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Biology Topic 3 - Voice of the Genome > 3.1 - In the beginning > Flashcards

3.1 - In the beginning Flashcards

1
Q

What are the 10 features of a typical prokaryotic cell?

A
  1. ribosome
  2. circular DNA
  3. cell surface membrance
  4. cell wall
  5. cytoplasm
  6. flagellum
  7. pilli
  8. capsule
  9. plasmids
  10. infolding of cell surface membrane
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2
Q

What is the prokaryotic cell wall made up of?

A

contains peptidoglycan (a type of polysaccharide & polypeptide combined)

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3
Q

What is the role of a capsule in a prokaryotic cell?

A

slimy layer on surface for protection & to prevent dehydration

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4
Q

What is the role of a pili in a prokaryotic cell?

A

thin, protein tubes which allow bacterial cells (a type of prokaryotic cell) to adhere to surface

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5
Q

What is the role of the infolding of cell surface membrane in a prokaryotic cell?

A

site of respiration

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6
Q

What is the function of a ribosome?

A

site of protein synthesis

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7
Q

What is the function of the cell surface membrane?

A

controls what enters and leaves the cell

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8
Q

What is the function of the cytoplasm?

A

jelly-like substance where all the cell’s chemical reactions happen

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9
Q

What is the function of the cell wall?

A

provides structure to the cell

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10
Q

What is the function of the flagellum?

A

helps to move the cell

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11
Q

What are the 10 organelles in a typical eukaryotic cell?

A
  1. mitochondria
  2. nucleus
  3. nucleolus
  4. Rough endoplasmic reticulum
  5. smooth endoplasmic reticulum
  6. ribosomes
  7. cell surface membrane
  8. Golgi apparatus
  9. lysosome
  10. centrioles
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12
Q

What is the function of the mitochondria?

A
  • site of later stages of aerobic respriation
  • inner of its 2 membranes are folded to form finger-like projections called cristae
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13
Q

What is the nucleus contain?

*don’t say just DNA or genetic info

A
  • contains chromosomes & nucleolus
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14
Q

What are chromsomes made up of?

A

DNA, contains genes that control synthesis of proteins

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15
Q

What is the chromosomes and nucleolus enclosed in? What is it made up of?

A

envelope made up of 2 membranes pierced by pores

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16
Q

What is the function of centrioles?

A

involved in formation of spindle during nuclear division & in transport with cytoplasm

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17
Q

What are centrioles?

A

hollow cylinders made up of a ring of 9 nine protein microtubules

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18
Q

What is a specialised lysosome?

A

acrosome

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19
Q

What is the function of the nucleolus?

A

dense body within the nucleus where ribosomes are made

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20
Q

What is the rough endoplasmic reticulum?

A
  • system of interconnected membrane-bound, flattened sacs
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21
Q

What is attached to the outer surface of RER?

A

ribosomes

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22
Q

What is the function of the rough endoplasmic reticulum?

A

proteins made on attached ribosomes & are transported through the ER to other parts of cell

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23
Q

What are ribosomes made of?

A

made of RNA & protein, they are found free in the cytoplasm or attached rough ER

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24
Q

What is cell surface membrane/plasma membrane? What is its function?

A

phospholipid bilayer containing proteins & other molecules forming a partially permeable barrier

