Module 3 Flashcards
1
Q
What is genetics?
A
The study of gene function, genetic diseases, inheritance, evolution, and population genetics.
2
Q
Where is DNA located in a eukaryotic cell?
A
Within the nucleus of the cell, arranged as chromosomes.
3
Q
What do chromosomes contain?
A
Genes which encode proteins.
4
Q
What role do some proteins, encoded by genes, play in cellular metabolism?
A
They act as enzymes.
5
Q
What is an example of a metabolic pathway?
A
The conversion of the amino acid phenylalanine into melanins.
6
Q
What is the Central Dogma of molecular biology?
A
The process that describes the flow of genetic information from DNA to RNA to protein.
7
Q
What is the first step of the Central Dogma?
A
Transcription.
8
Q
What happens during transcription?
A
Enzymes transcribe information for a particular gene from DNA into RNA.
9
Q
What is the second step of the Central Dogma?
A
Translation.
10
Q
What is the language of DNA and RNA written in?
A
Nucleotide bases (A, G, C, T).
11
Q
What is DNA short for?
A
Deoxyribonucleic Acid.
12
Q
What is the structure of DNA?
A
A double stranded alpha DNA molecule.
13
Q
What is complementary base pairing in DNA?
A
The way the alpha helical strand is formed through non-covalent base pair binding.
14
Q
Which bases pair together in DNA?
A
G with C and A with T.
15
Q
What are the components of a nucleotide?
A
- A 5C sugar (deoxyribose)
- A phosphate group
- A base (A, T, C or G)
16
Q
What differs between DNA and RNA regarding sugar?
A
DNA contains deoxyribose, while RNA contains ribose.
17
Q
What is the base composition of RNA?
A
C, G, A, U.
18
Q
What type of bases are purine bases?
A
Bases with 2 rings: Adenine and Guanine.
19
Q
What type of bases are pyrimidine bases?
A
Bases with 1 ring: Cytosine, Thymine, Uracil.
20
Q
What connects the nucleotides in a single strand of DNA?
A
Covalent bonds between the sugars and phosphates.
21
Q
What is the directionality of DNA strands?
A
Each strand has a 5’ end and a 3’ end.
22
Q
What charge do phosphate groups have?
A
A negative charge.
23
Q
How are the two chains of nucleotides in DNA held together?
A
By hydrogen bonds between the bases.
24
Q
What is the hydrogen bond composition between bases in DNA?
A
- T - A has 2 hydrogen bonds
- C - G has 3 hydrogen bonds.
25
What is stoichiometry in the context of DNA?
The quantitative relationship between constituents in a chemical substance.
26
List the rules of base stoichiometry in DNA.
* The number of A's equals the number of T's
* The number of G's equals the number of C's
* The number of purines equals the number of pyrimidines.
27
What is the orientation of the two DNA strands?
The two sugar-phosphate backbones are anti-parallel.
28
What are the two strands of double-stranded DNA differentiated as?
* Sense (leading) strand
* Antisense (lagging/template) strand.
29
What does the DNA sense strand resemble?
It looks like the messenger RNA (mRNA).
30
What is the role of the DNA antisense strand?
It serves as a template for mRNA.
31
What is the relationship between mRNA and the DNA antisense strand?
The mRNA is complementary to the DNA antisense strand.
32
What happens during translation?
the mRNA is translated from a nucleotide alphabet to an amino acid alphabet
33
Where is DNA located in eukaryotic cells?
In chromosomes in the nucleus
## Footnote
Eukaryotic cells contain a nucleus where chromosomes are found.
34
What does each chromosome contain?
One very long molecule of double stranded DNA
## Footnote
Each chromosome consists of two strands of DNA.
35
How is the DNA molecule structured in an intact chromosome?
Packed into a much more compact structure
## Footnote
This packing is essential for the organization and function of DNA.
36
What happens to chromosomes during mitosis?
They become very condensed
## Footnote
This condensation is crucial for proper segregation of chromosomes.
37
What is the size range of genes?
From 500 to 2 million nucleotide base pairs
## Footnote
Gene size can vary significantly across different organisms.
38
How many genes do bacteria typically have?
~1,000 genes
## Footnote
Bacterial genomes are generally smaller and less complex than eukaryotic genomes.
39
How many genes do humans typically have?
~30,000 genes
## Footnote
This number reflects the complexity of human genetics.
