Basic Cell Structure Flashcards
(253 cards)
1
Q
what are macromolecules and the types of biological molecules
A
macromolecules are polymers made long chain of monomer subunits
Lipids, carbohydrates, proteins and nucleic acids
2
Q
Types of lipids
A
Triacylglycerol - made of glycerol and 3 fatty acids through dehydration reaction,, used to store fat in the body
Phospholipids - used to form membranes in different part of the cell
3
Q
What are lipids made of?
A
Fatty acid monomers
4
Q
Structure of the plasma membrane
A
Consist of phospholipid bilayer with hydrophobic and hydrophillic region (amphipathic),, contain other macromolecules within the structure such carbs for recongization and protection, and protein to maintain the shape and allow selective passage
5
Q
Why is there an amphipathic regions?
A
Due to the hydrophilic group consisting of phosphate, that is also negatively charged and polar
While hydrophobic is uncharged and non polar
6
Q
What means by amphipathic molecules?
A
Contain both polar + charged (hydrophillic) and non polar + uncharged(hydrophobic)
7
Q
What is fluid mosaic model
A
Structure of cell membrane as a flexible structyre made of proteins and lipids
8
Q
why is it called fluid moisaic model
A
due to the fluidity from the amphipathic bilayer and the mosaic from the proteins embedding in the membrane
9
Q
Functions of the cell membrane
A
- Encloses and protects the cell contents
- Barrier between the inside and outside of the cell
- Different chemical environment can exist on each side
- Selectively permeable as they allow certain molecules through and block the movement of others - Provides and support mechanical struture
- Through cytoskeleton to maintain the shapw
- extracellulear matrix - defines and encloses the cell
- membrane allows the cell to control the internal pressure and concentrentations of the intrecellular components - Transport in and out of the cell
- allow specific molecules acrpss the cell membranes in either direction
- passive transport: through diffusion across the membrane from high concentration to low concentration (concentration gradient) without energy
- active transport: molecules are pumped actoss the membrane against the concentration gradient (low concentration to high concentration), require energy
- bulk transport:
endocytosis,, molecules are taken in when the plasma membrane pinches inwards forming a vesicle (bubble)
exocytosis,, molecules are secreted when vesicle fuses with the plasma mebrane
10
Q
what are the transportation means of molecules in cell membrane
A
- active
- passive
- bulk - exocytosis
- bulk - endocytosis
11
Q
differences between eukaryotes and prokaryotes
A
eukaryotes:
- multicellular
- linear dna
- membrane- bound organelles
- contain nucleus
- mitosis
prokaryotes:
- unicellualr
-circular dna
- lacking membrane-bound organelles
- lack nucleus
- binary fission
12
Q
similarities between eukaryotes and prokaryotes
A
- plasma membrane
- cell division
- cytoplasm
- ribosomes
13
Q
components in eukaryotes and prokaryoes
A
^^
14
Q
what is endosymbiosis
A
The process which prokaryotes cells adapted to become eukaryotic cells (mutuially ebneficial relationship)
the theory is asscociated witht he origin of eukaryotic cells and the evolution of organelles such as mitochondria and chloroplasts
host cell engulf free-living bacterium
mutualism
integration as it becomes more dependent on the host cell and specialized for its specific functions
evolve into specializedd organelles
15
Q
unsaturated vs saturated hydrocrabon tails
A
- unsaturated due to cis double bond taht prevents packing, thus increase membrane fluidity
- saturated due to trans bond that keeps it pack together thus less flexible and more rigid
chloresterol (lipid) are embedded in between the layers that reduces membrane fluidity and hinders solidification ajd disrupt the regualr packing
16
Q
what happen in diffusion with one solute vs two solute
what happen in osmosis
A
net diffusion until equilibrium on both sides
osmosis moves from high free water concentration to low free water concentration
17
Q
what is tonicity
A
the ability of surrounding solution to cause a cell to gain or lose water (pressure)
18
Q
hypotonic vs isotonic vs hypertonic solution
A
hypo - too much water intake,, too much internal pressure
isotonic - balance pressure
hyper - too much water loss,, too much external pressure
19
Q
how the active transport works
A
specific molecules bind to the shape in the carrier protein channel
energy is supplied by atp hydrolysis
20
Q
role of carbs (polymer)
A
- source of energy
- structural support
21
Q
role of proteins (polymer)
A
- catalyse reactions
- transport substances in and out of cell
22
Q
role of nucleic acid (polymer)
A
- contain dna information
- function in gene expression
23
Q
role of lipids (not polymer)
A
- provide energy
- making up cell membranes
- act as hormones
24
Q
chemical formula and structure
A
^^
25
what is the bond called for the formation lipid
ester bond (dehydration reaction) between fatty acid and glycerol
26
what are the 3 chemical properties different between tag and phospholipids
- no of fattyu acids
- ampipathic nature of phospholipids
- hiogh energy density dur to higher fatty aicds thus higher potential energy released
27
How synthesis of polymers works
monomers form larger molecules (polymers) through polymerisation
linking monomers together via dehydration reactions (removal of water molecule)
28
how breakdown of polymers works
polymers are shortned by removing monomers from either end via hydrolysis (addition of water molecule)
29
what is the monomer and polymer for carbs called?
