Miscellaneous

Question 1

Snakes are predators that lay eggs. Scientists investigated courtship behaviour in male garter snakes in response to:l the body length of the femalel lipids secreted on the skin of the female.For each trial, the scientists selected 10 male snakes at random. They placed the snakes into a large cage. The scientists then placed one of the following into the cage with the male snakes:1. a short female snake2. a long female snake3. a piece of filter paper containing lipids from the skins of short females 4. a piece of filter paper containing lipids from the skins of long females.After 5 minutes, the scientists recorded how many males were showing courtship behaviour. Each trial was repeated several times using different male and female snakes.Apart from the size of the female, suggest two factors that should have been kept constant in order to obtain reliable results

Answer 1

Any two suitable suggestions eg1. Volume/concentration of skin lipid;2. Age/sexual maturity;3. Species of snake;4. Size of male;5. Colour;6. T emperature;7. Light;8. Time of day/year/breeding season;9. Duration/length of time observing;10. Diet;11. Filter paper;12. Size of cage;

Question 2

The male snakes used for each trial were selected at random. Explain why this was impor tant.

Answer 2

To avoid bias

Question 3

The scientists used different male snakes in each trial. Suggest why.

Answer 3

1. To avoid change in (courtship) behaviour (due to past experience)2. To observe a typical/general/representative (response);

Question 4

What should the scientists have placed in the cage as a control, to show that males were responding to lipids from females?

Answer 4

Filter paper without (skin) lipids / untreated filter paper / filter paper with water / (female) snakes with lipids removed

Question 5

Suggest two advantages of male snakes courting with longer females.

Answer 5

(Parent/offspring)1. Produce more/larger offspring/eggs;2. Better predators / fitter / more successful at gaining food / less likely to be eaten / more able to protect offspring/eggs;3. (More) sexually mature / fertile;4. Have more food stores for offspring/eggs;

Question 6

Name the type of reaction that would break down starch glycogen and cellulose into their monomers.

Answer 6

HYDROLYSIS

Question 7

Give 3 features of starch and explain how this feature enables it to act as a storage substance.

Answer 7

1. Coiled / helical / spiral2. (So) compact / tightly packed / can fit (lots) into a small space3. Insoluble4. (So) no osmotic effect / does not leave cell / does not affect water potential5. Large molecule / long chain6. (So) does not leave cell / contains large number of glucose units7. Branched chains8. (So) easy to remove glucose

Question 8

An arteriole is described as an organ. Explain why.

Answer 8

Made of more than one type of tissue

Question 9

An arteriole contains muscle fibres. Explain how these muscle fibres reduce blood flow to capillaries.

Answer 9

1. (Muscle) contracts2. (Arteriole) narrows/constricts/reduces size of lumen/vessel / vasoconstriction

Question 10

A capillary has a thin wall. This leads to rapid exchange of substances between the blood and tissue fluid. Explain why.

Answer 10

Short diffusion distance/pathway

Question 11

Blood flow in capillaries is slow. Give the advantage of this.

Answer 11

More time for exchange/diffusion (of substances)

Question 12

Kwashiorkor is a disease caused by a lack of protein in the blood. This leads to a swollen abdomen due to a build up of tissue fluid.Explain why a lack of protein in the blood causes a build up of tissue fluid

Answer 12

1. Water potential (in capillary) not as low/is higher/less negative / water potential gradient is reduced2. Less/no water removed (into capillary)3. By osmosis (into capillary)

Question 13

Flatworms are small animals that live in water. They have no specialised gas exchangeor circulatory systems.Name the process by which oxygen reaches the cells inside the body of this flatworm.The body of a flatworm is adapted for efficient gas exchange between the water andthe cells inside the body.-explain how two features of the flatworm’s body allow efficient gasexchange.

Answer 13

Diffusion1. (Thin / flat body) so short distancefor diffusion / short diffusionpathway2. (Thin / flat body so) large surfacearea to volume ratio

Question 14

A leaf is an organ. What is an organ?

Answer 14

A group of tissues

Question 15

Name the monomers that form a cellulose molecule.What sort bond does it have?What is the chemical group at the end?