40
What is genome size?
The complete set of genetic information
## Footnote
Genome size varies widely among different organisms.
41
What is an example of genome size in humans?
Up to 1 million bases
## Footnote
This refers to the total number of nucleotide base pairs in the human genome.
42
43
44
What are the two main steps of protein synthesis?
Transcription and Translation
45
What does transcription involve?
Making a copy of the genetic information (synthesis of mRNA from DNA template)
46
What is translation in the context of protein synthesis?
Decoding the genetic information to determine the sequence of amino acids within a protein
47
What is the flow of inherited information in a cell?
DNA to RNA to Protein
48
In prokaryotic cells, where does mRNA transcription and translation occur?
In the cytoplasm
49
Do prokaryotic cells have a nucleus?
No
50
Where does transcription occur in eukaryotic cells?
In the nucleus
51
What is pre-mRNA?
The original RNA transcript before it is processed into mature RNA
52
What must happen to pre-mRNA before it leaves the nucleus?
It must be processed into mature RNA
53
Where does mRNA translation and protein synthesis occur in eukaryotic cells?
In the cytoplasm
54
What binds to the ribosomes during translation in eukaryotic cells?
mRNA
55
Fill in the blank: Transcription occurs in the _______ of eukaryotic cells.
nucleus
56
Fill in the blank: Translation occurs in the _______ of eukaryotic cells.
cytoplasm
57
True or False: In prokaryotic cells, transcription and translation are separated by the nucleus.
False
58
What is RNA polymerase (RNAP)?
An enzyme that builds RNA chains using DNA as a template.
59
Where does transcription begin and end?
Begins at the promoter of a gene and ends at the terminator.
60
What is the function of the promoter?
Control region that allows certain genes to be switched on/off at certain times.
61
What does the transcription start site indicate?
Tells RNAP where to start transcription.
62
What is the coding region?
The code for the amino acids that will be copied.
63
What is the role of the terminator in transcription?
Tells RNAP where to stop.
64
What occurs during the initiation stage of DNA transcription?
RNAP binds to the promoter of the gene.
65
What are transcription factors?
Proteins that regulate the process of transcribing DNA into RNA.
66
In which region do transcription factors bind?
Regulatory DNA sequences in the promoter region of genes.
67
What happens during the elongation stage of transcription?
RNAP moves downstream and builds the RNA transcript 5' to 3'.
68
What is a transcription bubble?
An area where RNAP opens up the DNA at that region.
69
How does RNAP add nucleotides during elongation?
According to the sequence of nucleotides in the non-coding strand.
70
What is the relationship between the non-coding and coding strands during transcription?
The RNA transcript is the same as the coding strand.
71
What is the base pairing rule for RNA?
A in DNA pairs with U in RNA (not T).
72
What occurs at termination during transcription?
The new RNA transcript is released & RNAP detaches from the DNA template strand.
73
What is an exon?
A segment of DNA or RNA containing information coding for a protein or peptide sequence.
74
Do exons occur in prokaryotic cells?
No, only in eukaryotic cells.
75
What is an intron?
A segment of DNA or RNA that does not code for proteins and interrupts the sequence of genes.
76
Do introns occur in prokaryotic cells?
No, only in eukaryotic cells.
77
What is an untranslated region (UTR)?
Sections on either side of a coding sequence on a strand of mRNA.
78
What is the 5' UTR?
The untranslated region found on the 5' side of a coding sequence.
79
What is the 3' UTR?
The untranslated region found on the 3' side of a coding sequence.
80
What happens to introns after RNA is transcribed?
They are removed (spliced out) so only exons remain for translation.
81
What is the end result of the transcription process?
mRNA is produced.
82
What is the sense DNA strand?
The strand from which we derive the written gene sequence
## Footnote
This is the strand that we read with our eyes when studying DNA sequences.
83
What strand does RNA Polymerase use as a template for RNA transcription?
The antisense DNA strand
## Footnote
This strand is also referred to as the template strand.
84
Define a codon.
3 consecutive nucleotide bases that represent an amino acid 'word'
## Footnote
Codons are used to communicate a gene by forming 'words' and 'sentences' with the nucleotide alphabet.
85
What is the start codon?
The 1st codon of a mRNA transcript translated by a ribosome
## Footnote
It always codes for methionine in eukaryotes and a modified methionine (fMet) in prokaryotes.
