Biology paper one exam questions frequent

Question 1

give two advantages of using an electron microscope instead of a light microscope (2 marks)

Answer 1

higher resolution
higher magnification

Question 2

describe the process of the cell cycle (4 marks)

Answer 2

DNA/ chromosomes replicate/duplicate
mitochondria/ribosomes/ sub cellular structures increase in number/replicate
one set of chromosomes is pulled/moved to each end of the cell
the cytoplasm and cell membrane divides to form two identical cells

Question 3

what is a stem cell? ( 2 marks)

Answer 3

an undifferentiated cell that differentiate into any kind of cell

Question 4

what properties must exchange surfaces have?

Answer 4

large surface area
thin cell wall (one cell thick)
steep concentration gradient/ large concentration gradient
good ventillation

Question 5

how is the small intestine adapted for efficient absorption

Answer 5

villi and micro-villi increase surface area
good blood supply to maintain steep concentration gradient
walls one cell thick, thin membrane for short diffusion path
many mitochondria for active transport
small intestine is long which gives more time for diffusion

Question 6

how are the lungs adapted for efficient gas exchange (4 marks)

Answer 6

alveoli- lots so increases surface area
thin membrane- one cell thick wall for short diffusion path
good ventilation for gas exchange to maintain a steep concentration gradient
good blood supply to maintain sleep concentration gradient

Question 7

a cell is put into pure water- explain what happens to it (3)

Answer 7

water moves into the cell via osmosis
from a high water concentration to low concentration
it increases in mass

Question 8

Why do you bloat the potatoes (in the RP) (1 mark)

Answer 8

to remove excess water, which could effect the final mass, as you are trying to measure water inside potato not outside

Question 9

What is an enzyme (2 marks)

Answer 9

a biological catalyst made from protein
catalyses reactiojn

Question 10

What is the role of bile (3 marks)

Answer 10

emulsifies fats/ lipids
neutralizes stomach acid
breaks down fats to give a large surface area
large surface area for enzyme to work on

Question 11

In the RP practical- how could you find a more optimum PH?

Answer 11

repeat at smaller intervals

Question 12

define the term double circulatory system

Answer 12

right side of heart pumps blood to lungs
left side of heart pumps blood to body

Question 13

compare the structure of artery and a vein(3 marks)

Answer 13

arteries have more muscle
arteries have more elastic
arteries have smaller lumen

Question 14

how does a coronary heart disease cause a heart attack?

Answer 14

fat builds up and blocks heart so blood cannot circulate efficiently and oxygen cannot get to heart
less aerobic respiration
less energy released
heart muscles contract

Question 15

How does a stent prevent a heart attack?

Answer 15

metal mesh holds artery open
so blood can throw through and oxygen can get to heart muscle

Question 15

How does a stent prevent a heart attack?

Answer 15

metal mesh holds artery open
so blood can throw through and oxygen can get to heart muscle

Question 16

what is transpiration? (3 marks)

Answer 16

evaporation of water from leaves to stomata
causes more water to move up xylem
more water absorbed into roots via osmosis

Question 17

what is a pathogen?

Answer 17

micro-organisms that cause disease

Question 18

why can’t anti-biotics be used to treat viruses?

Answer 18

viruses get inside cells
anti-biotics cant get into cells

Question 19

how do white blood cells protect you from getting ill? (3 marks)

Answer 19

engulf pathogen
make anti- toxins
make antibodies

Question 20

a plant has a disease where parts of its leaves turning black. Explain why this plant grows slowly

Answer 20

less chloroplasts/chlorophyll
less light absorbed/ less photosynthesis
less glucose produced
less proteins/cellulose/less energy released for growth

Question 21

Explain how a vaccination for HIV (or any disease) prevents a person from developing HIV infection

Answer 21

• inactive HIV / virus is injected (into bloodstream / muscle / body)
• white bloods cells produce antibodies (against inactive virus)
• (if infected with HIV) correct / specific antibodies are produced quickly
• antibodies destroy/kill the (active) virus / HIV

Question 22

describe how monoclonal antibodies are produced (4)

Answer 22

• HIV / antigen / protein injected into mouse extract
• collect (mouse) lymphocytes that make a specific antibody to HIV / antigen / protein
• lymphocytes are combined with a tumour cell to create a hybridoma (hybridoma)
• Hybridoma is cloned to create many cells that produce the antibody

Question 23

Why is the aseptic technique of working near a bunsen burner used?

Answer 23

upward current of air moves pathogens away

Question 24

Why is the aseptic technique of flaming the instruments used?

Answer 24

kill pathogens on the instruments/ prevent contamination

Question 25

why is the aseptic technique of not taking the lid completely off the agar plate used?

Answer 25

prevents contamination of any pathogens in the air

Question 26

explain how your heart rate increasing while excersizing is beneficial (5)

Answer 26

Muscles supplied with blood faster
Muscles get more oxygen
More aerobic respiration
More energy realised for muscle contraction
Carbon dioxide removed faster

Question 27

explain how breathing rate/ breathing volume increasing while excersizing is beneficial

Answer 27

Muscles get more oxygen
More aerobic respiration
More energy realised for muscle contraction
More carbon dioxide removed

Question 28

In a practical why are multiple repeats carried out?

Answer 28

to calculate an accurate mean