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topic 3 bio Flashcards

1
Q

microscope equation

A

a=i/m

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2
Q

state the 4 stains in microscopes and tell where its used and its colour

A

haemotoxylin - stains the nuclei of plant and animal cells
(purple, blue, black)

methylene blue - stains the nuclei of animal cells (blue)

acetocharmine - stains the chromosomes in diving nuclei in both plant and animal cells

iodine - stains starch (blue black)

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3
Q

describe the two types of eletron micrographs

A

transmission electron micrograph - 2D images similar to those from a light microscope

scanning electron micrograph - hve lower magnification, 3D, very striking

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4
Q

define ultratrustures

A

structures in cells that can only be obserbed thru n electron mciroscope

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5
Q

describe the envelope in an animal cell and wt is it made of

A

its the double membrane that has pores which enables molecules to enter and leave the nuclues. its madeof proteins and nucliec acid

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6
Q

describe the strucutre of the mitochondira

A

it has an outer and inner mebrane. the inner membrane is folded to form cristae which gives it a large surface area. it has its own genetic info

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7
Q

what happenes to the centrioles during cell division

A

the cnetiroles will pull apart to produce a spindle of microtubules that r involved in the movement of chromosomes

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8
Q

describe 80s rhibomsomes

A

Found in eukaryotic cells (plants, animals, fungi, protists).
Larger in size (~25-30 nm).
Composed of 60S & 40S subunits.
Function: Protein synthesis in eukaryotic cells.

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9
Q

describe 70s rhibomes

A

Found in prokaryotic cells (bacteria & archaea).
Smaller in size (~20 nm).
Composed of 50S & 30S subunits.
Function: Protein synthesis in prokaryotic cells.

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10
Q

function of lysosomes

A

fuse with outer cell membrane to release its enzymes outside the cell as extracelular enzymes

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11
Q

wt is apoptosis

A

when the cell gets too old, the lysosomes self destructs

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12
Q

describe RER

A

covered in 80s rhibosomes granules.
has a large surface area for the synthesis of proteins
stores and transprots the proteins, and synthezies

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13
Q

describe the SER

A

synthezises and trnapsorts steroids and lipids

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14
Q

describe the golgi aparatus and its function

A

a series of fluid filed, flatenned sacs with vesicles surrounding the edges.
processes and packages proteins and lipids, it also produces lysosomes

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15
Q

descirbe grtam stain

A

has a crytsal violet colour

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16
Q

why doesnt the gram positive bacteria pick up the red safranin counterstain and appaear purple when in a light microscope

A

cuz gram positive bacteria has a thick layer of peptidoglycan that has teichoic acid. the crytal violet complex in the gram stain is trapped in the peptiglocygan layer and resits decoloruing when the bacteria is dehydrated. as a result bacteria doesnt pick up the red safranin counterstain and appears puple instead

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17
Q

why is it possible for the gram negative bacteria to take up the red safranin counterstrain

A

cuz it has a thin layer of peptidoglycan with no teichoic acid and the outer membrane is made is lipopolysacharides which gets dissvled when bacteria is dehydrated. this exposes the thin peptidoglycan layer and the crystal violet is washed out and the peptidoglycan wud take up the red safranin counterstain.

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18
Q

define asexual reproduction

A

production of genetically identical offspring from a single parent

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19
Q

give two of mitotic cell division

A

asexual reproducition and cell growth

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20
Q

define homologous pair

A

a set of two chromosomes, one inherited from each parent

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21
Q

wt is a chromosome made out of

A

coiled threads of DNA
proteins

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22
Q

how can DNA molecules be packaged efficinetly during the condesning of DNA molecules

A

with the help of histones. the dna winds around the histones to create nucleosomes, theseinteract to produce more coiling and then becomes denser

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23
Q

define karyotype

A

an individual’s complete set of chromosomes

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24
Q

describe the cell cycle

A

interphase - the cell grows, chrosomes replicate and become double stranded chromatids, organelles and other material needed for cell division is synthesised
mitosis - when the nucles is actively dividing
cytokenisis - cyclins build up and attach to cyclin dependent kinases. new cells seperate