86
What is a stop codon?
A nucleotide triplet within mRNA that signals termination of translation
## Footnote
Also known as a termination codon.
87
What is the function of Transfer RNA (tRNA)?
Transport amino acids from the cytoplasm to a ribosome
## Footnote
It connects the nucleotide alphabet through the anti-codon to the amino acid alphabet.
88
What are the two important regions of tRNA?
* The amino acid attachment site
* The anti-codon
## Footnote
The anti-codon is a sequence of three adjacent nucleotides forming a unit of genetic code in tRNA, corresponding to a complementary codon in mRNA.
89
What does complementary base pairing refer to in translation?
The pairing of the amino acid-tRNA anti-codon to the codon in mRNA
## Footnote
This process facilitates the translation of genetic sequence into amino acid sequence.
90
Where does translation take place?
In the ribosome
## Footnote
The ribosome is the cellular machinery responsible for synthesizing proteins.
91
What is the role of the P site in the large ribosomal subunit?
Binds to the tRNA holding the growing polypeptide chain of amino acids
## Footnote
Also known as the peptidyl site, it connects the previous amino acid with the next one in the A site.
92
What is the function of the A site in the large ribosomal subunit?
Binds to the aminoacyl tRNA holding the new amino acid to be added to the polypeptide chain
## Footnote
This site is also referred to as the acceptor site.
93
What happens at the E site in the large ribosomal subunit?
Serves as a threshold before a tRNA leaves the ribosome
## Footnote
Known as the exit site, it is where tRNA without its amino acids exits.
94
What does the small ribosomal subunit bind to?
The mRNA molecule
## Footnote
This binding is essential for the translation process to begin.
95
At what codon does translation begin?
At the first AUG codon (start codon) at the 5' end of the mRNA
## Footnote
AUG codes for the amino acid methionine (met).
96
What is the anti-codon for the start codon AUG?
UAC
## Footnote
This anti-codon is present on the tRNA that carries methionine.
97
What is required for the amino acid in the P site to connect to the amino acid in the A site?
The presence of GTP
## Footnote
GTP hydrolysis provides the energy needed for this connection.
98
Is the process of translation energy-dependent?
True
## Footnote
GTP hydrolysis is necessary for the translation process.
99
What is the first step in the process of translation?
tRNA entry into the A site of the ribosome
## Footnote
This step initiates the addition of new amino acids to the growing polypeptide chain.
100
What occurs after peptide bond formation in translation?
Release of the tRNA in the P site of the ribosome
## Footnote
This step allows the ribosome to prepare for the next cycle of translation.
101
What is the final step in the process of translation?
Ribosome movement one triplet forward
## Footnote
This movement allows the ribosome to read the next codon on the mRNA.
102
What is a mutation?
Any change in DNA sequence
## Footnote
Mutations can affect gene function and protein synthesis.
103
What causes mutations?
Mistakes during DNA replication and damage from:
* Some chemicals
* Ultra-violet light
* Radiation (X-rays)
## Footnote
These factors can lead to structural changes in DNA.
104
What can mutations in the coding region of a gene change?
The amino acid sequence of a protein
## Footnote
Such changes can affect protein function and organism traits.
105
What is a point mutation?
A type of mutation that causes a single nucleotide base change, insertion, or deletion of DNA or RNA
## Footnote
Point mutations can lead to significant biological effects.
106
What is an example of a consequence of the sickle-cell mutation?
People with 2 copies of the sickled-cell mutation have anaemia
## Footnote
One copy provides resistance to malaria.
107
How are all proteins synthesized in eukaryotic cells?
By ribosomes
## Footnote
Ribosomes can be free in the cytosol or attached to the rough endoplasmic reticulum.
108
Where are cytosolic ribosomes located?
In the cytosol
## Footnote
They synthesize proteins for the nucleus, cytosol, mitochondria, and chloroplasts.
109
What do rough ER ribosomes synthesize?
Proteins located in the ER, Golgi apparatus, lysosomes, plasma membrane, or secreted proteins
## Footnote
These proteins are part of the secretary pathway.
110
What is the first step in the synthesis of a secreted protein?
mRNA moves from the nucleus to a ribosome on the surface of the rough ER
## Footnote
This initiates the translation process.
111
What happens to the amino acid chain during translation on the rough ER?
