Module 1: Information Transfer Flashcards
(181 cards)
1
Q
What are prokaryotes?
A
Prokaryotes are organisms with simple cells that lack a nucleus, such as bacteria.
1
Q
What are eukaryotes?
A
Eukaryotes are organisms with complex cells that contain a nucleus, such as plants and animals.
2
Q
Why is carbon important in biology?
A
Carbon forms stable bonds with other elements, allowing the creation of complex organic molecules essential for life.
3
Q
What are hydrophobic molecules?
A
Hydrophobic molecules are non-polar and do not mix well with water; they repel water.
4
Q
What are hydrophilic molecules?
A
Hydrophilic molecules are polar and interact readily with water due to their ability to form hydrogen bonds.
5
Q
What are monosaccharides?
A
Monosaccharides are simple sugars like glucose that serve as building blocks for carbohydrates.
6
Q
What are disaccharides?
A
Disaccharides are carbohydrates composed of two monosaccharide units, such as sucrose.
7
Q
What are polysaccharides?
A
Polysaccharides are long chains of monosaccharides, like starch and cellulose.
8
Q
What is the function of starch?
A
Starch serves as an energy storage molecule in plants.
9
Q
What is cellulose?
A
Cellulose is a structural polysaccharide found in plant cell walls.
10
Q
What are lipids?
A
Lipids are molecules that include fats, oils, and waxes, which are important for energy storage and protection.
11
Q
What is the role of phospholipids in cell membranes?
A
Phospholipids form a bilayer that acts as a barrier to control the movement of substances in and out of cells.
12
Q
What are amino acids?
A
Amino acids are the building blocks of proteins, each with an amino group, a carboxyl group, and a variable side chain.
13
Q
What is a peptide bond?
A
A peptide bond is a covalent bond formed between the amino group of one amino acid and the carboxyl group of another.
14
Q
What is the difference between DNA and RNA?
A
DNA contains thymine, is double-stranded, and stores genetic information, while RNA contains uracil, is single-stranded, and helps in protein synthesis.
15
Q
What is the central dogma of molecular biology?
A
The central dogma describes the flow of genetic information from DNA to RNA to protein.
16
Q
How does the structure of bacterial genomes differ from eukaryotic genomes?
A
Bacterial genomes are circular and relatively small, whereas eukaryotic genomes are linear, larger, and organised into chromosomes.
17
Q
What is the function of enzymes in biological systems?
A
Enzymes act as biological catalysts, speeding up chemical reactions in cells without being consumed in the process.
18
Q
What is enzyme specificity?
A
Enzyme specificity refers to the ability of an enzyme to choose the correct substrate from a group of similar chemical molecules.
19
Q
What are the four main types of macromolecules in cells?
A
Carbohydrates, lipids, proteins, and nucleic acids.
20
Q
What is the role of ATP in cellular processes?
A
ATP (adenosine triphosphate) provides energy for cellular activities by releasing a phosphate group.
21
Q
What are the stages of cellular respiration?
A
Glycolysis, the Krebs cycle, and electron transport chain
22
Q
What is glycolysis and where does it occur?
A
Glycolysis occurs in the cytoplasm and is the first stage of cellular respiration that breaks down one molecule of glucose into two molecules of pyruvate, ATP and NADH.
23
Q
What is the Krebs cycle and where does it occur?
A
The Krebs cycle occurs in the mitochondria and is the second stage of cellular respiration that processes acetyl-CoA to produce three molecules of NADH, one FADH₂ and ATP and two CO₂.
24
What is the electron transport chain and where does it occur?
The electron transport chain occurs in the inner mitochondrial membrane and is the third stage of cellular respiration where electrons from NADH and FADH₂ are transferred through a series of proteins in the inner mitochondrial membrane to produce ATP.
25
How does the electron transport chain generate ATP?
The ETC generates ATP by creating a proton gradient across the inner mitochondrial membrane. The flow of protons back through ATP synthase drives the conversion of ADP and inorganic phosphate into ATP.
26
What is the difference between aerobic and anaerobic respiration?
Aerobic respiration requires oxygen and produces more ATP, while anaerobic respiration does not require oxygen and produces less ATP, along with byproducts like lactic acid or ethanol.
27
What are the two main stages of photosynthesis?
Light-dependent reactions and the Calvin cycle (light-independent reactions).
28
What is active transport?
Active transport is the movement of molecules across a cell membrane against their concentration gradient, requiring energy.
29
What is apoptosis?
