GCSE Cells & Biochemistry Knowledge

Question 1

what are the functions of white blood cells?

Answer 1

1. ingest pathogens
2. produce antibodies
3. produce antitoxins

Question 2

what does producing specific antibodies to kill a particular pathogen lead to?

Answer 2

immunity from that pathogen

Question 3

what happens if a large proportion of the population is immune to a pathogen?

Answer 3

the spread of the pathogen is very much reduced

Question 4

what are the effects of exercise on the body?

Answer 4

1. increase rate of breathing
2. increase depth of breathing
3. increase heart rate

Question 5

what is the organisation of cells, tissues, organs etc. in the stomach?

Answer 5

muscle cells –> muscle tissue (contract to churn bits of food)
glands –> glandular tissue (secrete acid, enzymes & hormones)
epithelial cells –> epithelial tissue (line the stomach to protect it from HCl acid)

Question 6

what can be transferred by evaporation?

Answer 6

heat

Question 7

what is the specific heat capacity of water?

Answer 7

high

Question 8

describe the interaction between oil & water?

Answer 8

oil does not dissolve in water
it can form emulsions with water if an emulsifier is present

Question 9

are vegetable oils saturated or unsaturated?
how can they be hardened?

Answer 9

unsaturated bc they contain a double bond
these may be hardened by hydrogenation to add to the double bond

Question 10

what are the roles of protein in the body?

Answer 10

enzymes
structural components e.g. muscle
antibodies
hormones

Question 11

what is chromatography used for?

Answer 11

to separate mixtures of soluble dyes
& to identify molecules within a mixture

Question 12

what are needed in small amounts for the body to function healthily?

Answer 12

mineral ions & vitamins

Question 13

how are ions lost from the body?

Answer 13

1. via the skin in sweat
2. excess ions are lost via the kidneys in urine

Question 14

what ions make a solution acidic?

Answer 14

H+

Question 15

what is energy from respiration used for?

Answer 15

movement
protein synthesis
synthesis of amino acids in plants
maintenance of constant body temperature

Question 16

what does DNA contain the genetic information for?

Answer 16

features & characteristics

Question 17

what do mutations cause?

Answer 17

new forms of genes

Question 18

what does Darwin’s theory of evolution by natural selection state?

Answer 18

all species of living things have evolved from simple life forms that first developed more than 3 billion years ago

Question 19

why do individual organisms within a species show variation?

Answer 19

differences in the genes they inherit,
the conditions in which they develop
or both

Question 20

where there are new forms of genes (caused by mutations), what can happen if the environment changes?

Answer 20

rapid change in a species

Question 21

what does studying the similarities & differences between organisms allow?

Answer 21

classification of organisms to understand evolutionary & ecological relationships

Question 22

what is a species?

Answer 22

a group of organisms that can interbreed to produce fertile offspring

Question 23

how does fossil evidence show how species have changed over time?

Answer 23

fossils are: evidence of early life forms
the best evidence of organisms that are now extinct
the remains of organisms from millions of years ago found in rocks

Question 24

how are fossils formed?

Answer 24

1. animal traces e.g. footprints, burrows, rootlets
2. animal decayed so left space that was filled by minerals
3. parts of organism had not decayed because a condition for decay was not present (e.g. anaerobic, low temp, low pH, low moisture)

Question 25

what cause new species to arise?

Answer 25

1. isolation - 2 populations of the same species are separated
2. genetic variation - each population has a range of alleles that control their characteristics
3. natural selection - alleles that control the most beneficial characteristics (that help the organism to survive) are selected
4. speciation - populations become so different that they can no longer interbreed successfully to produce fertile offspring