Module 6 - Cellular Control

Question 1

what is a mutation?

Answer 1

a random unpredictable change in DNA

Question 2

what can a mutation affect?

Answer 2

-small part of DNA molecule (gene mutation)
-large pieces of chromosomes/number of chromosomes present (chromosome mutation)

Question 3

what is a gene mutation?

Answer 3

change in the base sequence of a DNA molecule

Question 4

what are the three types of point mutation?

Answer 4

substitutions, insertions, deletions

Question 5

what are the likely effects of a simple substitution?

Answer 5

-no effect due to the degenerate nature of the code
-introduction of a stop codon

Question 6

what is deletion?

Answer 6

section of chromosome breaks off and gets lost within the cell

Question 7

what is translocation?

Answer 7

a section of one chromosome breaks off and joins another non-homologous chromosome

Question 8

what are the causes of mutation?

Question 9

what increases the rate of mutation?

Answer 9

mutagens

Question 10

what are the four stages where gene expression can be controlled or regulated?

Answer 10

Transcriptional control, Post-transcriptional control, Translation control, Post-translational control

Question 11

what is chromatin?

Answer 11

a mixture of DNA and proteins that form the chromosomes found in eukaryotic cells

Question 12

what two enzymes does E.Coli code for?

Answer 12

-lactose permease (which cell to take up lactose)
-lactase (enables cell to hydrolyse lactose to glucose and galactose)

Question 13

what is a chromosomal mutation?

Answer 13

mutation that affects the whole chromosome or a number of chromosomes in a cell

Question 14

what is a frameshift?

Answer 14

caused by insertions and deletions, every codon after the mutation is affected giving the protein a different sequence of amino acids and different tertiary structure

Question 16

what is the exon?

Answer 16

the expressed region within the gene

Question 17

what is the intron?

Answer 17

the intragenic region (region within the gene)

Question 18

how are the introns removed from a gene?

Answer 18

they are spliced

Question 19

what is pre-transcriptional control?

Answer 19

-it produces pre-mRNA which is processed to form mature mRNA
-cap and tail are added to mature mRNA by spliceosomes removing introns

Question 20

what happens in RNA editing?

Answer 20

-it can undergo deletion, addition or substitution which allows a single length of DNA to produce a range of different strands of mRNA

Question 21

how does degradation of mRNA affect the rate of protein synthesis?

Answer 21

the more resistant the molecule the longer it will last in the cytoplasm therefore increasing the rate of protein synthesis

Question 22

how does the binding of inhibitory proteins to mRNA affect the rate of protein synthesis?

Answer 22

it prevents mRNA from binding to ribosomes and the synthesis of proteins

Question 23

what does the activation of initiation factors do in regards to the rate of protein synthesis?

Answer 23

aid binding of mRNA to ribosomes

Question 24

what structural detail of a polypeptide is altered by gene mutations?

Answer 24

the amino acid sequence

Question 25

what is substitution?

Answer 25

one or more bases are swapped for others

Question 26

what are the three types of substitution mutation?

Answer 26

silent, nonsense, mis-sense

Question 27

what is a missense substitution mutation?

Question 33

what is morphogenesis?

Answer 33

the regulation of the pattern of anatomical development

Question 34

what is morphogenesis controlled by?

Answer 34

homeobox genes

Question 35

what are homeobox genes?

Answer 35

-has a sequence of 180 base pairs
-codes for homeodomains (protein segments which act as transcription factors)
-they are ancient and highly conserved
-they switch genes on and off

Question 36

what genes control the development of the body plan?

Answer 36

homeobox genes

Question 37

what does the fact that homeobox have high levels of conservation suggest?

Answer 37

that their activity is fundamental to the development of a working body so any mutation would be fatal

Question 38

what are hox genes?

Answer 38

one specific group of homeobox genes (only in animals)

Question 39

what are the 3 types of symmetry?

Answer 39

radial, bilateral, asymmetry

Question 40

what is radial symmetry?

Answer 40

organisms with a top and a bottom but no left or right side

Question 41

what is bilateral symmetry?

Answer 41

organisms have a left right and a head and tail end

Question 42

what is asymmetry?

Answer 42

organisms have no lines of symmetry

Question 43

what type of genes are homeobox genes?

Answer 43

regalotory

Question 44

what is apoptosis?

Answer 44

programmed cell death

Question 45

what is apoptosis triggered by?

Answer 45

transcription factors made by hox genes