The chain is pushed into the cisternal space of the rER
## Footnote
This is where the protein folding and modification begin.
112
What is added to proteins in the rER?
Sometimes carbohydrates
## Footnote
This process is part of post-translational modification.
113
What occurs after proteins are completed in the rER?
They collect in the transitional ER which pinches off a vesicle
## Footnote
This vesicle can transport proteins to the Golgi apparatus.
114
What is the role of the Golgi apparatus?
A warehouse for receiving, sorting, and shipping proteins
## Footnote
It is crucial for post-translational modifications.
115
What is post-translational modification (PTM)?
The covalent modification of proteins with other molecules such as sugars and lipids after protein synthesis
## Footnote
PTM can affect protein function and localization.
116
What do cells that secrete proteins have in terms of Golgi apparatus?
An extensive Golgi apparatus network
## Footnote
Example: insulin-secreting cells in the pancreas.
117
What is the cis face of the Golgi apparatus?
The membrane side located towards the ER that receives vesicles from the ER
## Footnote
It is involved in the initial processing of proteins.
118
What does the trans face of the Golgi apparatus do?
Produces vesicles that pinch off and are transported to other destinations
## Footnote
This face is essential for distributing proteins to their final locations.
119
What is a mutant?
A gene which has a change in function due to a change in a DNA sequence (a mutation)
## Footnote
Mutants can be either non-functional or have a different function.
120
What are mutants used for in genetic research?
To identify genes that play a role in a particular biological process
## Footnote
Examples include biochemical pathways, cell division, tumourogenesis, flowering, and development.
121
What can mutagenic experiments define?
The functions of genes
## Footnote
These experiments are often performed on model organisms.
122
What is mutagenesis?
Induction of mutations
## Footnote
Methods include x-rays, chemical mutagens (e.g., smoking), and ultraviolet light.
123
What are some methods of inducing mutations?
Mutagenesis methods include:
* X-rays
* Chemical mutagens
* Ultra-violet light
## Footnote
Smoking is an example of a chemical mutagen.
124
What types of genetic research can be conducted through the study of naturally occurring genetic defects?
Human genetic diseases
## Footnote
These studies help understand the genetic basis of diseases.
125
What are normal variants in genetic research?
Variants that confer traits like disease resistance in plants
## Footnote
They represent the natural genetic diversity within a species.
126
List the characteristics of a model organism for genetic research.
Characteristics include:
* Short life cycle
* Large numbers of offspring
* Easy to handle and propagate
* Easy method to introduce DNA
* Small genome
## Footnote
These characteristics facilitate genetic studies.
127
What are examples of prokaryotic cells used as model organisms?
Escherichia coli (E. coli k12)
## Footnote
Prokaryotes are often simpler and easier to manipulate genetically.
128
Name a common eukaryotic model organism.
Saccharomyces cerevisiae (yeast)
## Footnote
Yeast is frequently used in molecular genetics due to its eukaryotic nature.
129
Name three eukaryotic animals used as model organisms.
Examples include:
* Vinegar fly
* Nematode
* Mouse
## Footnote
These organisms are widely used in genetic and developmental biology.
130
What are examples of eukaryotic plants used as model organisms?
Maize and Arabidopsis thaliana
## Footnote
These plants are used to study genetics, development, and plant biology.
131
How can information from model organisms be applied?
To other non-model organisms like humans, agricultural plants and animals, and disease-causing microbes
## Footnote
This transfer of knowledge helps in various fields, including medicine and agriculture.
132
Fill in the blank: The double-muscling trait is associated with the _______.
myostatin gene
## Footnote
This example illustrates the application of genetic research in understanding traits.
133
What is the role of the Office of the Gene Technology Regulator (OGTR) in Australia?
Oversees the development and environmental release of GM organisms under the Gene Technology Act 2000
134
What must all genetically modified (GM) foods intended for sale in Australia and New Zealand undergo?
A safety evaluation by Food Standards Australia New Zealand (FSANZ)
135
True or False: FSANZ will approve a GM food unless it is safe to eat.
False
136
What is not considered genetic modification when adding an enzyme to food?
It is modified by a recombinant enzyme
137
What is the chemical nature of DNA from different organisms?
Chemically identical
138
What determines the properties of organisms?
Genes
139
What can be achieved through genetic engineering?
Cut pieces of DNA and join different pieces to create new combinations of genes
140
What is a key application of recombinant protein production?
