Unit 0 - Basic Skills

Question 1

List and describe the characteristics of living organisms

Answer 1

Movement - ability to move
Respiration - organisms taking in oxygen and giving out carbon dioxide. The release of energy from the chemical breakdown of glucose. Glucose reacts with O2 to make ATP.
Sensitivity - can sense the organism’s surroundings.
Circulation - Able to move food, gasses, and wastes around their body. eg circulation of blood
Growth - Getting bigger (more matter)
Reproduction - cells and offspring
Excretion - getting rid of waste products
Nutrition - need nutrition to function.

Question 2

What are living organisms made of?

Answer 2

Cells

Question 3

Draw and describe the structure of a palisade cell and an animal cell (liver) as seen under a light microscope

Answer 3

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Question 4

Describe functions of structures of palisade and liver cell as seen under a microscope.

Answer 4

Palisade:
Cell wall - strengthens the cell. Helps the plant stay stiff. Turgid.
*Cell membrane - controls the entry and exit of chemicals into the cell.
Nucleus - contains genetic material which controls the cell’s activities
Chloroplast - contains chlorophyll which absorbs light energy for photosynthesis
()Vacuoles - contains chemicals/liquid.
*Cytoplasm - Most chemical reactions take place here, controlled by enzymes. Stores organelles.
*Mitochondria - most energy is released by respiration here.

Liver cell:
Ribosome - protein synthesis happens here.
Parts with an * is also present in animal cells.

Question 5

How to calculate magnification and size of specimens using millimetres as units

Answer 5

Magnification = eyepiece x * lens x
eg eyepiece = 10x, lens = 40x, total magnification = 400x

Size of real specimen = measured length / magnification
eg measured specimen = 260mm = 260,000 um.
260,000 / 900 = 2888.89 um

um = micrometre

Question 6

List the chemical elements that make up carbohydrates, fats and proteins

Answer 6

Carbohydrates = hydrogen, carbon and oxygen
Fats = hydrogen, carbon, oxygen. Same as carbohydrates
Proteins = Nitrogen. Some may contain sulphur.

Question 7

Describe the structure of large molecules made from smaller basic units

Answer 7

Simple sugars to starch and glycogen
Amino acids to proteins
Fatty acids and glycerol to fats and oils

Question 8

Describe tests for starch, reducing sugars, protein and fats

Answer 8

Starch - add iodine. Positive = turns purple/black

Reducing sugars - Benedict’s solution. Blue -> orange/green/red.

Protein - Biuret solution. Blue -> purple.

Fats - Sodium hydroxide and shake. Cloudy
suspension. Or smear on paper towel. Or add ethanol.

Question 9

List the principal sources of, and describe the importance of carbohydrates, fats, proteins, vitamins (C and D only), mineral salts (calcium and iron only), fibre (roughage), water.

Answer 9

Carbohydrates: Sugars (glucose, fructose), starches (potatoes, rice, bread), cellulose (vegetable, fruits, wood.
Supplies about 60% of our energy. Cannot be used by the body, helps food push through.
If we don’t get it: lack of energy, lose weight, body processes slow.

Fats: Oils, meat, dairy, nuts.
Stored by the body, they provide a store of energy. Supply about 25% of our energy. Insulation.
If we don’t get it: lose weight.

Proteins: Eggs, meat, fish.
Muscles and ligaments/tendons, Hair/skin are made of proteins. Supplies materials for muscles.
If we don’t get it: Bad hair/skin/injuries

Vitamin C: Citrus fruits.
For eyesight, skin, hair, immune system.

Vitamin D: Sunlight.
For enhancing absorption of calcium and phosphate.

Calcium: from cheese, milk, yoghurt.
For growth and maintenance of healthy teeth and bones.

Iron: liver, vegetables, blood.
To make blood.

Fibre: Vegetables, whole grains.
For healthy bowels.

Water: tap.
For body temperature regulation, cushions and lubricates joints, nourishes and protects the brain, removes waste through perspiration, bowel movements and regulation. Our bodies are composed mostly of water - about 60%.

Question 10

Describe the use of microorganisms in the manufacture of yoghurt.

Answer 10

The souring of milk is a fermentation process, as it takes place better when oxygen is absent. Fresh milk contains sugars and some bacteria. the bacteria feed on the sugars in the milk. The main sugar in milk is called lactose. Lactose is converted into lactic acid by bacterial fermentation, the increased acidity sours and thickens the milk.

Question 11

Describe the deficiency symptoms for vitamins C & D, mineral salts (calcium and iron)

Answer 11

Vitamin C:
Anemia (low red blood cell count). Easy fatigue and loss of energy, dizziness, shortness of breath.
Scurvy: general weakness, anemia, gum disease, skin haemorrhages.

Vitamin D: Soft bones (rickets). Bone pain and muscle weakness.

Calcium: Osteoporosis (fragile bones), rickets (softening of bones)

Iron: Anaemia (low red blood cell count). Tiredness and lack of energy.Dizziness. Coldness in hands and feet.

Question 12

Define “atom” and “molecule”

Answer 12

Atom: The smallest stable unit of matter.

Molecule: 2 or more atoms chemically joined together.

