hot; Chemical energy → Energy stored in fuels and food in the bonds between atoms; Nuclear energy → Energy stored in the nuclei of atoms; Electrical energy → Energy to do with the position or the motion of charges
  7. 7. 3
  8. 8. b) It stays the same, as potential energy turns into kinetic energy

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