Topic 6

Question 1

What is DNA

Answer 1

Chemical that all genetic material in a cell is made up from. Contains genetic info

Question 2

What is the structure of DNA

Answer 2

Polymer made up of repeating units called nucleotides. Each nucleotide consists of one sugar and one phosphate molocule and one base. two coiled strands in double helix strand

Question 3

What is a gene

Answer 3

Small section of DNA found on chromosome l. Each gene codes for a particular sequence of amino acids

Question 4

What is a genome

Answer 4

Entire set of genetic materials

Question 5

What DNA bases join up

Answer 5

A T

And C G

Question 6

What are mutations

Answer 6

A random change in an organisms DNA

Question 7

What do mutations so abs how do the chance of them happening increase

Answer 7

Chance of mutation increases by exposure to radiation. It changes sequences of DNA bases in a gene.

Question 8

What is insertions

Answer 8

When a new base is inserted into the DNA base sequences. It has a knock on effect on all the others

Question 9

What are deletions

Answer 9

When a random base is deleted from the DNA Base sequences

Question 10

What are substitutions

Answer 10

When a random base in the dna is changed to w difference base

Question 11

What is sexual reproduction

Answer 11

Involves fusion of male and female gametes the offspring contain a mixture of parents genes

Question 12

What is asexual production

Answer 12

There’s only one parent so offspring genetically identical to one parents

Question 13

Where does mitosis occur in and what is product

Answer 13

Asexual reproduction, offspring of identical to one parent

Question 14

What is meosis

Answer 14

Producing cells which have half the normal number of chromosome s

Question 15

What are the steps of meiosis

Answer 15

• dulpicates genetic information, chromosomes arrange in pairs.
• pairs line up in middle, they are then pulled apart.
  Divides once again and chromosomes are pulled apart

Question 16

What does meiosis result in

Answer 16

4 gametes, they’re all genetically different than a

Question 17

Why is sexual production better than asexual

Answer 17

• offspring have mixture of two sets of chromosome
• variation increases can survive change in environment
• can use selective breeding

Question 18

Why is asexual production better than sexual

Answer 18

• only needs one parent
• less energy used to find a mate
• faster
  Many identical offspring in favourable condition

Question 19

Give an example of a organism that can reproduce both asexual and sexually

Answer 19

Malaria cause by parasite, mosquito bites a human the parasite produced sexually in mosquito and asexually in human

Question 20

What are the male and female chromosonee

Answer 20

Males - XY

female XX

Question 21

What is a allele

Answer 21

Different versions of a gene

Question 22

What is a organism called that has two of the same alleles

Answer 22

Homozygous

Question 23

What is a organism called that has different alleles

Answer 23

Heterozygous

Question 24

What is the capital letter allele called

Answer 24

Dominant

Question 25

What is the lower case allele called

Answer 25

Recessive

Question 26

What is the genotype

Answer 26

Combination is alleles you have

Question 27

What is phenotype

Answer 27

The charecteristucs

Question 28

What is cystic fibrosis caused by and what is it

Answer 28

A genetic disorder of ceell membranes producing a lot of thick sticky mucus. Caused by RECESSIVE allele. For a child to have the disorder both parents must be carried

Question 29

What is polydactyl

Answer 29

Genetic disorder where a baby is born with extra fingers and toes . Caused by DOMINANT allele

Question 30

What are pros and cons of screening for genetic disorders

Answer 30

Cons :
- implies that people with genetic problems are undesirable 
- may come a point where everyone wants to screen their embryos so they can pick characteristics 
- expensive
FOR: 
- help stop people suffering 
- treating disorders 
- laws to stop it going too far

Question 31

WhAt conclusions did Mendel reach from his experiment with pea plants

Answer 31

• charecteristsic in plants are determined by hereditary units
• hereditary units are passed on to offspring
• can be dominant and recessuve

Question 32

What can introduce variation

Answer 32

Mutations

Environmental changes

Question 33

What is the theory of evolution

Answer 33

All today’s species have evolved from simple life forms

Question 34

What was Charles Darwin’s theory on evolution

Answer 34

Survival of the fittest. The successful organisms are more likely to reproduce and pass on characteristics

Question 35

What is speciation

Answer 35

Over a long period of time the phenotype of organisms change that a new species of formed.
This cos. Also happen when species change so much it can’t interbreed

Question 36

Why is extinction caused

Answer 36

• environmental changes too wuick
• new predator
• new diseases
• catastrophic event

Question 37

Why didn’t everyone agree with Darwin

Answer 37

Went against religious views
He couldn’t explain why these new characteristics appeared
- wasn’t any evidence

Question 38

What was Lamarck ideas

Answer 38

Changed in a organism aquires during its life time will be passed on. E.g. if a rabbit used its leg a lot then the legs would get longer and offspring would be same for

Question 39

What is selective breeding

Answer 39

When humans artificially select plant or animals that are going to breed so that genes for particular characteristics remain in population

Question 40

Why would selective breeding be used

Answer 40

• animals to produce more meat and milk

- crops to be disease resistance

Question 41

What is the main problem with selective brooding

Answer 41

Reduces gene pool

Invreeding can cause health problems

Question 42

What is a genetic engineering

Answer 42

Transfers gene responsible for desirable characteristics from one organisms genome into another organism