Use bacteria to produce human growth hormone for medical purposes
141
What is the purpose of the human growth hormone (GH) gene?
Codes for GH required for normal growth
142
What is one of the dangers of producing GH from human tissues?
Infectious agents present in human tissues (prions)
143
What is the first step in the genetic engineering process?
Isolate DNA from bacteria, humans
144
What is the function of restriction enzymes?
Cut DNA molecules at precise points to isolate genes
145
What type of ends can restriction enzymes leave after cutting DNA?
* 5' sticky ends * 3' sticky ends * Blunt ends
146
What is EcoRI and where is it derived from?
A restriction enzyme from E. coli
147
What specific DNA sequence does the EcoRI restriction enzyme cut?
GAATTC
148
What is the role of DNA ligase?
Joins DNA molecules
149
True or False: DNA ligase can join incompatible ends.
False
150
What must be avoided when creating recombinant DNA molecules?
Disrupting genes from the bacterial cell
151
What are bacterial plasmids?
Small, circular DNA molecules found in bacteria, separate from the bacterial chromosome
152
What is the first step in inserting a growth hormone gene into a plasmid?
Cut plasmid DNA with restriction enzyme (e.g., EcoRI)
153
What is transformation in the context of genetic engineering?
Putting plasmid DNA into bacterial cells
154
What is the first step in the transformation process?
Incubate bacteria with plasmid
155
What is the final step in recombinant protein purification?
Use to treat growth deficiency
156
Fill in the blank: Recombinant DNA molecules must be put back into _______ for gene expression.
cells (i.e., bacterial cells)
157
Who developed the techniques for DNA fingerprinting and DNA profiling?
Prof Sir Alec Jeffreys
## Footnote
British geneticist known for his pioneering work in DNA profiling.
158
What is DNA profiling used for?
Parentage testing and criminal investigation
## Footnote
It helps distinguish individuals based on their unique DNA sequences.
159
What percentage of human DNA sequences are the same in every person?
99.9%
## Footnote
Despite this similarity, enough differences exist to identify individuals.
160
What are Variable Tandem Repeats?
Repeated sequences found in DNA
## Footnote
They vary in number at each locus between individuals.
161
What is the significance of cutting DNA with restriction enzymes in DNA fingerprinting?
It allows for the analysis of fragments with varying repeat numbers
## Footnote
This helps distinguish between individuals based on DNA fragment size.
162
What is the first step in the DNA fingerprinting methodology?
Extract DNA
## Footnote
This can be done using samples from blood, skin cells, or hair follicles.
163
What process separates DNA fragments in gel electrophoresis?
Electrophoresis
## Footnote
DNA moves towards the positive electrode due to its negatively charged phosphate backbone.
164
What happens to smaller DNA fragments during gel electrophoresis?
They move fastest
## Footnote
Smaller fragments can slip through the gel more easily.
165
What biological materials can DNA be extracted from for forensic science?
Blood, skin, hair, semen
## Footnote
These samples can be used to match DNA fingerprints in investigations.
166
What is the purpose of paternity testing using DNA fingerprints?
To identify inherited bands from mother or father
## Footnote
This helps determine biological parentage.
167
How do parentage tests work in agriculture?
By exclusion
## Footnote
Tests can exclude a sire or dam as a possible parent but cannot confirm parentage with 100% accuracy.
168
What is a standard set of markers used in cattle DNA fingerprinting?
12 DNA markers tested in 3 separate marker groups
## Footnote
This is a common approach for parentage testing in cattle.
169
What is the aim of identifying sires and dams with specific alleles in production traits?
To associate them with high-value production traits
## Footnote
Examples include fine wool, muscling, and milk production.
170
What are viruses in terms of cellular structure?
Not cellular (i.e. acellular) and completely different from living cells
## Footnote
They cannot metabolise or independently self-replicate.
171
Can viruses metabolize or self-replicate independently?
No, they cannot metabolise and cannot independently self-replicate
## Footnote
Viruses can only replicate within a living cell.
172
What is the composition of a virus?
Nucleic acids, proteins, and sometimes a stolen lipid membrane envelope
## Footnote
Viruses do not have their own membrane.
173
How many genes do viruses typically have?
Composed of 10s to 100s of genes
174
What protects the genetic material in a virus?
Protein coat (capsid)
## Footnote
The capsid protects the nucleic acid material inside.