Apoptosis is programmed cell death, a controlled process that eliminates damaged or unnecessary cells.
30
What is the role of DNA polymerase I?
DNA polymerase I catalyses the addition of successive nucleotide units to the end of the DNA strand
31
What is a codon?
A codon is a sequence of three nucleotides in mRNA that codes for a specific amino acid or a stop signal during protein synthesis.
32
What is translation in protein synthesis?
Translation is the process by which the mRNA sequence is used to build a polypeptide chain of amino acids at the ribosome.
33
What is the role of chaperone proteins?
Chaperone proteins assist in the proper folding of other proteins and help prevent misfolding or aggregation.
34
What defines the directionality and structure of nucleic acid polymers?
Synthesised in one direction only, written from 5' to 3', and have a common phosphate-sugar backbone with a negative charge, which is hydrophilic.
35
What distinguishes ribose from deoxyribose in nucleic acids?
Ribose has an OH group at the 2' carbon, while deoxyribose has just an H group at the 2' carbon.
36
How are peptide bonds formed between amino acids?
Peptide bonds are formed through a condensation mechanism where two amino acids combine, creating a dipeptide. This process is energetically unfavourable.
37
How do bacterial genomes differ from eukaryotic genomes?
Bacterial genomes are typically circular and relatively small, while eukaryotic genomes are larger, linear, and condensed wrapped around histone proteins.
38
What is the significance of epigenetic regulation?
Epigenetic regulation involves chemical modifications to DNA and proteins that alter gene expression without changing the DNA sequence itself. These modifications can be inherited through generations.
39
What is a point mutation?
A point mutation is a change in a single base pair in the DNA sequence.
40
What is a silent mutation and what is its effect?
A silent mutation is a change in the DNA sequence that does not alter the amino acid sequence of the resulting protein.
41
What is a nonsense mutation and what is its effect on protein synthesis?
A nonsense mutation creates a premature stop codon in the DNA sequence, leading to a truncated and usually nonfunctional protein.
42
What is an insertion mutation and what is its impact?
An insertion mutation involves the addition of one or more base pairs into the DNA sequence, which can lead to changes in the amino acid sequence or cause a frameshift
43
What is a deletion mutation and what are its potential consequences?
A deletion mutation involves the removal of one or more base pairs from the DNA sequence, which can result in a frameshift or loss of important protein regions.
44
What is a missense mutation and how does it affect the protein?
A missense mutation is a change in the DNA sequence that alters one amino acid in the protein, potentially affecting its function.
45
What is a frameshift mutation and what are its effects on protein coding?
A frameshift mutation occurs due to insertions or deletions of base pairs that alter the reading frame of the codons, leading to changes in the amino acid sequence and often producing a nonfunctional protein.
46
What is a duplication mutation and how does it affect the DNA sequence?
A duplication mutation involves the repetition of a segment of DNA, which can lead to an increased dosage of the genes within the duplicated region and potential disruptions in gene function.
47
How does DNA polymerase add nucleotides during DNA replication?
DNA polymerase adds nucleotide monophosphates to the 3’OH end of the growing chain
48
How is bacterial DNA replication different from eukaryotic DNA replication?
Bacterial DNA replication involves circular genomes and requires copying both strands of the DNA, while eukaryotic DNA replication involves linear chromosomes.
49
What is the function of topoisomerase in DNA replication?
Topoisomerase enzymes cut DNA strands to relieve supercoiling caused by unwinding and allow the DNA to unwind and rejoin.
50
What are the five steps during the initiation phase of DNA replication?
The origin of replication is recognised, DNA binding proteins open the site, DNA helicase unwinds the DNA, topoisomerase prevents supercoiling, and single-stranded binding proteins protect the single strands.
51
How does leading strand replication differ from lagging strand replication?
Leading strand replication involves continuous synthesis towards the replication fork, while lagging strand replication involves discontinuous synthesis with multiple primers and Okazaki fragments.
52
What are the three steps during the termination phase of DNA replication?
DNA polymerase III reaches the RNA primer, DNA polymerase I removes the primer and replaces it with DNA, and DNA ligase joins the ends of the DNA.
53
How does transcription differ from DNA replication?
Transcription makes an RNA copy from a DNA template, does not require a primer, has limited proofreading, and only transcribes small sections of the genome.
54
What are the key steps in transcription initiation?
RNA polymerase binds to the promoter region and starts transcribing downstream
55
What are the key steps in transcription termination?