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25
What is the smooth endoplasmic reticulum?
- like rough ER, but without attached ribsomes - makes lipids & steroids
26
What is the golgi apparatus? What is its function?
- stacks of flattened, membrane-bound sacs formed by fusion of vesicles from ER - modifies proteins and packages them in vesicles for transport
27
What are the lysosome?
spherical sacs containg digestive enzymes & bound by a single membrane
28
What is the function of the lysosome?
- involved in breakdown of unwanted structures in cell & in destruction of whole cells, when old cell are to be replaced
29
Which 2 structures are sometimes present in an eukaryotic cell?
cilia & flagella
30
What happens in protein trafficking? (9 steps)
1. Transcription (in nucleus), of DNA to mRNA 2. mRNA leaves nucleus 3. proteins made on ribosomes enter through rough ER 4. proteins move through ER, adopting tertiary structure en route 5. vesicles pinched off rough ER contain protein 6. vesicles from rough ER fuse to form the flattened sacs of the Golgi apparatus 7. proteins are modified within the Golgi apparatus 8. vesicles pinched off the Golgi apparatus contain the modified proteins 9. vesicles fused with the cell surface membrane releasing proteins (such as extracellular enzymes & these extracellular enzymes will undergo exocytosis)
31
What is protein trafficking?
movements of proteins in a cell
32
Define fertilisation.
fusion of sperm nuclei & egg nuclei
33
How many chromosomes does a zygote contain?
46 (full no.)
34
What are the steps of the acrosome reaction?
1. sperm reaches egg cell & binds to zona pellucida 2. Acrosome swells & fuses with sperm cell surface membrane 3. Digestive enzymes in acrosome released 4. Enzymes digest a tunnel through follice & zona pellucida, so sperm can reach plasma membrane of egg cell 5. plasma membrane of sperm cell & egg cell fuse 6. sperm releases its nucleus into egg cell cytosplasm 7. nuclei of sperm & egg fuse
35
How are vesicles involved in the successful fertilisation of an egg cell by one sperm?
- cortical granules fuse with the egg cell membrane - this allows the enzymes to be released into the ZP to harden the ZP & prevent polyspermy
36
What is formed after fertilisation?
zygote
37
What are the adaptions of an egg cell? How does this mean they can carry out their function?
cytoplasm - contains nutrients for embryo growth lysosomes - thickens zona pellucida to prevent sperm entry follicle cells - form protective coating around egg cell zona pellucida - releases chemicals to attract sperm cell surface membrane - allows sperm to enter cell
38
Do sex cells contain one copy or two copies of chromosomes?
one copy
39
What are the 4 adaptations of a sperm cell? How does this it can carry out its functions?
flagellum - swim to egg cell streamlined shape - faster swimming body contains lots of mitochondria - provides ATP for movement head contains acrosome - filled with digestive enzymes to break down egg's ZP & allow sperm to reach egg cell membrane
40
What the type of gametes called before fertilisation?
haploid gametes
41
What does the cortical reaction prevent?
multiple sperm cells from fertilising egg
42
What is the process of the cortical reaction?
1. Fusion of sperm cell & egg cell cell surface membrane 2. Cortical granules release their contents (by exocytosis) into the zona pellucida 3. These contents react with the zona pellucia causing it to harden which prevents other sperm cells from entering 4. Sperm & egg cell nuclei then fuse
43
Does the cortical reaction occur before or after the acrosome reaction?
after
44
What types of cell divide by mitosis?
all cells other than gametes
45
What is meiosis?
cell division that results in productions of 4 haploid nuclei
46
Do gametes divide by mitosis or meiosis?
meiosis
47
What is a fertilised cell described as?
diploid zygote
48
Does meiosis produce genetically identical or different cells?
genetically different
49
What does meiosis lead to?
genetic variation among offspring
50
What are the 2 ways that crossing over can lead to genetic variation?
- crossing over - independent assortment
51
When does crossing over occur?
meiosis 1
52
What happens during crossing over?
- homologous chromosomes come together as pairs & all 4 chromatids come into contact - at these contact points, chromatids break & region exchanging sections of DNA between non-sister chromatids
53
What is the point when chromatids break called?
chiasmata
54
How does crossing over lead to genetic variation?
many chiasmata may form anywhere along length of chromsome, leading -> chromosomes containing new combinations of alleels from both parents
55
Does crossing over occur between sex chromosomes occur?
no
56
When does independent assortment occur?
occurs during meiosis 1
57
What happens during independent assortment?
- each gamete ends up w only one of homologous pairs of chromosomes - independent assortment of chromosomes as they line up during meiosis is random & either chromosome from each pair could be in either gamete
58
What does independent assortment mean for the gametes?
gametes can end up with many diff. combinations of maternal or paternal chromosomes
59
Why is genetic variation important?
enables some individuals to adapt to environment while maintaining survival of population
60
Other than independent assortment & crossing over, what else can lead to varition?
random fertilisation
61
What is random fertilisation?
where it is completely as to which sperm will fertilise egg
62
Where does meiosis occur?
in reproductive organs
63
What is a chromatid?
identical half of the copied chromosome
64
What are centromeres?
region where 2 chromatids are joined at
65
What are the steps of the acrosome reaction?
1. sperm reaches egg cell & binds to zona pellucida 2. Acrosome swells & fuses with sperm cell surface membrane 3. Digestive enzymes in acrosome released 4. Enzymes digest a tunnel through follice & zona pellucida, so sperm can reach plasma membrane of egg cell 5. plasma membrane of sperm cell & egg cell fuse 6. sperm releases its nucleus into egg cell cytosplasm 7. nuclei of sperm & egg fuse
66
How many homologous pairs of chromosomes does a human have?
22
67
How many pairs of sex chromosomes does a human have?
1
68
How many singular chromosomes does each gamete contain?
23
69
What is a cell called when it contains 1/2 the full number of chromosomes?
haploid
70
What is a cell called when it contains the full number of chromosomes?
diploid
71
How many singular chromosomes are contained in a zygote?
46
72
Why may a chromosome show weak linkage?
genes are furthest apart so more likely to be separated during crossing over
73
What is a gene mutation?
change in base sequence of a gene
74

Biology Topic 3 - Voice of the Genome (4 decks)

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