Question 13

State the distinguishing properties of solids, liquids and gases

Answer 13

Solids:
Particles are tightly packed, usually in a regular pattern.
Retains a fixed volume and shape (rigid particles locked into place)
Cannot be compressed
Does not flow easily (rigid particles can’t move/slide past one another)
Dense

Liquids:
Particles are close together with no regular arrangement.
Assumes shape of container (particles slide past one another)
Not easily compressible
Definite volume
Most liquids expand with an increase of temperature and constant air pressure
Dense

Gases:
Particles are well separated with no regular arrangement.
Assumes shape and volume of its container (particles have enough energy to overcome attractive forces)
The volume of a quantity of gas is dependent on its temperature and the surrounding pressure.
Compressible
Flows easily
Have no definite shape or volume
If unconstrained the gases will spread out indefinitely
Low density.

Question 14

Describe qualitatively the molecular structure of solids, liquids and gases.

Answer 14

Solids:
Closely packed. Regular pattern

Liquids:
Close together with no regular pattern

Gases:
Particles well separated with no regular arrangement

Question 15

Relate the properties of solids, liquids and gases to the forces and distances between molecules and to the motion of the molecules.

Answer 15

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Question 16

Describe the structure of an atom

Answer 16

A nucleus containing protons and neutrons surrounded by a cloud of electrons

Question 17

State the charges and masses of protons, neutrons and electrons

Answer 17

Protons: Positive. Heavy
Neutrons: Neutral. Heavy
Electrons: Negative. Light.

Question 18

Define PROTON NUMBER and NUCLEON NUMBER

Answer 18

Proton number: the number of protons in an atom

Nucleon number: the number of protons AND neutrons.

Question 19

Describe the build-up of electrons in “shells” and understand the significance of the noble gas electronic structures and of valence electrons

Answer 19

Electron arrangement:
1st shell: 2
2nd shell: 8 
3rd shell: 8
4th shell: an amount.

Nobel gases have a full outer electron shell so they do not react.

Valence shell: outermost shell

Question 20

Use the proton number and the simple structure of atoms to explain the layout of the periodic table with reference to the elements of proton number 1 to 20.

Answer 20

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Question 21

Identify physical and chemical changes, and understand the differences between them.

Answer 21

Physical - changes form but keeps its same chemical composition (reversible)

Chemical - when a substance’s composition has been changed.

Question 22

Difference between elements, compounds and mixtures

Answer 22

Elements only contain one type of atom and cannot be broken down into a simpler type of matter by either physical or chemical means and can exist as either atoms or molecules.

Compounds consist of two or more DIFFERENT elements bound together. Can be broken down into a simpler type of matter by chemical means. Has properties that are different from its component elements. Always contains the same ratio of its component elements.

Mixtures consist of two or more different elements and/or compounds PHYSICALLY mingled. Can be separated into its components by physical means and often retains many of the properties of its components. Eg powdered iron and powdered sulphur can be separated using a magnet.

Question 23

Describe methods of separation and purification: filtration, crystallisation, distillation, fractional distillation.

Answer 23

Filtration - separates insoluble solids from liquids
Crystallisation - copper sulfate. A saturated solution warmed and cooled so crystals will start to grow.
Distillation - removes souvent from solute, but then condenses it back into liquid.
Fractional distillation - Fractional distillation differs from distillation only in that it separates a mixture into a number of different parts, called fractions. A tall column is fitted above the mixture, with several condensers coming off at different heights. The column is hot at the bottom and cool at the top. Substances with high boiling points condense at the bottom and substances with low boiling points condense at the top. Like distillation, fractional distillation works because the different substances in the mixture have different boiling points.
Eg oil fractions

Question 24

Describe paper chromatography

Answer 24

Used to separate and identify components of a mixture. Identify colouring agents for example in food or ink.

Question 25

Interpret simple chromatograms

Answer 25

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Question 26

State that weight is a force

Answer 26

Weight is a force

Question 27

Know that the earth is the source of a gravitational field

Answer 27

The earth is the source of a gravitational field

Question 28

Know that force is measured in newtons (N)

Answer 28

Force is measured in Newtons (N)

Question 29

Describe, and use the concept of, weight as the effect of a gravitational field on a mass

Answer 29

Weight is the effect of a gravitational field on a mass

Question 30

Describe an experiment to determine the density of a liquid and of a regularly shape solid using the appropriate equation.

Answer 30

Density = mass/volume
D = m/v

Question 31

Describe the determination of the density of an irregularly shaped solid by the method of displacement, and make the necessary calculation

Answer 31

Put solid in measuring cylinder of water. The increased height/volume = volume of irregular solid.

Question 32

Describe how forces may change the size, shape and motion of a body

Answer 32

Force producing a change in state of motion gives a body acceleration. If forces acting on a body produces no acceleration, the body will experience some change in configuration: a change of size (longer or shorter), a change of shape (twisted or bent), or a positional change (relative to other masses, charges, or magnets). Changes of size or shape involve elastic properties of materials.

Question 33

Hooke’s Law

Answer 33

Force = constant x extension. 
F = kx

Question 34

Limit of proportionality

Answer 34

A graph of load against extension will be a straight line as long as the elastic limit is not exceeded - so the extension is proportional to the load - so as far as it goes the elastic limit is the limit of proportionality.

Question 35

Relate the properties of solids, liquids and gases to the forces and distances between the molecules and to the motion of the molecules

Answer 35

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Question 36

Interpret simple chromatograms

Answer 36

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Question 37

Plot and interpret extension/load graphs

Answer 37

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