Transcription termination occurs at the terminator site, where a G/C rich region forms a pin structure, causing RNA polymerase and RNA to be released.
56
How can gene expression frequencies vary?
Genes can be expressed at different frequencies depending on promoter strength, which influences the amount of RNA produced.
57
What do repressors do in gene expression regulation?
Repressors block proteins from binding to the DNA, thereby reducing or preventing gene expression.
58
How do accelerators/activators influence gene expression?
Accelerators or activators are used when there is a weak promoter. They change the physical properties of the promoter to make it more favorable for binding and enhance gene expression.
59
What are the main components of a tRNA molecule?
A tRNA molecule has a cloverleaf shape, with the amino acid attachment at the 3' end and an anticodon at the opposite end, which is complementary to the mRNA codon.
60
What are the three steps during the initiation stage of protein synthesis?
The small ribosomal subunit binds to mRNA and met-tRNA, identifying the start codon with the help of extra mRNA sequences, and then the large ribosomal subunit binds.
61
What are the four steps during the elongation stage of protein synthesis?
aa-tRNA guided by anticodon/codon matching brings activated amino acids next to each other, peptide bonds are formed by peptidyl transferase, tRNA is released, and the ribosome moves to the next codon.
62
What are the four steps of termination in protein synthesis?
When a stop codon is reached, no matching tRNA is available, a release factor binds, peptidyl transferase adds water to release the polypeptide, and the machinery disassembles.
63
What is primary protein structure?
Primary protein structure refers to the sequence of amino acids in a polypeptide chain.
64
What is secondary protein structure?
Secondary protein structure involves local structures such as alpha helices and beta sheets formed by backbone-backbone hydrogen bonding interactions.
65
How is tertiary protein structure formed?
Tertiary protein structure is the overall 3D arrangement of a polypeptide chain, stabilized by various interactions including hydrogen bonds, ionic interactions, and hydrophobic effects.
66
What defines quaternary protein structure?
Quaternary protein structure involves the organisation and interaction of multiple polypeptide subunits to form a functional protein complex.
67
What is the general structure of an alpha helix in protein secondary structure?
An alpha helix is a right-handed coil where the backbone forms a helical shape
68
Which organelle is responsible for ATP production in cells?
Mitochondria
69
What is glycolysis?
The process that converts glucose into pyruvate
70
What occurs during prophase?
DNA and proteins in the nucleus, coil and compact, forming visible chromosomes
71
What occurs during metaphase?
Chromosomes condense and move to the center of the cell, aligning along the metaphase plate, which is the equatorial plane
72
What occurs during anaphase?
The sister chromatids break apart, and the chromosomes begin moving to opposite ends of the cell
73
What occurs during telophase?
A nuclear membrane forms around each set of chromosomes, separating the nuclear DNA from the cytoplasm
74
What is the main function of lysosomes?
Digestion and waste removal
75
What does the nuclear envelope do?
Controls the movement of molecules, ions, and RNA between the nucleoplasm and cytoplasm
76
What does the rough endoplasmic reticulum do?
Modifies proteins and synthesises phospholipids
77
What does the smooth endoplasmic reticulum do?
Synthesises carbohydrates, lipids, and steroid hormones
78
What does the golgi apparatus do?
Sorts, tags, packages, and distributes lipids and proteins
79
What does the vesicles do?
Allow the exchange of membrane components with the plasma membrane
80
What is the endomembrane system?
A group of membranes and organelles in eukaryotic cells that works together to modify, package, and transport lipids and proteins
81
Where does the calvin cycle occur?
Stroma
82
What is the stroma of a chloraplast?
The fluid-filled space inside a chloroplast
83
What is the primary role of NADH in cellular respiration?
Serve as an electron carrier
84
Where does the Krebs Cycle take place during cellular respiration?
Occurs in the mitochondrial matrix
85
Which process generates the most ATP?
Electron transport chain
86
What is osmosis?
The movement of a solute from low to high concentration
87
What is the 'energy currency' in cells?
ATP
88
What does the term allele refer to?
Different forms of a gene
89
What makes phospholipids unique?
Their amphipathic properties
Hydrophilic head - polar
Hydrophobic tail - non-polar
90
Why is the Calvin Cycle important?
Transforms inorganic carbon into organic compounds
91
What is the general process of the Calvin Cycle?
Uses CO2 and energy from ATP and NADPH which was generated during the light dependent stage to produce glucose and other sugars
92
What is the detailed process of the Calvin Cycle (6 steps)?