175
How can viruses be visualized?
Need an electron microscope to see them
176
What are the components of virus particles?
Genetic material (DNA or RNA), protein coat (capsid), and sometimes an envelope
## Footnote
The envelope is lipid and protein, obtained from the host cell.
177
What features of living organisms do viruses exhibit?
Carry genetic material, reproduce (requires a host cell), evolve, and are subject to natural selection
178
Are viruses considered alive outside of host cells?
No, they are NOT alive outside of eukaryotic/prokaryotic cells
## Footnote
They cannot metabolise or reproduce independently.
179
What technological advances contributed to the discovery of viruses?
The story of virus discovery parallels technological advances such as the electron microscope and TMV
## Footnote
TMV = Tobacco mosaic virus.
180
What is the significance of the electron microscope in studying viruses?
Had a small wavelength, which is much smaller than light, allowing for high resolution
181
What does TMV stand for?
Tobacco mosaic virus
182
How do viruses utilize the host cell during infection?
The virus uses the host infected cell's genetic machinery, especially the ribosomes
183
What are the main components used to classify viruses?
Viruses are classified by their:
* Genetic material (DNA or RNA)
* Protein coat (capsid shape)
* Envelope (lipid & protein, obtained from host cell)
## Footnote
Sometimes they steal an envelope from the host; sometimes they don’t have one.
184
What are the different types of viral genetic material?
Virus particles (virions) are classified based on their genome structure:
* dsDNA viruses
* ssDNA viruses
* dsRNA viruses
* (+)ssRNA viruses
* (-)ssRNA viruses
* ssRNA-reverse transcriptase (RT) viruses
* dsDNA-RT viruses
## Footnote
(ds = double stranded, ss = single stranded, + = leading strand, - = template strand, RT = reverse transcriptase)
185
What shapes can viral capsids take?
Most viruses are:
* Rod-shaped (actually helical)
* Icosahedral (20 triangular sides)
* A combination of these
## Footnote
RNA is protected inside the capsid.
186
How are viral capsid proteins formed?
The proteins that compose the viral capsid:
* Are transcribed and translated using infected host's cellular machinery
* Are self-assembled
## Footnote
This makes virus construction an efficient process.
187
What is a viral envelope?
A viral envelope is a lipid envelope derived from the host cell plasma membrane that many animal viruses have.
## Footnote
It wraps around the virus particle as it leaves the host cell, often leading to the cell's destruction.
188
What unique structures do some bacterial viruses have?
Some bacterial viruses (e.g., phages) have complex attachment and injection structures to facilitate entry into prokaryotic cells.
## Footnote
These include spike proteins that latch onto receptors in bacterial cells.
189
What is the general mechanism of viral infection and transmission?
1. The virus uses capsid proteins to bind to host cell receptors.
2. Enters the cell.
3. Usurps host machinery to synthesize capsid proteins and viral genetic material.
4. Virus particles spontaneously reassemble.
5. Enveloped virions exit and often destroy the host cell.
190
What happens to the viral capsid once it enters the host cell?
The phago-lysosome, full of degrading enzymes, busts open the viral capsid, freeing the nucleic acid.
## Footnote
This allows viral DNA to replicate using the host's machinery.
191
How do plants and insects respond to viral infections?
Plants and insects combat viral infections using gene silencing.
## Footnote
This mechanism treats a virus as an overexpressed gene, turning off viral protein production by chopping viral RNA into small pieces.
192
What is the role of anti-viral antibodies in mammalian host responses?
Anti-viral antibodies produced by the host immune system coat the virus capsid proteins, blocking the virus from binding to host cell membrane proteins.
## Footnote
This prevents cellular entry, although it is not foolproof.
193
True or False: Virus particles are alive outside host cells.
False
## Footnote
Virus particles are dead outside host cells and cannot be killed until they become metabolically active.
194
Fill in the blank: Viruses can replicate and produce new virions using the __________ of the host cell.
[cellular machinery]
195
What type of virus is the Influenza Virus?
An RNA virus that can rapidly, but randomly mutate
## Footnote
This rapid mutation is a key factor in its virulence.
196
What animals can Influenza A infect?
Birds, humans, and other animals
## Footnote
Influenza A is considered zoonotic.
197
What are the spike proteins of the Influenza Virus?
