Biology

Question 1

Cytoplasm

Answer 1

A jelly-like material that contains dissolved nutrients and salts and structures called organelles. It is where many of the chemical reactions happen.

Question 2

Chloroplast

Answer 2

Organelle that contains the green pigment, chlorophyll, which absorbs light energy for photosynthesis. Contains the enzymes needed for photosynthesis.

Question 3

Permanent vacuole

Answer 3

Filled with cell sap to help keep the cell swollen.

Question 4

Mitochondria

Answer 4

Organelles that contains the enzymes for respiration, and where most energy is released in respiration.

Question 5

Ribosomes

Answer 5

Tiny structures where protein synthesis occurs

Question 6

Bacteria

Answer 6

Bacteria are all single-celled. The cells are all prokaryotic. This means they do not have a nucleus or any other structures which are surrounded by membranes. Larger bacterial cells may be visible using a light microscope, however an electron microscope would be needed to see the details of the cell organelles.

Question 7

Specialised cell-sperm

Answer 7

The head contains genetic information and an enzyme to help penetrate the egg cell membrane. The middle section is packed with mitochondria for energy. The tail moves the sperm to the egg. Red blood cells. Contain haemoglobin to carry oxygen to the cells.

Question 8

Specialised cell- root hair

Answer 8

Plants absorb water from the soil by osmosis. Root hair cells are adapted for this by having a large surface area to speed up osmosis.

Question 9

Which is the correct calculation for magnification of a light microscope?

Answer 9

Magnification of eyepiece x magnification of objective

Question 10

What term describes the part of a bacterial cell which provides movement?

Answer 10

Flagella

Question 11

What name is given to cells in the trachea?

Answer 11

Ciliated cells are found within the trachea. They move to propel mucus from your airway.

Question 12

What affect does extremely high pH have on enzymes?

Answer 12

Extremely high pH denatures enzymes

Question 13

What does the term optimum mean for enzyme temperature?

Answer 13

Optimum is the temperature which gives the highest enzyme activity.

Question 14

What type of enzymes break down carbohydrates?

Answer 14

Carbohydrates are broken down by carbohydrase enzymes

Question 15

What type of enzymes break down fats?

Answer 15

ipase enzymes

Question 16

What type of enzymes break down proteins?

Answer 16

Proteins are broken down by protease enzymes

Question 17

What type of enzyme is amylase?

Answer 17

mylase is a carbohydrase found in saliva in your mouth.

Question 18

What is the test for reducing sugars?

Answer 18

Benedict’s solution.

Question 19

What does a calorimeter measure

Answer 19

Calorimeters measure the energy stored within a food.

Question 20

What is the correct calculation for the rate of an enzyme reaction

Answer 20

The correct calculation for rate of reaction is amount of substrate used / time taken.

Question 21

What part of a cell controls what enters and exits?

Answer 21

A

Cell membrane

Question 22

What process involves the movement of water across a membrane?

Answer 22

Diffusion

Question 23

Describe the structure of a generalised animal cell

Answer 23

the cytoplasm is made from water and is where cellular reactions occur
the nucleus contains genetic material which controls the cell
the membrane controls the movement of molecules into and from the cell
mitochondria are the site of respiration
ribosomes are the site of protein synthesis

Question 24

Describe the structure of a generalised plant cell

Answer 24

the cytoplasm is made from water and is where cellular reactions occur
the nucleus contains genetic material which controls the cell
the membrane controls the movement of molecules into and from the cell
mitochondria are the site of respiration
ribosomes are the site of protein synthesis
the cell wall is made from cellulose and provides support
photosynthesis occurs in chloroplasts
cell sap is stored in the permanent vacuole

Question 25

What conditions can denature an enzyme?

Answer 25

high temperatures | extreme (very high or low) pH

Question 26

Describe the structure of a prokaryotic cel

Answer 26

all bacteria possess prokaryotic cells they do not have a nucleus instead their DNA is present in the cytoplasm the cytoplasm is made from water and is where cellular reactions occur the membrane controls the movement of molecules into and from the cell flagella rotate or move like whips to move bacterial cells a cell wall provides protection

Question 27

Describe the differences between light and electron microscopes.

Answer 27

light microscopes are lower magnification they are also lower resolution light microscopes can study living cells but electron microscopes cannot electron microscopes are more expensive transmission electron microscopes look at cross sections of samples scanning electron microscopes look at samples in three dimensions

Question 28

Describe where enzymes of the digestive system are produced

Answer 28

carbohydrase enzymes are produced in the mouth, pancreas and small intestine lipase enzymes are produced in the pancreas and small intestine protease enzymes are produced in the stomach, pancreas and small intestine

Question 29

What is the total magnification of a light microscope with an eyepiece lens of ×10 and an objective lens of ×40?

Answer 29

10 × 40 = ×400 Total magnification of microscope = magnification of eyepiece lens × magnification of objective lens

Question 30

How many orders of magnitude exist between an ant which is 3 mm long and a human hair which has a diameter of 100 μm? [3 mark]

Answer 30

Ant = 3 mm which is 0.003 m or 10−3 m Human hair = 100 μm which is 0.0001 or 10−4 m So there is one order of difference.

Question 31

If a drawing of a cell in a textbook is 1 cm and the scale shows it to be 0.1 mm in real life, what is its magnification? [2 mark]

Answer 31

1 cm = 10 mm So, 10 mm ÷ 0.1 mm = ×100

Question 32

Compare and contrast diffusion and active transport

Answer 32

diffusion is the net movement of molecules from an area of high to lower concentration active transport is the net movement of molecules from an area of low to higher concentration diffusion is a passive process and does not require energy active transport is an active process and so does require energy diffusion occurs down a concentration gradient active transport occurs up a concentration gradient one mark for suitable example of diffusion, eg oxygen diffuses from the alveoli into the blood in the lungs one mark for suitable example of active transport, eg plants use active transport to absorb nitrates from the soil

Question 33

Describe how both the enzymes of the digestive system and its adaptations help break down foods. [5 marks]

Answer 33

carbohydrase enzymes break down carbohydrates into sugars they are produced in the mouth, pancreas and small intestine lipase enzymes break down fats and oils into fatty acids and glycerol they are produced in the pancreas and small intestine protease enzymes break down proteins into amino acids they are produced in the stomach, pancreas and small intestine the small intestine is about 4 metres long [1 mark] and has millions of tiny projections [1 mark] called villi [1 mark] which increase the surface area [1 mark] to increase diffusion [1 mark]

Question 34

What is a section of DNA that codes for a protein called?

Answer 34

AGene

Question 35

Describe the difference between genotypes and phenotypes? Give an example of each in your answer. [4 marks]

Answer 35

genotypes are letters used to determine characteristics BB, Bb, bb for eye colour (accept other suitable examples) phenotypes are physical descriptions using words that describe genotypes so BB and Bb are brown eyes and bb is blue eyes (accept other suitable examples)

Question 36

State what gamma rays, X-rays and ultraviolet rays are? [1 mark]

Answer 36

Types of ionising radiation