monomer: glucose
polymer: glycogen
30
structure pf glucose
^^
6 carbons
31
what is the bond called for carbs polymer
glycosidic bond
32
what is the glycosidic bond called for branched polymer
(1, 6) glycosidic bond
33
what is the glycosidic bond called for straight polymer in carbs
(1, 4) glycosidic bond
34
what is the monomer and polymer cakked in proteins
monomer: amino acids
polymer: polypeptides
35
what is the struture of proteins
^^
consist of carboxyl and amino groups and a carbon (backbone)
varied in R group (side chain)
36
what are the properties of r group
- non polar
- polar
- charged (acidic)
- charged (basic)
37
what are the bonds called in proteins
peptide bond
38
what are the levels of protein structure
1. primary structure - amino acids are in linear chain
2. secondary structure - linear chain is stabilized by hdrogen bonds to form either alpha-helices or beta-sheets
3. tertiary struture - further stabalize to form 3d structure of proteins through covakent and non covalent bonds
4. quartenary structure - two or more polypeptides
39
how enzyme varied in their specificity
determine by protein structure
vary in shape and active site
lock and key modle
induced fit model
40
how enzyme play a role in the process of cellualr energy
it catalyze process thus lowers the activation energy thus more likely to proceed
41
what is activation energy barrier
it prevetns the reactions tp proceed as soons as the reactants are present
42
Where are proteins found in bacterial cells
all metabolic reactions (ie. energy generation, protein synthesis, dna replication, synthesis of cell components) occur in the same space (ie. the cytoplasm or in cell membrane)
43
where are proteins found in the eukaryotic cells
proteins are translated at ribosomes embedded in the endoplasmic reticulum which will be further modify int eh golgi body
cytoplasm where there are free ribosomes for protein synthesis
ribosomes for protein syntehsis can also be found in mitochondria and chloroplast
44
what happpens in mitochondria
it is a site of respiration (process of converting nutrients into ATP) in both animal and plant cells
They have 2 membranes where one is smooth and another is folded, cristae
ribosomes are found in the matrix within the cristae compartment
They have their own dna and ribosomes to make their own proteins
45
what happens in chloroplasts
found only in plant cells
contain chlorophyll, site for photsynthesis
they have 3 membranes (outer, inner, and thylaakoid)
inner is where ribosomes are found
46
Use of sytoskeleton in the eukaryotic cell
made up of protein
essential to maintain cell shape, provide support, and cell movement
47
what are the three types of cytoskeleton structure
microtubules (rigid), microfilaments (semi flex), intermediate filaments (flexible)
48
what is 1 unit of carbohydrates called
monosaccharides, ie glucose
49
what are 2 unit of carbohydrates called and its bond called?
maltose with 1,4 glycosidic bond
50
what is many units of carbs called and examples and its type of bond called
polysaccharides, 1, 4 and 1,6 glycosidic bond, with starch, glycogen and cellulose
branching of the glucose with 1,6 glycosidic bond
51
why human can digest starch and glycogen and not glucosee?
starch and glycogen is in the alpha configuration and human have the specific enzyme for it as compares to in cellulose with beta configuration
52
what is the difference between alpha and beta configuration of carbs
alpha has its OH group below while beta has its OH group above
53
what is glycemic index
measure how easily food is digested and how quickly glucos enters the bloostream
54
what is glycogenprotein adn chitin
- made up of carbohydrates and proteins,, used as an identifying markers on cell, found on the cell surface
- a tough layer , resistant to enzyme degradation
55
why eating sushi containing amylopectin raise blood sugar more than amylose
amylopectin is highly branched thus be digested more quickly and raising the blood glucose level higher than amylose
56
what is teh enzyme that digest alpha configuration in carbs
alpha - amylase
57
why highly branched polysaccharides is digested more quickly than a linear chain
- in a highly branched structure, there are more sites where the enzyme can initiate hydrolysis, allowinf for efficient digestion
- higher surface are for enzyme to bind thus rapid breakdown
58
what are the bonds called in tag
ester linkage
59
difference in charge and polarity impact on the protein structyure
charge can have a significant impact on specific interactions within a protein, polarity often has a broader influence on the overall protein structure and stability
60
why polarity impact is broader in protein structure as compared to charge which is more localized?