H (haemagglutinin) and N (neuraminidase) spike
## Footnote
These proteins bind to host cell membranes.
198
What can new mutated strains of Influenza cause?
Major epidemics
## Footnote
The mutations primarily target the H and N spike proteins.
199
What is Antigenic Drift?
Small, random mutations in the genes of influenza viruses that lead to changes in the surface proteins
## Footnote
It results in slower, smaller changes that our bodies can better manage.
200
How does Antigenic Shift differ from Antigenic Drift?
Antigenic Shift is an abrupt, major change in an influenza A virus that results in new H and/or N proteins
## Footnote
It is responsible for epidemics and pandemics and occurs much faster than drift.
201
What is SARS-CoV-2?
A respiratory virus that causes damage to lung tissue
## Footnote
The damage can be worse than the virus itself due to the body's immune response.
202
What are the four structural proteins of SARS-CoV-2?
* S (spike)
* E (envelope)
* M (membrane)
* N (nucleocapsid)
## Footnote
The spike protein binds to human host cell receptors.
203
How is SARS-CoV-2 transmitted?
Very easily transmitted through water vapor
## Footnote
This facilitates its spread in the environment.
204
What is zoonosis?
An infectious disease caused by a pathogen that has jumped from an animal to a human
## Footnote
Viral mutations can produce zoonotic viruses.
205
What can zoonotic antigenic shift produce?
New viral variants that produce more virulent viruses causing epidemics and pandemics
## Footnote
This mechanism is critical in the emergence of new diseases.
206
What is the purpose of vaccinations?
To induce an antiviral immune response to protect the host from severe viral disease
## Footnote
Vaccines are crucial in controlling viral outbreaks.
207
How do vaccines drive antigenic shift?
By introducing a selective agent (anti-viral antibodies) into the virus' environment
## Footnote
This creates Darwinian selection pressure on the virus.
208
What is ploidy?
Ploidy is the number of sets of chromosomes in a cell, or in the cells of an organism.
209
What are the two types of ploidy?
* Diploid
* Haploid
210
What defines diploid cells?
Diploid cells have 2 sets of chromosomes.
211
How many chromosomes do normal body cells in humans have?
46 chromosomes (23 pairs of chromosomes).
212
What defines haploid cells?
Haploid cells have 1 set of chromosomes.
213
What are gametes?
Gametes are haploid cells, specifically human sperm and eggs, which have 23 chromosomes.
214
What is a chromosome?
A chromosome is a single strand of DNA that is encoded with genes.
215
What are homologous chromosomes?
Homologous chromosomes are a pair where one chromosome comes from each parent.
216
Are homologous chromosomes identical?
No, they are not identical; they have different alleles for many genes.
217
What are alleles?
Alleles are 2 copies of the same gene (dominant or recessive).
218
What do homologous chromosomes have in common?
They have genes coding for the same characters in the same positions (loci) along their length.
219
How can the chromosomes of diploid organisms be arranged?
The chromosomes can be arranged in pairs according to size and shape.
220
What does biological sex refer to?
Biological sex refers to the sex based on X and Y chromosomes.
221
What is the chromosome composition of a female human?
2x X chromosomes.
222
What is the chromosome composition of a male human?
X & Y chromosomes.
223
What is a chromatid?
A chromatid is one of the two thread-like strands into which a chromosome divides during cell division.
224
What are sister chromatids?
Sister chromatids are the copies of a single chromosome that has been replicated during mitosis.
225
Are sister chromatids genetically identical?
Yes, sister chromatids are genetically identical.
226
What holds sister chromatids together?
Sister chromatids are held together by the centromere.
227
What is the source of homologous chromosomes?
From each parent.
228
What is the source of sister chromatids?
DNA replication (mitosis).
229
Do homologous chromosomes have identical DNA sequences?
No, they have different DNA sequences (alleles).
230
Are sister chromatids identical?
Yes, they are identical due to DNA replication.
231
What is the function of homologous chromosomes?
Genetic variation in meiosis.
232
What is the function of sister chromatids?
DNA replication (mitosis/meiosis).
233
What is the end result of mitosis?
2 new diploid daughter cells
## Footnote
Mitosis results in two identical daughter cells, each with the same diploid number of chromosomes as the original cell.
234
What does '2n' represent in the context of mitosis?
Diploid cells
## Footnote
'2n' indicates that the cell has two sets of chromosomes, one from each parent.
