Revision Flashcards
1
Q
Key factor limiting maximal cell size
A
Surface area to vol ratio
2
Q
Differences betweeen prokaryotic and eukaryotic cell
A
prokaryotic cells do not have membrane-enclosed organelles
3
Q
common feature between prokaryotic and eukaryotic cell
A
plasma membrane, DNA, ribosomes
4
Q
Why does rough ER appear ‘rough’
A
presence of ribosomes on ER membrane surface
5
Q
What is stored in animal nucleus
A
Chromosomal DNA
6
Q
Order of compartments in endomembrane system
A
ER → golgi →lysosome
7
Q
Organelle where lipids are synthesised
A
smooth ER
8
Q
Golgi functions
A
- sort and distribute cargo derived from the ER
- both absorb/merge with and release transport vesicles
- process sugars added to proteins and lipids added in the ER
9
Q
Vesicles leaving transface of Golgi may go to:
A
the plasma membrane, vacuoles, lysosomes
10
Q
function of nucleolus
A
site of ribosome synthesis and assembly
11
Q
Shape of inner membrane of mitochondria
A
inc. surface area to volume ratio →more energy
12
Q
A cells plasma membrane
A
- is selectively permeable
- flexible
- fluidity
13
Q
define - Selectively permeable
A
allows some molecules through by passive or active transport
14
Q
phospholipid
A
polar head group and non polar fatty acid rail
15
Q
increasing level on unsaturated fatty acids in phospholipids
A
- increase membrane fluidity
- decrease viscosity
16
Q
Organism membranes at colder temps
A
more phospholipids with unsaturated fatty acid tails
17
Q
Facilitated diffusion does not require
A
energy expenditure
18
Q
What molecules are most likely to diffuse through a cells plasma membrane
A
Small non-polar
19
Q
Active transport
A
- can move molecules against their concentration gradient
- requires energy to be expended
20
Q
osmosis
A
when water molecules move from high to low concentration across a plasma membrane
21
Q
Hypertonic
A
solute concentration outside a cell is higher than inside.
22
Q
exocytosis
A
Form of active transport where eukaryotic cells transport proteins out of the cell
23
Q
phagocytosis
A
form of active transport which amoeba ingests a bacterial cell such as paramecium
24
Q
forms of potential energy
A
- chemical bond energy
- ion gradient across a membrane
- ATP
25
1st law of thermodynamics
energy is never created or destroyed but can change forms
26
exergonic
reactions that are spontaneous in living systems
27
spontaneous reactions may not by instantaneous
bc even exergonic reactions may require activation energy
28
activation energy
initial energy needed to start a chemical reaction
29
enzymes
- biological catalysts
- specific for their substrates
- are proteins
30
competitive inhibitors of biochemical reactions bind to an enzymes
active site
31
biochemical pathway regulation
negative FB control involving end products inhibiting early steps
32
Glycolysis takes place in
cytosol
33
Kreb's/TCA cycle occurs in
mitochondria matrix
34
during full aerobic respiration of glucose to CO2, most ATP is produced directly by
the mitochonrial electron transport chain
35
if individual has defective mitochondrial energy production, muscles/cells are likely to:
- accumulate NADH
- rely more on glycolysis for energy production
- accumulate lactic acid
36
most direct source of energy used to power the mitochondrial ATP synthase
proton gradient across the inner mitochondrial membrane
37
molecule that stores genetic info in cells
DNA
38
double stranded DNA held together by
hydrogen bonding between A and T; G&C
39
DNA replication makes
a copy of DNA using one strand of DNA as a template
40
DNA replication occurs in which direction
5' to 3'
41
Okazaki fragments generated during
lagging strand DNA replication
42
Absence of telomerase activity
telomeres would get shorter w/ each round of replication
43
prokaryotic transcription produces
mRNA, tRNA, rRNA
44
order of events startingfrom gene
DNA → pre-mRNA → mRNA → polypeptide
45
for pre-mRNA to be processed into mRNA
introns need to be removed
46
in eukaryotes where to transcription and translation occur
transcription (nucleus), translation (cytoplasm)
47
what determines the order of amino acids in a protein
order of nucleotides in the DNA of the transcribed strand
48
what specifies an amino acid during translation
a codon
49
some codons specify
a start signal for a ribosome
50
a missense mutuation leads to