- charge can have a significant impact on specific interactions within a protein, polarity often has a broader influence on the overall protein structure and stability
- charge can have a significant impact on specific interactions within a protein, polarity often has a broader influence on the overall protein structure and stability
61
influence of r group and backbone on the protein structure respectively
charge can have a significant impact on specific interactions within a protein, polarity often has a broader influence on the overall protein structure and stability
62
what is energy
energy is the capacity to do work
63
what is energy conversion in organism
process of transformin one form (mostly as potential energy) to another with vast majority loss as heat
64
what is energy conversion in organism
process of transformin one form (mostly as potential energy) to another with vast majority loss as heat
65
define gibbs free energy (G)
amount of energy in a system taht can be used to do work wile pressure and temperature are constant
66
what is the formula for change in G
ΔG = Gfinal - Ginitial
67
what is the formula for change in G
ΔG = Gfinal - Ginitial
68
what is metabolism
it is the sum of all chemical reactions (energy conversion) that occur within an organism to maintain life
69
what is the 2 process in metabolic reactions
- catabolic reaction, neg ΔG,, break down bond, release energy
- anabolic reaction, pos ΔG,, synthesize bond, consume energy
70
what is formula for meatbolism
metabolism = catabolic + anabolic reactions
71
what is neg chnage ΔG called
exergonic reaction
72
whta is pos chaneg ΔG called
endergonic reaction
73
what is the groah for exogornic and endogornic reactions?
^^
74
what is the benefit of activation energy barrier
- control of reaction rate
- selective reactions
- energy efficiency
75
min 3 difference in endergonic and exergonic (terms: disorder [n why?], total energy in system and spontaneous)
exergonic: increase disorder (entropy), decrease total energy, spontaneous
76
use of atp in cellullar energy
it helps store energy
77
use of adp
intermediate for enrgy transfer
78
how energy is stored in atp
chemical energy, from food/nutrients breakdown, is stored in the bonds between 3 phosphate groups
79
the reaction in ATP synthesis and hydrolysis (term: exergonic, endogornic)
atp --> adp: atp hydrolysis, release energy to become adp
adp --> atp: atp synthesis, consume energy to become atp
80
what is the difference in phosphate group in atp and adp
atp: 3,, adp: 2
81
how atp hydrolysis ar ebale to release energy (term: expense, release)
cost of energy to break the bond is investment to break the tension between the negatuvely charges phosphate groups, which will release high potential energy from atp to adp
82
what is coupled reaction
cell reactions require exergonic that release engy to provide energy for endegornic taht consume energy
83
why and how couple reactions need to control energy loss
highly controlled to manage the amount of energy released through release in small steps and minimise any wated energy, throughrelying on intermediate electron shuttle carriers to accept some of these electrons and protons, as these are need for electron transport chain in atp synthesis
84
what are the electron shuttle carriers
(reduced form)
- nadh
- fadh2
85
how electron carrier plays a part in atp syntehsis
atp = nadh +fadh (as both can release elctrons for atp synthesis)
86
formula of hydrgen ion concentration (H+), a proton, referring to pH
pH = -log[h+]
87
why h+ cannot freely diffuse across membrane
charged ion, thus need channel for transfer as it is The lipid bilayer is primarily composed of hydrophobic fatty acid tails, which create a barrier to the passage of hydrophilic substances like ions. While H+ ions are small, they still have a strong affinity for water due to their high charge density
Thus amphipathic layer repels the charges
88
what is cellular repiration
process that breaks down organic molecules to produce energy in the form of ATP
89
what are the 3 process in celular respiration
1. glycolysis
2. pyruvate oxidation and citric cyle (produce mostly nadh and little atp)
3. oxidative phosphorylation (produces lot of atp)
90
what happen in glycolysis
- occur in cytoplasm
- glucose --> 2 molecules of pyruvate
- produce 2 NADH and 2 ATP
91
what happen in pyruvate oxidation
- occur in the mitochondrion
- pyruvate --> acetyl-CoA _ CO2
- 1 NADH
92
whta happen in citric acid cycle
- occur in mitchondrial matrix
- acetyl-CoA --> CO2
- produce 2 FADH2, 1 ATP, 6 NADH
93
what happen in oxidative phosphorylation
- produces 26 - 28 atp
1. electron transport chain (exegornic)
- occur in the inner mitochondrial membrane
- nadh and fadh2 donate their high energy electrins to the electron transport chain
- as electrons move through the etc, they release energy which is used to pump protons (H+) across the membran, creating proton gradient
2.chemiosis (endegornic)
- the proton gradeint generated by the etc drives atp synthesis as proton flow back into the mitochondrial matrix due to the need for H+ ion/proton equilibrium
94
what happen in oxidative phosphorylation
1. electron transport chain
- nadh and fadh2 donate their high energy electrins to the electron transport chain
95
role of oxygen in etc
all the release electrons to drive the protein complex will be transferred to the oxygen at the end of the chain to become water
this reduce buils up of electrons which otherwise will cause inability to regeneare NAD+ and FAD as it cannot go back to its reduce form for the etc
help maintain proton gradient
96
what is the maximum atp per glucose?