Answer 15

β/Beta glucoseGlycosidicHydroxyl

Question 16

Show two ways in which the structure of cellulose is different from the structure of starch

Answer 16

Starch1. (1,4 and) 1,6 bonds/contains 1,6 bonds /branching2. All glucoses/monomers same way up3. Helix/coiled/compact4. Alpha glucose5. No (micro/macro) fibrils/fibresCellulose1. 1,4 bonds / no 1,6 bonds / unbranched /straight;2. Alternate glucoses/monomers upside down3. Straight4. Beta glucose5. Micro/macrofibrils/fibres

Question 17

Explain one way in which the structure of cellulose is linked to its function.

Answer 17

1. H-bonds / micro/macro fibrils /fibresor2. Strength / rigidity / inelasticity;

Question 18

Describe how tissue fluid is formed and how it is returned to the circulatory system.

Answer 18

A. Formation1. High blood / hydrostatic pressure /pressure filtration2. Forces water / fluid out3. Large proteins remain in capillaryB.Return4. Low water potential in capillary /blood;5. Due to (plasma) proteins;6. Water enters capillary / blood;7. (By) osmosis;8. Correct reference to lymph

Question 19

Give two ways in which a bacterium could become resistant to an antibiotic.

Answer 19

1. Mutation2. Horizontal transmission /conjugation

Question 20

Describe the function of a chloroplast.

Answer 20

1. Absorbs/traps/uses light2. For photosynthesis3. Produces carbohydrates/sugars/ lipids/protein

Question 21

Chlamydomonas lives in fresh water ponds. Use your knowledge of osmosis to suggest an advantage of using starch as a carbohydrate store.

Answer 21

InsolublethereforeReduces/’stops’ water entry/osmosis / does not affect water potential / is osmotically inactive

Question 22

Do the following contain C H and O only. T or F ?StarchGlycogenDeoxyriboseDNA helicase

Answer 22

TTTF

Question 23

Are the following made of amino acid monomers? T or F?StarchGlycogenDeoxyriboseDNA helicase

Answer 23

FFFT

Question 24

Are the following found in animal and plants cells? T or F?StarchGlycogenDeoxyriboseDNA helicase

Answer 24

FFTT

Question 25

Which atoms that are removed when the two β-glucose molecules are joined by condensation.

Answer 25

Two hydrogens and one of the oxygens from OH groups on carbons 1 and 4

Question 26

Hydrogen bonds are important in cellulose molecules. Explain why.

Answer 26

1. Holds chains/cellulose molecules together/forms cross links between chains/cellulose molecules/forms microfibrils2. Providing strength/rigidity (to cellulose/cell wall)3. Hydrogen bonds strong in large numbers

Question 27

A starch molecule has a spiral shape. Explain why this shape is important to its function in cells (3).

Answer 27

Compact so occupies small space i.e. tightly packed

Question 28

Give two examples of organs

Answer 28

1) The leaf is an example of a plant organ. Its made of the following tissues: lower epidermis, spongy mesophyll, palisade mesophyll, xylem, phloem and upper epidermis.2) The lungs is an example of an animal organ. Its made of the following tissues: squamous epithelium tissue, fibrous connective tissue and blood vessels

Question 29

Which components of blood do not normally enter the tissue fluid?

Answer 29

Plasma proteins - red blood cells or big proteins as they are too big to be pushed through the cappilary walls

Question 30

Define what the systemic circulation does and what the pulmonary circulation does

Answer 30

Systemic = carries blood between the heart and all other parts of the bodyPulmonary = transports blood between the heart and the lungs

Question 31

Explain the differences between arteries, arterioles and veins.

Answer 31

Arteries = carry blood from the heart to the rest of the body. thick muscular wall, Thick elastic wall, relatively small lumen, blood under high pressure and valvesCapillaries = No muscle, No elastic tissue, relativley large lumen, blood under low pressure, no valvesVeins = Thin muscle wall, little elastic tissue, relativley large lumen, blood under low pressure, semilunar valves

Question 32

Identify three organ systems

Answer 32

1) the circulatory system = includes the heart and blood vessels2) the shoot system = includes buds, stems and flowers3) The respiratory system = includes the lungs, the tranchea and the bronchi

Question 33

Give three structures that plant cells have that animal cells don’t have

Answer 33

1) rigid cell wall = made of cellulose, it supports and strengthens the cell2) permanant vacuole = contains cell sap, a weak solution of sugar and salts3) chloroplasts - where photosynthesis occurs, which makes food for the plant. They contain a gren substance called chlorophyll.

