cellular control

Question 1

what is a mutation

Answer 1

any change to base sequence of DNa

Question 2

what are the types of mutations

Answer 2

substitution: one or more bass are swapped for another base

deletion: one or more basses are removed

insertion: one or more bases are added

Question 3

what effect could mutations have

Answer 3

as the order of bases determine the order and type of amino acids, completely different proteins could be made as the primary structure of the protein could change

Question 4

what is frameshift mutation

Answer 4

when an insertion or deletion changes the way the rest of the base sequence is read. the earlier the frameshift mutation the greater the effect it will have on the protein.

Question 5

what is the effect of neutral mutation

Answer 5

the protein function is not affects as the amino acids not change or amino acid is similar chemically or mutated triplet code not involved with protein function

Question 6

what can be the effects of beneficial mutation

Answer 6

increase chance of survival as the organism now has an advantage.
natural selection ensure this mutation is passed onto future generations

Question 7

what can be the effects of harmful mutation

Answer 7

decreases chance of survival as organism now have a disadvantage
can also affect protein production with can lead to genetic disorder

Question 8

why do the function and structure of cells differ

Answer 8

despite carrying the same genes different cells will have different expressed genes

Question 9

what are transcription factors

Answer 9

proteins that bind to DNA and switch genes on or off by increasing or decreasing the rate of transcription

their shape determine whether or not they can bind to DNA

Question 10

what are the two types of transcription factors

Answer 10

activators ( start transcription)
repressors ( stop transcription)

Question 11

where do transcription factors bind to in eukaryotes and prokaryotes

Answer 11

eukaryotes: specific dna does near the start of their target genes
prokaryotes: the factors bind to operons

Question 12

what is an operon

Answer 12

a section of DnA that contains a cluster of structural genes, control elements and sometimes a regulatory gene

Question 13

what are structural genes

Answer 13

genes that code for useful proteins e.g enzymes

Question 14

what are the control elements

Answer 14

a promoter ( DnA sequence located before structural genes that RNA polymerase bind to) and an operon ( DNa sequence that factors bind to)

Question 15

what are regulatory genes

Answer 15

genes that code for activators and repressors

Question 16

what is E.coli

Answer 16

a bacterium that respires glucose but can use lactose in the absence of glucose

Question 17

what is the lac operon

Answer 17

the section of DNA that code for the enzyme needed to respire glucose

Question 18

what are the 3 structural genes found on the lac operon and what is the function of the protein they produce

Answer 18

lacZ lacY lacA

the proteins they produce help bacteria digest lactose

Question 19

lac operon what happens when lactose is not present

Answer 19

1. regulatory gene lacl produce the lac repressors which binds to the operator site
2. transcription is blocked as RnA polymerase cannot bind to the promoter

Question 20

lac operon what happens when lactose is present

Answer 20

1. lactose binds to the lac repressors and changes it shape
2. the repression can no longer bind to the operator site so move off
3. RNa polymerase can now begin transcription of the structural genes

Question 21

what are intro and exons

Answer 21

introns- section of DNA that don’t code for amino acids

exon- the rest of DNA that code for amino acids

Question 22

how is gene expression controlled at post - transcriptional level

Answer 22

primary transcripts ( mRNA strands contain introns and exons) are edited to remove the introns by a process called splicing. the exons are then jokes together to form mature MRNA strands
the mature mRNA then leaves the nucleus to be translated

Question 23

how is gene expression controlled at post- translational level

Answer 23

molecules that control protein activiaton work by binding to cell membranes and triggering the production of cAMP
this activates proteins inside the cell by altering their 3D structure

Question 24

what is a body plan

Answer 24

the general structure of an organism

Question 25

what are Hox genes

Answer 25

genes that code for proteins which control body plan development

Question 26

what are homeobox sequence

Answer 26

regions on hox genes which are highly conserved
(these sequences have changed very little during the evolution of the organisms)

Question 27

how do hox genes control development

Answer 27

homeobox sewage code for a part of the protein called homeodomain which binds to sites on DNA enabling the protein to work as transcription factors. the protein binds to DNA and activates or repress transcription

Question 28

what is apoptosis

Answer 28

a highly controlled process where cells die and breakdown as part of normal development

Question 29

what are the steps of apoptosis

Answer 29

1. enzymes inside the cell break down cell components
2. the cell begins to shrink and break down into fragments
3. phagocytes engulf and digest the cell fragments

Question 30

what role do mitosis and apoptosis play in development

Answer 30

mitosis and differentiation create the bulk of body parts and apoptosis refined the body parts by removing unwanted structures

genes that control mitosis are switches in and off in appropriate cells so correct body plan develop