Cell control

Question 1

what is apoptosis

Answer 1

programmed cell death

Question 2

how is apoptosis controlled

Answer 2

intrinsic and extrinstic inducers, depends on balance between positive and negative signals

Question 3

intrinsic inducer

Answer 3

intracellular signals- hormones que stim mitosis, DNA damage distrupting cell cycle

Question 4

extrinsic inducer

Answer 4

extracellular signals- nutrient stress in a cell, viral infection

Question 5

role of apoptosis in morphogenesis

Answer 5

as mitosis and cell diff create bulk of body parts
apop refines parts by removing unwanted sturctures
e.g. spacing the nerve cells in CNS

Question 6

where does apoptosis occur

Answer 6

multicellular organisms

Question 7

describe the process of apoptosis

Answer 7

cell shrinkage
DNA and protein degraded
c.m. blebs, chromatin condensation, discontinuous nuc env, cell breaks apart into apoptotic bodies which are phagocytosed along w/blebs by mac

Question 8

why do cells commit suicide

Answer 8

part of body’s defence against pathogens/ dangerous, damaged cells
part of the normal developmental process for the organism

Question 9

what process has a similar biochemical pathway to apoptosis

Answer 9

cell division

Question 10

similarities between apoptosis and mitosis

Answer 10

similar biochemical pathways
tightly controlled
both tiggered by internal and external factors

Question 11

what is morphogenesis

Answer 11

shaping of the organism and its parts

Question 12

when does morphogenesis and cell differentiation occur in animals, plants and fungi

Answer 12

animals- mainly during embryonic stage

plants and fungi- continually

Question 13

what are homebox genes

Answer 13

DNA seqs que contain a homebox seq and inv in reg of patterns of dev and cell diff in animals, plants and fungi

Question 14

how are homebox genes expressed

Answer 14

in specific patterns at particular stages of the organism’s dev

Question 15

what do regulatory/ homeotic genes contain

Answer 15

a homebox seq (180 base pairs) that code for a homeodomain

Question 16

what do regulatory/ homeotic genes contain

Answer 16

a homebox seq (180 base pairs which code for 60 a.a) that code for a homeodomain

Question 17

how many other genes can 1 homeobox gene switch on

Answer 17

many other genes

Question 18

state a characteristic of homeobox genes

Answer 18

highly conserved

Question 19

state a characteristic of homeobox genes

Answer 19

highly conserved in evolution

Question 20

what is the name for the type of homebox gene that animals have

Answer 20

hox genes

Question 21

what are the role of hox genes

Answer 21

control body plan development in animals- correct positioning of body parts

Question 22

what is plants and animals morphology usually governed by

Answer 22

environmental factors

Question 23

in what way are homebox genes conserevd in evolution

Answer 23

the homebox DNA seq evolved at early stage in history of life can be seen in distantly related eukaryotes

Question 24

how many hox box gene clusters are in humans (vertabrates)

Answer 24

4, on different chromosomes

Question 25

why are homebox genes said to be highly conserved

Answer 25

little variation in the DNA sequence

Question 26

what do hox genes code for

Answer 26

proteins that act as transcription factors

Question 27

what does the presence of transcription factors mean

Answer 27

genes can be repressed or activated

Question 28

the order of hox genes along the chromosome corresponds to...

Answer 28

the order the hox genes are expressed

Question 29

what might be the result of an increased number of hox genes

Answer 29

greater complexity in body structure

Question 30

how did hox genes arise

Answer 30

gene duplication

Question 31

what may have been a critical event in the formation of body plans

Answer 31

genetic variation

Question 32

what about hox genes varies between diff types of animals

Answer 32

number and arrangement

Question 33

function of homebox genes

Answer 33

contolling the development of the organism's body and ensure structures develop n the correct positions

Question 34

structure of homebox gene

Answer 34

180 base pairs long

Question 35

what do homebox genes encode

Answer 35

polypeptide sequences that are 60 amino acids long- homeodomains

Question 36

homedomain

Answer 36

transcriptional factors that bind to DNA and switch genes on or off

Question 37

examples of dev rols played by homebox genes

Answer 37

deterination of tail and head of an org and reg balance bw apop and mtiosis

Question 38

how do homeobox genes differ bw species

Answer 38

different numbers of homebox genes

Question 39

suggest why vertabrates have more homeobox genes than invert

Answer 39

.

Question 40

explain how hox genes can cause diff of cells

Answer 40

.

Question 41

point mutation

Answer 41

change in a single nucleotide

Question 42

substitution

Answer 42

1 or more nucleotides replaced

Question 43

insersion

Answer 43

addtion os bases

Question 44

deletion

Answer 44

removal of bases

Question 45

possible effects of substitution on protein sturcture and function

Answer 45

change in primary sturcutre | neutral due to degenerate nature of genetic code

Question 46

poss eff of ins/del on stuc and finc of proteins

Answer 46

frameshift, moving reading frame of seq incorr bases read changes every codn after point of mutation

Question 47

when does del/ins not res in frame shift, eff on protein

Answer 47

if multiples of 3 as correspond w/ | protin formed still aff as new aa added

Question 48

eff of diff mutaions

Answer 48

neutral- no eff on p.type benficial- useful chara harmful- intefre w/ essential processes

Question 49

when do mutations often occur

Answer 49

DNA rep in somatic cells

Question 50

what increases the rate of mutations

Answer 50

mutagens

Question 51

silent mutations

Answer 51

neutra, in introns, incl del/ins

Question 52

nonsense

Answer 52

codon becoming stop codon instead of aa, prod shortened protein

Question 53

transcriptional level

Answer 53

alter conditions to allow RNA polymerase to bind

Question 54

post-translational level

Answer 54

modifying the polypeptides to mke proteins of specific functions

Question 55

post-transcriptional level

Answer 55

.