Circular process
1. Carbon fixation - CO2 +RuBP = RuBisCO
2. RuBisCO splits into 3-PGA
3. 3-PGA phosphorylated by ATP - ATP converted to ADP
4. 3-PGA reduced by NADPH to form G3P - NADPH converted to NADP+ and H+
5. G3P used to produce glucose and other sugars
6. Regeneration of RuBP by ATP - ATP converted to ADP
93
What are the downfalls of the C3 calvin cycle?
Rubisco should be using CO2 as the substrate, but it can also use oxygen as its substrate
Losing about 20% productivity
94
What are the two main solutions for photorespiration?
C4 and CAM photosynthesis
95
How is C4 photosynthesis different?
Is a series of metabolic and structural adjustments exploiting PEPC to concentrate CO2 around Rubisco
96
How is CAM photosynthesis different?
Stomata open during the night closed during the day reduced the amount of water lost. CO2 converts to malate in the vacuole during the night which decarbonates during the day.
97
What is the equation for the calvin cycle?
3CO2 + 9ATP + 6NADPH + 6H*
-> C3H6O3 (phosphate) + 9ADP + 8P + 6NADP* + 3H2O
98
What is anabolism?
Requires energy for small molecules to assemble into larger ones
99
What is catabolism?
Energy is released when large molecules break down into small ones
100
What is a methanotroph?
Prokaryotes that consume methane and produce carbon dioxide resulting in net positive environmental impact.
101
What is the role of DNA polymerase II?
Catalyses the elongation of the DNA
102
What is the role of helicase?
Unwind short segments of DNA just ahead of the replication fork
103
What is the role of topoisomerase?
Helps helicase unwinding the DNA by cutting and ligating the strand to prevent supercoiling
104
What is the role of DNA ligase?
Joins Okazaki fragments by forming phosphodiester bonds
105
What is phagocytosis?
The engulfing of bacteria or cell material into the cell via a vacuole
106
What is pinocytosis?
The movement of water and solute from the outside to the inside of the cell via vesicles
107
What is endocytosis?
The movement of specific molecules from the exterior into the interior via vesicles
108
What is exocytosis?
The releasing of molecules from the inside of the cell to the exterior
109
What is the genome?
DNA
110
What is the transcriptome?
RNA
111
What is the proteome?
Proteins
112
What is responsible for heat loss in a lotus flower?
Alternative oxidase and uncoupling protein to reduce ATP production efficiency and so energy is wasted as heat
113
How does bacteria reproduce?
Binary fission
113
What is the role of ssDNA?
Stops DNA rebinding and protects it. Single stranded binding proteins bind to the bases to protect them and prevent hairpins.
114
What is the role of transcription factors?
To facilitate the binding of RNA polymerase to the single-stranded DNA
115
What are the three main components of connective tissues?
Fibres, cells and ground substances
116
What is the role of alternative oxidase?
Is a safety valve to reduce the amount of ATP produced by releasing energy in the form of heat
117
What is acetyl-CoA used for and where does it come from?
Pyruvate is converted into acetyl-CoA and is processed in the Krebs cycle
118
How is pyruvate converted to acetyl-CoA?
Pyruvate undergoes link reaction and becomes acetyl by losing a CO2
119
What type of bonding is essential in stabilising the secondary structure of proteins?
Hydrogen bonding between the backbone atoms
120
In an alpha helix, where do the side chains of amino acids point?
They point outward from the helix.
121
How do the hydrogen bonds form in a beta sheet?
They occur between the strands of the beta sheet
122
What is the direction of beta strands in a beta sheet?
Beta strands can be parallel, antiparallel, or mixed
123
What is the primary driving force for the folding of proteins into their tertiary structure?
The hydrophobic effect
124
Which factors are crucial for maintaining a protein’s tertiary structure?
pH, temperature, and solvent conditions
125
What is an exergonic reaction?
A reaction that releases energy and is favourable
126
What is an endergonic reaction?
A reaction that absorbs energy and is unfavourable
127
How does ATP power transport across the cell membrane
It phosphorylates transmembrane proteins, causing them to change shape
128
What is a purine?
Double ring structures such as A and G
129
What is a pyrimidine?
Single ring structures such as C, T and U
130
What is photophosphorylation?
The process by which plants convert light energy into ATP
131
Where does photophosphorylation occur?
In the thylakoid membranes of the chloroplast
132
When does non-cyclic photophosphorylation occur?
When the cell needs both ATP and NADPH
133
When does cyclic photophosphorylation occur?