changes the amino acid being added during translation
51
process of transcription
Info in DNA being converted into RNA
52
gene expression describes process where
genetic information is used to produce proteins/RNA
53
prokaryotes control of gene expression usually occurs at
initiation of transcription
54
function of RNA polymerase
to transcribe genes into RNA
55
promoter
RNA polymerase bind to this region of DNA to initiate transcription
56
Function of promoter needed for DNA sequence
- binding of RNA polymerase & initiation of transcription
- potential binding site of transcription factors
- positioning of RNA polymerase with respect to gene start site
57
how does lacl repressor alter expression of genes
lacl binds the lac operon promoter and blocks transcription
58
binding of the lac repressor to the promoter of lac operon
prevents RNA polymerase from initiation transcription
59
why muscle cells are different from kidney cells
they express different specific transcription factors
60
cell division used by bacterial cells
binary fission
61
What stage of the eukaryotic cell division is DNA replicated
S- phase
62
After DNA replication, what are the names given to the chromosomal structures formed
sister chromatids
63
a diploid cell undergoes mitosis. the two cells produced will
both be diploid and genetically identical
64
during mitosis
sister chromatids are held together until anaphase
65
in metaphase of mitosis the kinetochores of each sister chromatid are
bound to microtubules from separate spindle poles
66
how are sister chromatids held together during mitosis
cohesin
67
in anaphase, separation of sister chromatids is achieved by triggering
- movement of sister chromatids to opposite poles
| - destruction of cohesin
68
function of the G1/S checkpoint of the cell cycle
desicion to initiate a round of cell division
69
why is metaphase/anaphase (spindle) checkpoint so important
- cell checks proper attachment of chromatids to spindles
- it is an irreversible step in mitosis
- errors can lead to cells with abnormal number of chromosomes
70
what disease is associated with cells losing control of cell division cycle
cancer
71
primary role of meiosis
to generate gametes with one set (half) of chromosomes
72
in humans, meiosis is conducted in:
only in germ-line cells
73
during prophase I of meiosis
- homologous chromosomes become closer associated/paired
| - synapsis occurs
74
crossing over of chromosomes in meiosis I only occur in
homologous chromosomes
75
during mitosis
- homologous chromosomes do not pair via synapsis
- sister chromatids are separated during anaphase
- crossing over does not occur
76
during anaphase I of meiosis
homologous chromosomes are separated
77
chromosome nondisjunction
failure to separate homologous chromosomes/ sister chromatids
-occur in either or both meiosis I or II
78
name given to describe genes affecting a trait
genotype
79
what describes an organisms appearance or observable characteristics of a trait
phenotype
80
different DNA sequences or forms of same gene
allele
81
in a diploid organism for the recessive trait to be expressed the individual must be
homozygous recessive
82
what was not part of mendel's five-element model
if an allele is present it will be expressed
83
incomplete dominace is a situation where the phenotype of heterozygote is
between the homozygous dominant and homozygous recessive
84
in humans, X & Y chromosomes
- have many genes only found on one not both
- are homologous
- determine sex & have genes unrelated to sex teremination
85
in terms of sex-linked traits males are often
more likely than females to express recessive traits
86
since women have two X chromosomes and males 1, females
can be carriers of x-linked traits
87
If a mother has the x-linked trait haemophilia has children
all of her sons will have haemophilia
88
If a father has hemophilia and the mother is neither a carrier nor has hemophilia
half of their daughters will be carriers
89
in each female cell, one x-chromosome
is inactivated by condensation into a bar body
90
if a female is heterozygous for a recessive allele for sweat glands on the x-chromosome
some patches of skin will have sweat glands some wont
91
if a male has a recessive allele for sweat glans on the x-chromosome
none of his skin will express sweat glands