30 to 32
97
reaction of cellular respiration
oxygen + glucose --> water + energy + co2
98
what are the ratio of oxygen to glucose for cellular respi
1 molecule of glucose to 6 molecules of O2
99
why atp is a nucleotide
consist of adenine. robose and 3 phosphate grp
100
how much protons require for a atp molecule
3
101
What are the 3 formula in determining conc and dilutions
1.
Mole = 6 x 10^23 molecules
Molecular weight ( MW) = grams / mole of compound
Number of moles = weight (in grams) / molecular weight
2.
Concentration (molarity, M) = no of moles/ vol
3. Conc1 x vol1 = conc2 x vol2
102
What is bond called between phosphate grpup
Phosphoanhydride bond
103
How proton gradient is used for atp synthesis
Through passive means, it flows throught he atp synthase, a protein channel, which uses the potential energy release to make 1 atp
104
How to check h+ gradient?
By checking pH
105
What is the cell division in prokaryotes called
Binary fission
106
What is the cell divison in eukaryotes called
Mitosis and meiosis
107
Which direction does rna polymerase moves on the template strand and direction of making the mRNA
3 to 5
mRNA from 5 to 3
108
What direction does the DNA polymerase reads the mRNA to make new DNA strand
3 to 5
109
Where dna replication occurs
Replication fork
110
What is the orientation feature of dna strand
Anti parallel
111
What is the orientation feature of dna strand
Anti parallel
112
What are the 4 molecules that helps replication fork
1. Helicase
- unwinds the dna double helix but increases coiling (at the open space) ahead of the replication fork
2. Topoisomerase
- relieve tension and supercoiling that occur ahead of the replication fork as dna unwind (at the close space after the open space)
3. Single strand binding protein
- stabalise the unwound strands, preventing them from reannealing and degradation
4. Dna primase
- polymerase to synthesize short rna primer
113
What goes on in leading strand synthesis
1. Dna primase synthesize short rna primer
2. Dna polymerase iii extend rna primer
3. Rna primer is removed by rna polymerase i and replaced with dna
114
What goses on in lagging strand synthesis
1. Rna primer is repeatedly made, thus lots pf dna fragements knwon as okazaki fragments
2. Dna pol iii add nucleotides to a primer and detaches when reach the next primer, starting with further from replucation fork
3. Dna pol 1 replaces rna with dna
4. Dna ligase joins the olazaki fragemnts to make a continous dna strand
115
Term when dna condense and packaged
Chromosome
116
Difference between a unduplicated chromosomes and a duplicated chromosome
Unduplicated: has 2 chromosome arms connected at the centromere
Duplicated: has 2 duplicated sister chromatids, thus double the dna
117
Why eukaryotic cell cycle is impt
It is important for the growth, development and reproduction of eukaryotes organisms
As the cycle starts, all other activities are put on hold
118
What does eukaryotic cell cycle consist of
1. Mitotic (shorter period)
- mitosis , divison of nucleus
- cytokinesis, division of cytoplasm
2. Interphase (longer period)
- gap 1, normal cell metabolism, grow in size and synthesize the necessary proteins
- s, dna replication
- gap 2, preparation for cell division, chexkibg for errors
119
What happen in interphase g2 before mitosis
Dna is duplicated
Still in chromatin form
120
What are the steps in mitosis
Prophase
Prometophase
Metaphase
Anaphase
Telophase
121
