6.1.1 cellular control

Question 1

how does the primary structure have a direct impact on the tertiary structure
6.1.1(a)

Answer 1

primary structure of the protein determines which R groups appear in which position and therefore has a direct impact on the bonding in the tertiary structure

Question 2

what is a mutation
6.1.1(a)

Answer 2

change in the DNA base sequence cause by mutagens eg-UV light, radiation and certain chemicals

Question 3

what happens at point substitution
6.1.1(a)

Answer 3

one of the bases in the gene is changed which leads to an incorrect amino acid being added to the polypeptide

Question 4

what happens as a result of the point substitution
6.1.1(a)

Answer 4

as an incorrect amino acid is added to the polypeptide the primary structure will change. This affects the bonding between R groups so this results in a different tertiary structure.

Question 5

how could a change to the tertiary structure be beneficial
6.1.1(a)

Answer 5

it could result in a protein that works better eg-the active site may be more specific to a substrate

Question 6

how could a change to the tertiary structure be deleterious
6.1.1(a)

Answer 6

the protein may lose its function eg-the active site may no longer be specific to the substrate

Question 7

what else could one of the codons be mutated to
6.1.1(a)

Answer 7

stop codon-this leads to a truncated protein which is deleterious and non-functional

Question 8

what is a silent mutation
6.1.1(a)

Answer 8

when the mutated and original codon code for the same amino acid this is possible due to the generate nature of the genetic code.
-normally this occurs at the 3rd base

Question 9

what is insertion mutation
6.1.1(a)

Answer 9

when an additional nucleotide is added somewhere in the base sequence

Question 10

what does insertion mutation cause
6.1.1(a)

Answer 10

due to the non-overlapping nature of the genetic code the insertion causes every codon after the mutation to shift and change. This is cause frame shift

Question 11

what happens if the entire codon is inserted
6.1.1(a)

Answer 11

one amino acid will be added to the final protein but the remainder of the primary sequence will stay the same

Question 12

what is a deletion mutation
6.1.1(a)

Answer 12

where one or more nucleotides is removed from the base sequence.

Question 13

what does the deletion mutation cause
6.1.1(a)

Answer 13

frame shift-every codon downstream of the mutation to change

Question 14

what happens if the entire codon is deleted
6.1.1(a)

Answer 14

one amino acid would be missing from the final protein but the remainder of the primary sequence would stay the same

Question 15

what is an operan
6.1.1(b)

Answer 15

A cluster of genes under the control of a promoter.

Question 30

what is the body plan of the organism
6.1.1(c)

Answer 30

the body plan of an organism is its overall organisation
eg-having the correct number of limbs in the correct places

Question 31

what is the body plan of an organism controlled by and where are they found
6.1.1(c)

Answer 31

the body plan/body development of an organism is controlled by homeobox genes which are found in plants, animals and fungi

Question 32

what is a characteristic of the homeobox genes
6.1.1(c)

Answer 32

there sequences are highly conserved by natural selection as because mutations are lethal

Question 33

what happens if the individuals body plan doesn’t develop correctly
6.1.1(c)

Answer 33

its unlikely that the organism will be able to survive

Question 34

what is the function of the homeobox gene
6.1.1(c)

Answer 34

codes for the transcription factor homeodomain

Question 35

what is the homeodomain
6.1.1(c)

Answer 35

DNA binding site of the transcription factor

Question 36

how long is the homeobox sequence
6.1.1(c)

Answer 36

the sequence in 180 base pairs long.

Question 37

how are homeobox genes expressed
6.1.1(c)

Answer 37

homeobox genes are expressed in a set order during development to ensure the embryo is pattered correctly.

Question 38

what do homeobox genes regulate
6.1.1(c)

Answer 38

they regulate levels of apoptosis and mitosis

Question 39

what are hox genes
6.1.1(c)

Answer 39

homeobox genes found in animals only

Question 40

what do hox genes control
6.1.1(c)

Answer 40

body plan development in animals only. They control which body part grows where

Question 41

what happens if hox genes are mutated
6.1.1(c)

Answer 41

mutations to Hox genes are almost always lethal. The body plan is severely disrupted to the point its non functional

Question 42

what do hox genes encode
6.1.1(c)

Answer 42

hox genes encode homeodomain proteins-DNA binding site of the transcription factor

Question 43

what are the 2 processes that control body plan
6.1.1(d)

Answer 43

mitosis and apoptosis

Question 44

what is mitosis
6.1.1(d)

Answer 44

production of new cells
for growth repair and reproduction

Question 45

what is apoptosis
6.1.1(d)

Answer 45

apoptosis is programmed cell death
to remove old cells

Question 46

when is apoptosis needed
6.1.1(d)

Answer 46

to seperate developing structures eg-fingers,toes

Question 47

what is mitosis and apoptosis controlled by
6.1.1(d)

Answer 47

hox genes

Question 48

what do hox genes respond to

Answer 48

internal and external stimuli