When there is a high demand for ATP and there is sufficient NADPH
134
What is unique about non-cyclic photophosphorylation?
Electrons that have been removes from the PSII are replaced by electrons from water and electrons are transferred to NADP+ converting it to NADPH
135
What is unique about cyclic photophosphorylation?
Instead of electrons being transferred to NADP+ it is cycled back to PSI
136
What does the lock and key model suggest about enzymes?
A rigid fit, without shape adjustment
137
What does the induced fit model suggest about enzymes?
Enzyme's active site can adjust to improve binding with a substrate
138
What does the selection model suggest about enzymes?
That there are multiple forms of the enzyme but only one can bind with the substrate
139
What is the primary function of the stroma?
To synthesise glucose during the Calvin cycle
140
What part of the chloroplast contains the chlorophyll content?
The thylakoid membrane
141
What occurs in the thylakoid membranes?
The light dependent reactions
142
Where is fat stored in the body?
In adipose tissue
143
What is omentum?
Is a membrane which sits over the small intestine and is where most fats are stored
144
How did the nucleus evolve in eukaryotic cells?
The cell membrane folding inward to form internal compartments.
145
How did mitochondria likely evolve in eukaryotic cells?
An aerobic prokaryotic cell was engulfed
146
What do motor proteins do in relation to the mitochondria?
They transport the mitochondria along microtubules
147
What function does mitochondria have in sperm cells?
Organised to power the movement of the sperm tail by wrapping around microtubules.
148
What are the three major biological functions of mitochondria?
ATP synthesis, steroid hormone production, and apoptosis regulation.
149
What are the three main components of the cytoskeleton and what are they made of?
Microfilaments (actin), microtubules (tubulin) and intermediated filaments (keratin)
150
What is epithelium tissue?
Tissue which is an interface between the animal and the environment
151
What is connective tissue?
Tissue which connects the epithelium to nervous and muscle tissue
152
What is the role of epithelium tissue?
It controls the movement of molecules in and out
153
What is the structure of simple epithelium?
One cell thick
154
What is the structure of stratified epithelium?
Many layers thick
155
What is the structure of pseudo stratified?
One cell thick but looks multiple layers thick due to the uneven placement of the nuclei
156
What is the shape of squamous cells in the epithelial?
Squashed cells
157
What is the shape of cubodial cells in the epithelial?
Cubic cells
158
What is the shape of columnar cells in the epithelial?
Column cells
159
What is the top of epithelia called?
Apical
160
What is the bottom of epithelia called?
Basal
161
What is the main function of the tight junctions in epithelial cells?
To create a waterproof seal
162
What is a desmosome?
Plates on the side and bottom of epithelial cells which interlock like velcro
163
Which of the following structures connects desmosomes to the basal lamina?
Hemidesmosomes
164
What are cadherins?
Proteins that interlock desmosomes
165
What are the characteristics of skeletal muscle tissue?
- Long non branched fibres
- Striated
- Multiple nuclei visible
- Movement is voluntary
166
What are the characteristics of cardiac muscle tissue?
- Branching fibres
- Striated
- Joined very tightly by intercalated disks
- One nuclei per cell
- Involuntary movement
167
What are the characteristics of smooth muscle tissue?
- Spindle shaped
- None striated
- Involuntary movement
- Lines every single hollow organ except the heart
168
What are the three types of muscle tissue?
Skeletal, cardiac and smooth
169
What causes striations in muscle tissue?
The overlapping of the proteins actin and myosin
170
How do steroids signal?
Signals can pass directly through the cell membrane, bind to a receptor, and enter the nucleus to activate genes
171
How do protein hormones signal?
Goes to nucleus and triggers transcription and translation
or goes to the cytoplasm and controls enzymes or cytoskeleton
172
How do neurotransmitters signal?
They bind to receptors that open ion channels in the cell membrane
173
Who is credited for the term "cell" and how did this come about?
Robert Hooke whilst observing the microscopic structure of blue moulds
174
Who discovered bacteria and protists?
Antonie van Leeuwenhoek
175
Who, how and when was penicillin discovered?
Alexander Fleming accidentally discovered that the mould penicillin killed bacteria in 1928
176
Who supported the spontaneous generation theory?
John Needham
177
What are obligate pathogens?
Pathogens which always cause disease
178
What are opportunistic pathogens?
Pathogens which cause diseases under specific conditions
179
What are bacteriophages?
Are viruses that infect and cause disease in bacteria