What are the steps in mitosis
Prophase
Prometophase
Metaphase
Anaphase
Telophase
122
What happen in prophase
Dna condense to form chromatin
Centrosome divides aloong with microtubules to form mitotic spindle
123
What happen in prophase
Dna condense to form chromatin
Centrosome divides aloong with microtubules to form mitotic spindle
124
What happen in prometaphase
Micrptubules bind to the kintochores
Chromosomes anchored to the mitotic spindle
Nuclear membrane degrades
Centrosome moves to opposite poles of cells
125
What happen in metaphase
The mitotic spindle moves the chromosomes to the middle of the cell
126
What happen in metaphase
The mitotic spindle moves the chromosomes to the middle of the cell
127
What happen in anaphase
The micrptubules pull the sister chromatis apart to opposite end of the cells
128
What happen in telophase
Two sets of chromosomes are seperated
Cells split into two forming cleavage furrow
Nuclear envelope start to form
129
What happen in cytokinesis
With the formation of the cleavage furrow, the pinching action seperates cytoplasm into two seperate cells and deepens, pinching the cell membrane inwards , sperating into two deaughtwr cells
130
How different type of cell and function varies in need of cell cyle
1. Cell that never divide,, specialized , stuck at gap 0
2. Normally do not,, till induced to do so like skin cells
3. Normally do,, tissue stem cells
131
How different type of cell and function varies in need of cell cyle
1. Cell that never divide,, specialized , stuck at gap 0
2. Normally do not,, till induced to do so like skin cells
3. Normally do,, tissue stem cells
132
What happen in cell cyle control system
G1 checkpoint: dpes the cell need to reproduce agn
G2 cehcpoint: is dna damaged in s phas
M checkpoint: are chromosome attached to spindle
133
How uncontrolled cell division affect cell cycle control and defects (term: actively promoting, inhibiting)
Genes actively promoting cell divison (proto oncogens) are not turm of the right time, it become oncogens and lead to cancer
Gene inhibit cell divison (tumor supressor gene) stop working will lead to cancer
134
What are the 3 ways proto oncogens become oncogenz
1. Translocation
2. Gene amplication
3. Point mutation
135
What happen in translocation to become oncogens
When segement of one chromosome breaks off and attaches to another chromosome,, this leads to activation of oncogens if the translocated segement containes a proto oncogens and under the control of highly active promoter region
136
What happen in gene amplication to cause oncogens
Duplication of specific region of dna within a chromosome, resulting in increase of no of copies of a particular gene, which to activation of oncogens by causing their overexpression of gene
137
What happen in point mutation to cause oncogens
1. Within a control element
- Control elements, such as promoters, enhancers, and silencers, are regions of DNA that regulate the expression of genes by controlling the initiation of transcription or the rate of transcription.
- A point mutation within a control element can affect the binding of transcription factors or other regulatory proteins to that element. This can alter the efficiency or specificity of transcriptional regulation.
- For example, a point mutation within a promoter region might create or disrupt a binding site for a transcription factor, leading to either increased or decreased expression of the associated gene.