Question 34

Describe what chloroplasts are

Answer 34

Chloroplasts are surrounded by a double membrane and are also have membranes inside called thylakoid membranes. These membranes are stacked up in the chloroplast to form grana.Grana are linked together by lamellae - thin, flat pieces of thylakoid membrane.Some parts of photosynthesis happen in the grana and other parts happen in the stroma.

Question 35

Describe examples of 1 animal and 2 plant tissues.

Answer 35

1) squamous epithelium tissue = a single layer of flat cells lining a surface. Squamous epithelium tissue is found in many places including the alveoli in the lungs2) phloem tissue transports sugars around the plant. Its arranged in tubes and is made up of sieve cells, companion cells and some ordinary plant cells. Each sieve cell has end walls with holes in them so that sap can move easily through them. These end walls are called sieve plates.3) Xylem tissue = is a plant tissue with two jobs - it transports water around the plant, and it supports the plant. It contains xylem vessel cells and parenchyma cells

Question 36

Give 3 features of starch and explain how this feature enables it to act as a storage substance.

Answer 36

1. Compact or ‘tightly packed’ as it is helical /spiral/coiled2. Insoluble i.e.prevents osmosis/uptake of water / does not affect water potential / (starch) does not leave cell3. It is a large molecule made froma long chain do does not leave cell

Question 37

The structure of cellulose is related to its role in plant cell walls. Explain how.

Answer 37

1. Long/straight/unbranched chains (of glucose); 2.(Joined by) hydrogen bonds3. Form (micro)fibrils/(macro)fibrils4.which provide rigidity/strength/support

Question 38

The aorta has many elastic fibres in its wall. An arteriole has many muscle fibres in its wall.Explain the importance of elastic fibres in the wall of the aorta.

Answer 38

1.Stretches/’expands’ under high pressure/when ventricle contracts / systole2. Recoils/’springs back’ under low pressure/when ventricle relaxes / diastole3. Smooths blood flow / maintains blood pressure / reduces pressure surges;

Question 39

Explain the importance of muscle fibres in the wall of an arteriole.

Answer 39

1. Muscle) contracts;2. (Arteriole) constricts / narrows/alters size of lumen / reduces/regulates blood flow (to capillaries);

Question 40

Efficient exchange of substances in the capillaries is linked to the rate of blood flow. Explain how.

Answer 40

(More) time for exchange of substances

Question 41

Pernicious anaemia is another type of anaemia. One method of identifying pernicious anaemia is to measure the diameter of the red blood cells in a sample of blood that has been diluted with an isotonic salt solution. Explain why an isotonic salt solution is used to dilute the blood sample.

Answer 41

Has same water potentialNo (net) water movement / osmosisCells will not swell/burst/change size

Question 42

Haemoglobin has a quaternary structure. Explain what is meant by a quaternary structure.

Answer 42

More than one polypeptide chain

Question 43

Name the process in which cells become adapted for different functions.

Answer 43

Differentiation/specialisation

Question 44

Plants that do not have a plentiful water supply have developed a range of other adaptations to limit water loss through transpiration. These plants are called xerophytes.These are plants that are adapted to living in areas where their water losses due to transpiration may exceed their water uptake. Their modifications to reduce water loss include (5) :

Answer 44

• Thick cuticle: The thicker the cuticle, the less water can escape. Many evergreen plants for example holly have thick cuticles to reduce water loss especially during winter.• Rolling up of leaves: Most leaves have their stomata confined to the lower epidermis. The rolling of leaves protects the lower epidermis from the outside and helps trap a region of still air. The region becomes saturated with water vapour so there is no water potential gradient between the inside and outside. Plants such as marram grass roll their leaves.• Hairy leaves: A thick layer of hairs on leaves help trap moist air next to the leaf surface. The water potential gradient between inside and outside is reduced therefore less water is lost through transpiration. One type of heather plant has this.• Stomata in pits or grooves: These also trap moist air and reduce the water potential gradient. Pine trees use this modification.• Reduced surface area to volume ratio of the leaves: By having leaves that are small and roughly circular in cross-section e.g. pin needles, the rate of water loss can be reduced.