cellular control

Question 1

what is a mutation

Answer 1

random changes in the genetic material (DNA) of a cell that leads to the introduction of variation

Question 2

what is the function of the Lac Operon

Answer 2

an example of a regulatory mechanism at the transcriptional level (i.e. a regulatory mechanism that occurs during transcription)

Question 3

what is a gene mutation

Answer 3

a random change to the base sequence of DNA

Question 4

where can mutations happen

Answer 4

• somatic cells
• gametes

Question 5

gametes (mutation in gametes)

Answer 5

• present in egg or sperm
• can be inherited
• causes cancer family syndrome

Question 6

somatic cells (mutation in somatic cells)

Answer 6

• non - gamete tissue
• cannot be inherited

Question 7

what are the 2 types of mutation

Answer 7

• point mutations/substitutions
• insertion/deletions (or indel mutations)

Question 8

what is a point mutation/substitution

Answer 8

one base pair replaces another. Otherwise known as a substitution.

Question 9

what is insertion/deletion (or indel mutations)

Answer 9

one or more nucleotides are inserted, or deleted from a length of DNA, this may cause a frame shift.

Question 10

what is the difference between the coding and template strands in DNA

Answer 10

• nucleotides, add on to a template strand.
• mRNA, is the same as the coding strand.

Question 11

what is translation

Answer 11

mRNA, is used, to put the amino acids in the correct order during protein synthesis.

Question 12

what is silent mutation

Answer 12

a mutation where the same amino acid is coded for using a different triplet thus meaning there are no consequences.

Question 13

what is a missense mutation

Answer 13

one base change, leads to a different amino acid being made. The impact this had, depends on the amino aid that is being made.

Question 14

what is nonsense mutation

Answer 14

one point mutation which leads to a stop codon. Therefore, stopping the production of the polypeptide.

Question 15

what is a frameshift mutation

Answer 15

• a deletion

Question 16

what are 3 categories of mutations

Answer 16

• beneficial
• neutral
• harmful

Question 17

what is a beneficial mutation

Answer 17

different alleles, e.g. paler skin enables vitamin D to be made whilst black skin has more melatonin thus protecting from skin cancer.

Question 18

what is a neutral mutation

Answer 18

• inability to smell certain flowers
• different shaped ear lobes

Question 19

what is a harmful mutation

Answer 19

• Duchenne muscular dystrophy (nonsense mutation)

Question 20

what is an activator

Answer 20

starts transcription

Question 21

what is a repressor

Answer 21

stops/prevents transcription

Question 22

what does the regulatory gene do (repressor)

Answer 22

stops transcription

Question 23

what is the function of B galactosidase

Answer 23

hydrolyses lactose -> glucose and galactose

Question 24

what is the function of lactose permease

Answer 24

allows lactose to enter the bacterial cell

Question 25

why is gene expression so important in eukaryotes

Answer 25

controlling gene expression, is important to ensure the correct proteins are being made by the correct cells.

Question 26

what do transcription factors control

Answer 26

they control which genes, are switched on or off

Question 27

what do transcription factors bind to

Answer 27

specific promotor region

Question 28

what is post transcriptional gene regulation

Answer 28

splicing out non-coding intron regions of transcribed mRNA

Question 29

what is alternative splicing

Answer 29

genes can be spliced in different ways. Therefore length of DNA can encode more than one protein, depending on how it is spliced

Question 30

what is post translational gene regulation

Answer 30

• modifications, to the proteins or amino acids
• e.g. adding non protein groups, like lipids or phosphates, forming extra bonds, folding or shortening, modification of cAMP.

Question 31

what is a homeotic gene

Answer 31

a large group of genes, that control anatomical development

Question 32

what is a homeobox sequence

Answer 32

part of the gene. that codes the homeodomain

Question 33

what is the homeodomain sequence

Answer 33

part of a protein, that is shaped in a way, that allows it to bind to DNA and act as a transcription factor.

Question 34

where are homeobox genes found

Answer 34

in plants, animals and fungi.

Question 35

what does the term ‘collinearity’ mean

Answer 35

hox genes, are activated during development of the embryo. They are expressed, in order, from front to back

Question 36

how are the hox genes regulated

Answer 36

• maternally supplied mRNA, in egg cytoplasm -