2. Within a gene
- affect the sequence of amino acids, altering protein structure n function
- missense mutation, nonsense mutation, or a frameshit mutation,, leading to a completely different amino acid sequence
- this can cause proein that are completely active thus uncontrolled reactions or mutated protein that are degradation resistant (inhibit) causing oncogens to be activated
138
What are the central digma of biology
Dna (contain information) transcripted to rna (written in nucleotides) translated to proteins (genetic info)
139
What dna stand for
Deoxyribonucleic acid
140
What rna stand for
Ribonucleic acid
141
What are 3 main groups in nucleic acid structure
Backbone: Phosphate sugar
Determine info coded: nitrogenois base
142
What is the base pairing rule
C = G
A= T / U
143
What are the nitrogwnous bases
Adenine thymine
Guanine
Cytosine
Urcail only in rna
144
Why gc bond are stronher than at
AT has 2 hydrogen bond
CG has 3 hydrogen bond
145
Diff between dna and rna structure
Dna has 5 c and 1 oh group
Rna has 5 c and 2 oh group
146
What is the bond between nucleic acids called
Phosphodiester bond
147
What carbon in sugar does the phosphate group connects to
3 and 5 of sugar of adjacent nucleotides
148
What is the structure strand of dna
Double helix
149
What is the structure strand of dna
Double helix
150
What is the point where replication begins called
Origin of replication
151
How origin of replication are decided
By the initiator protein where these sequences have exhibit specific structural features
152
Why is impt for origin or replication to occur at the same place frequently
Accurate transmission of genetic information from one generation to another
153
Why dna strand is seperated
To allow enzyme or polymearse to come through
154
How dna strand is seperated
Helicase
155
Is it endo or exo overall process in repkucating new strand on the template strand
Endo as they need net input energy to procees
156
Diff between purine and pyrimides
Purine is adenine and guanine
Pyrimides is cytonse uracil and thymine
157
What is the difference between incorparated and not been nucleotide into dna
B4 incorporation, nucleotides has 3 phosphate group
Aft incorporation, each nucleotide has one phospahte grp attached
158
Importance of molecular comtrol of the cell cycle
To ensure accurate replication and division of cells
159
Key components for molecular control of the cell cycle
1. Cyclin
2. Cyclin dependent kinase
3. Maturarion promoting factor
160
Process in molecular control of cell cyle
1. Cyclin production start in s phase
2. Accumulates until g2 phase
3. Bond with cdk to form mpf
4. Mpf actiavtes proteins that drive mitotic events,,, passes g2 event
5. Mpf is degraded, and cylin is recycled
161
What happen if there is failure in the cell cyle
Cyclin, cdk will be inhibited by the cell cycle checkpoints
162
Why is it importnat cdk is not active unles bounded
Allow cell to conserve energy
163
Differenent levels of cyclin, cdk, mpf throught the whole cell cyle
Cyclin : Increasing till every m phase
Cdk : constant
Mpf : highest only at m phase
164
What happen in gap 0 phase
Have not pass gap 1
Are non dividing cells
Represent the majority of cells in your body
165
What is the direction of transcription and what durection does rna is being made
Driection of transcriptiom: 5 to 3
3 to 5
166
Why is there a need for pre mRNA in eukaryotes
To go through rna splicing to remove non coding sequences
167
Introns vs exons
Introns are the non coding bits
Exons are the coding bits
168
What is alternative splicing
More than one mRNA can be made from the same gene (chain of dna) but with differen proteins included
169
What is polymerase ii
Its is an enzyme used to transcript mRNA
170
How many nucleotides are in one codon/amino acid
3
171
What is gene
Its a basic unit of inheritance with instruction for a trait
172
What is trait
A heritable physical and physiological characteristic
173
What is genotype
Its contains the genetic information,, contains 2 alleles
174
What is phenotype
Set of observable physical traits
175
Relation of alleles to locus
Two alleles of one genetic information (eg color of flower) is in the same locus (position) on homologous chromosome
176
Allele in Homozygous vs heterozygous
Homo: identical
Hetero: different
177
How gene related to the observable traits
Gene code for gene that are responsible for the characteristic of trait
178
Molecular anatomy of a gene
Coding and control (promtoer) region
179
How dna is compacted
Wrapping dna around a protein called hostoned --> chromatin --> further compacted to chromosome
180
What are the type of histones
H1 h2a h2b h3 h4
181
Characteristic of hostones and why
They are basic and positivelu charged to associate with the negatively charged dna
182
Type of chromatin
Euchromatin, relaxed,,, genes likely to be found here
Heterochromatin, compact
183
Type of chromatin
Euchromatin, relaxed,,, genes likely to be found here
Heterochromatin, compact
184
How many chromosomes are there in human genome
22 autosomal chromosome
2 unpaired sex chromosome, X and Y
185
What is virus
There are oligatory ( rely on host mechanism) and intreacellular (infect host cells to reproduce), whose genetic material is surrounded by protein capsid
186
What are the stage of virus life cycle
1. Attachement
- to the surface by inceration with cell receptors
2. Penetration
- virus goes into tbe cytoplasm through endocytosis
3. Uncoating
- viral capsid is removed, releasing nucleic acid
4. Transcription or translation
- mRNA are produced to make more protwins
5. Genome replication
- more copies of virus genome to make more virus particles
6. Assembly
- amssembly of protein capsid
7. Release
- by cell lysis (membrane breaks dowm) or budding (exocytosis)
187
What are the means of viral replication
1. Lytic cyle
- host cell will die
2. Lysogenic cycle