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25
wt r the stages in mitosis in order
prophase metaphase anaphase telophase
26
wt happens during prophase
chromosomes coil up and take up stains to be visible. at this point each chromosomes has two daughter chromatids that r attached to each other at the centromere. nucleoloues breaks down and centrioles pull apart to form the spinde
27
prophase diagram
https://images.app.goo.gl/dkjHeu8bmXhLN3NU8
28
wt happens during metaphase
the chromatids compete for a position on the equator of the spindle. they line up along this posiiton.
29
metaphase diagram
https://images.app.goo.gl/kFqd26AwCXP3qoga9
30
wt happens during anaphase
the chromatids from each pair are pulled towards opposite poles of the cell.
31
anaphase diagram
https://images.app.goo.gl/6srY3wkPSDCKD47L7
32
wt happens in telophase
spindle fibres break down and nulear envelopes form around 2 sets of chromosomes. the nuclei and centrioles are also re-formed. the chromosomes begin to unravel and seperate becoming less dense
33
telophase diagram
https://images.app.goo.gl/wpzKcncmJQ2WY1386
34
wt happens in cytokenisis in animal cells
a ring of contractile fibres tightens around the centre of the cell. they continue to contract until the two cells hve been seperated
35
wt happens in cytokenisis in plant cells
a cellulose cell wall builds up from the inside of the cell outwards
36
cytokenisis in animal and plant cells diagram
https://images.app.goo.gl/89zY7tVx9QULuTZ98
37
uses of mitosis
grow and replcace old cells for asexual reproduction
38
adv and disadv of asexual reporudction
adv - only needs one parent so no need a mate large no of offpsinrg disadv - all offspring geneticaly identical so diseases can kill them easily
39
mitotic index equation
cells in mitosis/total no of cells
40
define chromatid
one of the two identical halves of a chromosome that has been replicated in preparation for cell division
41
wt r gametes formed from
meiosis
42
explain wt happens in prophase 1
prophase I - each chromoosme appears in the condesed form with two chromatids. crossing over happens
43
wt happens in metaphase 1
spindle forms and the pairs of chromosomes line up of the equator
44
wt happens in anaphase 1
one chromosome from each homologous pair moves to the end of the cell, and chromosome no becomes half
45
wt happens in telophase 1
nuclear membrane reform and the cells divide.
46
wt happens in prophase 2
new spidles r formed
47
wt happens in metaphae 2
the chromosomes line up of the equatorwt
48
wt happens in anaphase 2
the centromeres now divide and the chromatids move to the opposite ens of the cellw
49
wt happens in telophase 2
nuclear envelopes reform, the chromoomes reutrn to their interphase state and cytokenisis occurs, giving four daughter cells with half od the chromosome no
50
diff between mitosis and meiosis (3)
(purpose)= mitosis-Growth, repair, and asexual reproduction meiosis - Formation of gametes (Daughter Cells Produced)= mitosis - 2 meiosis - 4 mitosis - diploaid meisos - haploid
51
similarities between mitosis and meiosis (4)
Both start with a diploid parent cell. Both involve DNA replication before cell division Both involve spindle fibers and centrioles for chromosome movement. Both are types of cell division processes.
52
importance of meiosis
crossing over independant assortment-gametes
53
wt do u call the process that makes gametes
gametogenisis
54
during gameotigensis describe the roles of mitosis and meiosis
mitosis- provides the precursor cells meiosis-causes the reduction of genetic material in divions
55
3 functions of sperm
must carry genetic info must remain is semen so it can be transported must penetrate protective barrier using enzymes from acrosome
56
wt r the two phases in a plants life cycle
saprophyte generation gametophyte generation
57
descirbe sporophyte generation
is diploid and produces spores by meiosis
58
describe gametophyte generation
is haploid and produces gametes by mitosis
59
wt do u call male gametes in plants
microgametes
60
wt r the two haploid nuclei that each pollen grian consits
tube nuclues and generative nucles
61
function of tube nuclues and generative nuclues
tube nuclues-function of producing a pollen tube that penetrates thru sigma, style and ovary into the ovule generative nucleus-fuses with the nuclues of the ovule to form a new infividual
62
wt does a combination of meiotic and mitotic cell division result in
an egg cell caled megagamete
63
wt r the ways that animals use to make the gametes meet
external fertilisation internal fertilisation
64
descibe external fertilisation
when trhe female and male gametes discharged directy into the environment where they meet and fuse
65
describe internal fertilisation
transfer of male gametes directly into the female,
66
describe the acrosome reaction
enzymes r released from the acrosome which digest the follicle cells aroudn the zona pellucida.
67
wt is polyspermy
fertilisation by more than one sperm
68
describe cortica reaction
ovum releases enzymes to the zona pellucida that thickens the zona pellucida
69
describe fertilisation in plants
pollen is transfered from the anther to the stigma. pollination happens by either wind,insects,birds,water. once the pollen grain lands on the stigma it germinates. the pollen tube grows down the style to the ovary. the tip of the pollen tube produced hydrolytic enzymes to digest the tissue of the style. thr generative nuclues divids by mitosis. once the tube enterd the micropule, ferlisatin happens
70
wt do plants do to prevent self fertilisation
the pollen grain will only germinate if its from the same species but a diff plant
71
describe conttinous and discountionus variables and give exs
continous - variables within a range and are measurable. ex - height weight, temp discountinous - these variables have distinct, separate categories with no intermediate values. ex - blood grp, eye colour, ability to do smthn
72

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