Dna revision

Question 1

what are chromosomes?

Answer 1

they’re long thread like structures that are found in the nucleus, and allow DNA to be accurately copied during these cell divisions.

Question 2

how many chromosomes do we have?

Answer 2

46, 23 pairs.

Question 3

what are the two different types of chromosomes?

Answer 3

Autosomes and sex cells.

Question 4

how many of both do we have?

Answer 4

we have 44 autosomes and 2 sex cells.

Question 5

what is a gene?

Answer 5

a section on dna thats responsible for our traits, eg. hair, eye colour etc.

Question 6

what does dna stand for?

Answer 6

deoxyribonucleic acid.

Question 7

what is dna?

Answer 7

a molecule that contains the genetic code that is unique to every individual

Question 8

what are the four bases in dna?

Answer 8

Adenine, Thymine, Cytosine and Guanine

Question 9

dna is universal, true or false?

Answer 9

true.

Question 10

why might you want to put dna from one organism into another?

Answer 10

to give another organism the genes of the first organism, and since genes are universal, this is possible.

Question 11

what is dna in the shape of?

Answer 11

a corkscrew. and theres usually two strands of dna bound together called a double helix.

Question 12

what happens when dna strands are split?

Answer 12

half of the dna is new and half of it is copied.

Question 13

whats a karyotype

Answer 13

a complete listing/layout of the chromosomes.

Question 14

what are mutations?

Answer 14

changes in the dna sequence.

Question 15

whats a mutagen?

Answer 15

a substance or chemical that increases the number of mutations.

Question 16

what are the two different types of mutations?

Answer 16

point mutations and chromosomal mutations.

Question 17

what causes a point mutation?

Answer 17

when a single base pair is changed, added or deleted.

Question 18

what happens when a base is changed?

Answer 18

it may change the function of a protein, or it may result in the identical protein.

Question 19

what causes a chromosomal mutation?

Answer 19

when larger stretches of dna or complete chromosomes are lost or gained, (which is often fatal).

Question 20

what does a neutral (silent) mutation mean?

Answer 20

it means theres no change in the amino acid, so the final protein remains the same.

Question 21

what does a negative mutation mean?

Answer 21

the new protein doesnt function as well.

Question 22

what does a positive mutation mean?

Answer 22

the new protein functions better, (but this is rare).