- incorporating the viral genome to host cell genome
188
What are the replication mechanism in virus (contradicting the central dogma)
1. Rna dependent rna polymerase
- dna to positive rna to protein
- some positive rna is converted to negatuve rna to make more rna
2. Reverse transcriptase (in retroviruses)
- dna to rna to protein
- rna is used to make dna
189
Difference between positve rna and negv rna
Positive can be immediately transltaed
Negat cannot but good for evading host immune response as they are not directly infectious
190
Where does gene expression occur in bacteria
Since there are no nucleus,, transcription and translation occue in the same place in the cytoplasm
191
How bacteria respond to environmental change
By regulating their gene expression
192
What structure of a typical operon
1. Promoter region
- promoter,,, rna polymerase sequenced the specific dna sequence for it to bind and initiate transcriptiom
- operator,,, turn gene on or off, intefering with rna polyemerase activity
2. Coding region
- multiple gene
193
Repressible vs induced operon
194
What happen in repressible operon process
195
Trp operon vs lac operon
Trp operon : prokaryotes, bact
Lac operon : eukaryotes
196
7 steps in gene regulation in eukaryotes
1. Chromatin remodeling
2. Transcriptional control
3. Rna processing
4. Rna localisation
5. Rna stability and degradation
6. Translational control
7. Protein folding
197
Why need enhancers in gwne regualrion
Enhancers increase the transcription of gene located at a distance from them on the same chromosome
They allow increase or decrease rate of transcription
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What is homeotic mutation
One body part in switch with another body part
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Pre vs post transcriptional control
Pre:
1. Chromatin remodelling
2. Histones
3. Transcription factor binding
Post:
1. Splicing and cappinh
2.
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What happen in translational gene regualtion
Controls the rate of protwin synthesis
Control the ribosome bind to mRNA,, ^^^^
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Steps in polymerase chain reaction
1. Denaturation
2. annealing, attach dna primers
3. Extension , dna polymerase (taq polymerase)
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Cohesive (blunt) vs sticky ends
Blunt has no overhangs thus lower efficiency of ligation
Sticky ends are often preferred for dna cloning and recombinat due tot the their ability to facitility specific and directional ligation of dna fragemnrs
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Factors affecting rate of dna migration through agrose gel
Molecular size and shape of the
dna as larger molecules move slowly due to gretaer drah
Agarose concentration as more conc, the fragment move slower
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How dna move through agrpse gel
As dna negatuvely charged move towards positively charge
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What is the term called for the use of size markers for dna length
Dna ladder
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How many chromosomes are in gametes and somatic cells in hunan
Gametes have 23 chromosomes (n)
Somatic have 46 chromoseome (2n)
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Sexual reproduction of euakryotes through wat process
Meiosus to generate haploid cells (gametes) to produce diplois zygote
Zygote then go through mitosis to become multicellular organism
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What is meiosis
It produces haploid gamete, sperm or egg cells
It goes through s phase for dna replicatio then goes thru 2 cell divisions which are for:
1. Reduxtion in division
2. Seperation of chromatids
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What happen in first divison of meiosis
Seperating homologous chromosome
n = 23
210
What happen in second division of meiosis
Seperate the sister chromatids
Result in 4 haploid cells
n = 23
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Does meiosis go through interphase
Yes
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How does meiosis increase genetic variation
By segregation and independenr assortment, homologous assortment contain same gene but diff allele variant at each locus
Through interphase in metaphase,, there can be crossover/recombination (exchnge of genetic information)
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Crossing over increases new combinations of alleles on a chromosome. True or false
True
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Genetic variation results from:
- mutation,,, causing new allele
- independent assortment of homologous chromosome pairs,,, different combinations of parental combinations in diff gametes
- recombination (crossing over),,, new combinations pf allelels on chromosomes
- fusion of gametes
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What if meiosis goes wrong
- non disjuction in meiosis 1 or meisois 2
N + 1 / N - 1
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Impact of error in mitosis vs meiosis
In mitosis, errors primarily affect somatic (body) cells, which undergo division for growth, repair, and maintenance of tissues. Errors in mitosis can lead to chromosomal abnormalities, genetic mutations, cell death, tumor formation, and developmental abnormalities in the affected tissue or organ.
In contrast, meiosis specifically produces gametes (sperm and egg cells) for sexual reproduction. Errors in meiosis can result in gametes with chromosomal abnormalities, such as aneuploidy (abnormal chromosome number), which can lead to developmental disorders, birth defects, or conditions like Down syndrome in offspring. Additionally, errors in meiosis can impact fertility by affecting the production of functional gametes.