235
What happens during the S phase of mitosis?
DNA is replicated
## Footnote
DNA replication occurs in a semi-conservative manner, producing sister chromatids.
236
What is the chromosomal state at the G2 phase of mitosis?
4n
## Footnote
At G2, the cell has four copies of each chromosome due to DNA replication.
237
What is cytokinesis?
Division of the cytoplasm
## Footnote
Cytokinesis is the process that follows mitosis, resulting in the separation of the cell into two daughter cells.
238
How many rounds of division occur in meiosis?
2 rounds
## Footnote
Meiosis consists of meiosis I and meiosis II.
239
What occurs during meiosis I?
Separation of homologous chromosomes
## Footnote
Meiosis I is similar to mitosis but focuses on separating homologous chromosome pairs.
240
What happens during meiosis II?
Separation of sister chromatids
## Footnote
Meiosis II does not include an S phase and aims to split the existing DNA into gametes.
241
What type of cells are produced at the end of meiosis?
Haploid gamete sex cells
## Footnote
The resulting cells have half the number of chromosomes, essential for sexual reproduction.
242
What are the two main factors that result in genetic variation in offspring during meiosis?
* The behaviour of chromosomes
* The formation of haploid gametes
## Footnote
These factors contribute to genetic diversity in sexually reproducing populations.
243
What phenomenon can occur during chromosome condensation in mitosis?
Chromosomal breaks and crossing over
## Footnote
This can lead to genetic variation as segments of chromosomes may swap places.
244
True or False: Meiosis II has an S phase.
False
## Footnote
Meiosis II does not have an S phase because it does not require DNA replication.
245
Fill in the blank: In mitosis, the cell starts with _______ chromosomes in G1 phase.
2n
## Footnote
The G1 phase begins with diploid chromosomes.
246
What type of reproduction involves only one parent?
Asexual Reproduction
## Footnote
Asexual reproduction results in no genetic variation.
247
What is the key characteristic of sexual reproduction?
Offspring combine homologous chromosomes from 2 parents
## Footnote
Sexual reproduction only occurs in eukaryotes.
248
What are the two main processes involved in the complete sexual reproduction cycle?
Meiosis and Fertilisation
## Footnote
Meiosis forms haploid gametes, and fertilisation combines them to form a diploid zygote.
249
What type of cells are gametes produced by meiosis?
Haploid cells
## Footnote
Gametes are always haploid, containing n chromosomes.
250
What is formed after the fertilisation of two haploid gametes?
Diploid Zygote
## Footnote
The diploid zygote is the offspring resulting from fertilisation.
251
What is the initial type of cells that animals start with in sexual reproduction?
2n diploid cells
## Footnote
Animals undergo meiosis to produce haploid gametes.
252
What is the process called that results in the formation of four haploid cells from one diploid cell?
Meiosis
## Footnote
Meiosis halves the genetic content during sexual reproduction.
253
What is the sequence of events in animal sexual reproduction?
2n diploid cells → Meiosis → n gametes → Fertilisation → 2n zygote → Mitosis
## Footnote
This sequence leads to the growth of the organism.
254
In plants, what do diploid cells undergo to produce spores?
Meiosis
## Footnote
This results in haploid spores which lead to gamete formation.
255
What is the primary advantage of sexual reproduction?
Genetic variation among offspring
## Footnote
This allows for new gene combinations to adapt to changing environments.
256
What is random fertilisation?
The fusion of 1 male gamete with 1 female gamete
## Footnote
This process increases potential variation in zygotes.
257
True or False: Asexual reproduction provides genetic variation.
False
## Footnote
Asexual reproduction involves only one parent, leading to no genetic variation.
258
Fill in the blank: The process of _______ leads to the formation of a diploid zygote from two haploid gametes.
Fertilisation
## Footnote
Fertilisation is crucial for restoring the diploid state in the offspring.
259
What does mitosis do after fertilisation in both animals and plants?
Grows the diploid zygote into a new individual
## Footnote
Mitosis is essential for the development of the organism.
260
What is one benefit of sexual reproduction concerning gene combinations?
Spread of beneficial genes
## Footnote
This can enhance survival and adaptability within a population.
261
What are the two main types of reproduction compared?
Asexual Reproduction and Sexual Reproduction
## Footnote
The comparison highlights differences in genetic variation and processes.