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Mutations can be induced or spontaneous. Tru or false
Tru
218
Loss of function mutation definition
Deletion of gene sequence
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Gain of function mutation
Amplify the expression of genes
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How dna is transferred between bacteria
1. Confugation,,,, direct cell to cell contact
2. Transformation,,,, taken up plasmid
3. Transductiom,,,, by bacterial virus
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Hydrogen bonds from dna allows easilt to be broken and reform with changes in temeprature in pcr. Tru or false
Tri
222
Mono vs di hybrid cross
Mono: cross between two individuals that differ in one trait governed by one gene with two different alleles
Di: cross between two individuals taht differ in 2 traits governed by 2 different genes, each gene having 2 different allele
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Diff between segregation and indpendent assortment
Segregation occur in meiosis ii seperating the allele of a single gene
Independent assortment occur in mesiosis i seperating the chromosome to either the maternal or paternal
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What is co dominance
Both shows without blending
225
What is epistatis
The expression of gene mask or modify another expression of gene
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What is pleiotropy
Songle gene has multiple traits
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What us polyploidy and aneuploid
Poly: too little or many sets of chrpmosomes
Aneu: too little or many number of chromosome
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What id assymetric inheritance and species epecific slection
Assymetirc: differentiating cell
Species specific: external or env factors affcet the selection
229
Key aspects of natural selection
Acts on population
Only affect heritable traits
Varies by environmental context
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4 alteration on chromosome steucture
1. Deletion
2. Insertion
3. Inversion (reverse a segment)
4. Translocation (move segement from one chromosome to another)
231
What are 2 ways that cause mutation in mRNA (not multiple of 3)
Point mutation and insertion and deleteion mutation
232
What happen in point mutation
1. Silent,,, no effect, amino acid is the same
2. Missense,,, read wrongly, different amino acid
3. Nonsense,,,, premature termination
233
What happen in in insertion deleteion mutatiom
1. Extra,,, 1 nucleotide pair added, cause nonsense
2. Missense,,, 1 nucleotide pair removal, cause misense
3. 3 nucleotide pair deletion,,, no framshift but removal of one amino acid
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Reduction in fitness is when there is decrease in amino acid (protein). True or fale
Tru
235
Mutation is disadvantageous. Tru or false
Tru
236
Whcih will cause greater impact loss of one bp or one amino acid
One bp,,,, it result in fram shift mutation which will impact alll of the following codon and amino acid
237
Evolution = natural selection + mutation + genetic drift + gene flow
Yes
238
What is genetic drift
Removal of alleles from a population over time due to chance,,, chnagibg the allele frequenxy,,,
Smaller population will face a greater genetic drift
239
What happen in mutatiom
Addition of new allele in a population,,, large population has higher mutation rate due to more chances
240
What is gene flow
1. Immigration
2. Emmigration
Btwn the 2 population,, allele will stay similar
241
Immigration add allele
242
Mode of selection between frequenxy of indivuduals and phenotypes
1. Directional selection
- favour one extreme end of the phenotype
2. Disruptive
- favor two extreme nd of rhe phenotype and not the middle
3. Stabalising sleection
- favor only the middle phenotype
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What is qtl
Quantititave trait locus
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What is qtl used for
To identify region of the genom that are associated with variation un quantittaive traits
245
What is snp
Single nucleotide polymorphism
Its is a type of genetic variation that occurs when a single nucleotide base at a specific position in the genome differs between indivisuals within a populatikn
246
Coupling vs repulsion linkage
Cis same side
247
What is lateral gene transfer
It is the transfer of genetic material between diff organisms, often unrelated species through mechanisms other than vertical inheritance
248
What is nondisjunction
A pair of homologous chromosome failed to segregate at anaphase so that both chromosome of the pair pass to the same daughter cell
249
Anything over 50 map units are unlinked. Tru or fals
True
250
Tumor suppressor gene vs proto oncogens
Tumor suppressor inhibit cell growth and promote cell death
Proto oncogens support cell growth and division
251
Tumor suppressor gene vs proto oncogens
Tumor suppressor inhibit cell growth and promote cell death
Proto oncogens support cell growth and division
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What is polymerase
Polymerase is an enzyme responsible for synthesizing long chains of polymers or nucleic acids, such as DNA or RNA, by catalyzing the bonding of nucleotides together. It plays a crucial role in processes like DNA replication and RNA transcription.
253
Hardy weinbery principle
No mutation, natural selection, genetic drift, or gene flow
