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Biology Topic 5 - 8 > Topic 5-8 > Flashcards

Topic 5-8 Flashcards

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1
Q

What are thylakoid membranes?

A

Folded membranes containing photosynthetic proteins and electron carrier proteins involved in light-dependent reactions (LDR)

Thylakoid membranes are crucial for capturing light energy during photosynthesis.

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2
Q

What is the stroma in chloroplasts?

A

The fluid center of chloroplasts that contains enzymes involved in the light-independent reactions (LIR)

The stroma is where the Calvin Cycle takes place.

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3
Q

What are the two membranes surrounding chloroplasts?

A

Inner and outer membrane

These membranes control what enters and leaves the organelle.

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4
Q

What occurs during the light-dependent reactions (LDR)?

A

Occurs on thylakoid membranes, requires light, and produces ATP and reduced NADP

LDR is the first stage of photosynthesis.

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5
Q

What is photolysis?

A

The process where light energy splits water into O2, H+, and e-

H+ is picked up by NADP to form reduced NADP.

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6
Q

What happens during photoionisation of chlorophyll?

A

Light energy excites electrons in chlorophyll, causing them to leave the molecule

This process ionises chlorophyll.

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7
Q

What is chemiosmosis?

A

The process where electrons move along proteins in the thylakoid membrane, creating an electrochemical gradient that produces ATP

Proton movement through ATP synthase during this process generates ATP.

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8
Q

What is the Calvin Cycle?

A

The light-independent reaction (LIR) that occurs in the stroma, producing hexose sugar from CO2, reduced NADP, and ATP

This cycle involves several steps including the conversion of CO2 to glycerate 3 phosphate (GP).

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9
Q

What is glycolysis?

A

The first stage of aerobic respiration occurring in the cytoplasm, converting glucose to pyruvate and producing a net of 2 ATP

This process involves phosphorylation and oxidation of glucose.

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10
Q

What happens in the link reaction of aerobic respiration?

A

Pyruvate is converted into acetyl CoA in the mitochondrial matrix

This reaction occurs twice for every glucose molecule.

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11
Q

What is produced during the Krebs Cycle?

A

Generates reduced coenzymes, 2 ATP, and releases 4 carbon dioxides

This cycle involves a series of redox reactions.

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12
Q

What is oxidative phosphorylation?

A

The stage where most ATP is synthesized, using oxygen as the final electron acceptor

This process occurs in the mitochondrial inner membrane.

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13
Q

What is anaerobic respiration?

A

Respiration that occurs in the absence of oxygen, producing ethanol and carbon dioxide in plants or lactate in animals

This process allows for continued ATP production despite the lack of oxygen.

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14
Q

What is Gross Primary Production (GPP)?

A

The total chemical energy store in plant biomass resulting from photosynthesis

GPP is measured in a given area or volume.

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15
Q

What does Net Primary Production (NPP) represent?

A

The chemical energy store in plant biomass after accounting for energy lost during respiration

Calculated as NPP = GPP - R.

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16
Q

What is nitrogen fixation?

A

The conversion of atmospheric nitrogen gas into nitrogen-containing compounds by nitrogen-fixing bacteria

This process is essential for making nitrogen available to plants.

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17
Q

What occurs during ammonification?

A

Nitrogen compounds in waste products and dead organisms are converted into ammonia

This ammonia can then form ammonium ions in the soil.

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18
Q

What is nitrification?

A

The conversion of ammonium ions into nitrates by nitrifying bacteria

This process is crucial for nitrogen availability in the soil.

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19
Q

What is denitrification?

A

The process where denitrifying bacteria convert nitrates back into nitrogen gas

This occurs under anaerobic conditions.

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20
Q

What is the phosphorous cycle?

A

The movement of phosphorus from rocks to soil and water, then to plants and consumers, and back to the soil or water during decomposition

This cycle is essential for plant growth.

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21
Q

What are the two types of fertilizers?

A

Natural (manure) and artificial (inorganic chemicals)

Each type has its advantages and disadvantages regarding nutrient control and environmental impact.

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22
Q

What is tropism?

A

A plant’s growth response to stimuli, which can be positive or negative

Examples include phototropism and gravitropism.

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23
Q

What is phototropism?

A

A plant’s growth response to light, where shoots grow towards light (positive) and roots grow away from light (negative)

Indoleacetic acid (IAA) plays a key role in this response.

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24
Q

What is gravitropism?

A

A plant’s growth response to gravity, where shoots grow upwards (negative gravitropism) and roots grow downwards (positive gravitropism)

IAA distribution affects cell elongation.

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25
What is a reflex?
A rapid, automatic response to protect from danger ## Footnote The reflex arc consists of three neurons.
26
What are taxes?
Movement of an organism towards (positive taxis) or away from (negative taxis) a stimulus ## Footnote This response involves the entire body of the organism.
27
What is kinesis?
An organism's change in speed of movement and direction in response to a stimulus ## Footnote Unlike taxis, kinesis does not involve directional movement towards or away from a stimulus.
28
What is the Pacinian Corpuscle?
A pressure receptor located deep in the skin, primarily in fingers and feet ## Footnote It contains stretch-mediated sodium channels that open upon deformation.
29
What are rod cells?
Photoreceptors that process images in black and white and can detect low light intensity ## Footnote They have low visual acuity due to retinal convergence.
30
What are cone cells?
Photoreceptors that process color images and require high light intensity to generate action potentials ## Footnote There are three types of cone cells, each sensitive to different wavelengths of light.
31
What is a myelinated motor neurone?
A neurone with a myelin sheath formed by Schwann cells, which facilitates rapid impulse conduction ## Footnote Nodes of Ranvier are present between myelin sheaths.
32
What is a synapse?
The gap between the end of an axon and the dendrite of another neuron where neurotransmission occurs ## Footnote Action potentials are transmitted via neurotransmitters across the synaptic cleft.
33
What is the function of acetylcholinesterase at cholinergic synapses?
To degrade acetylcholine into choline and acetate for recycling ## Footnote This process prevents continuous stimulation of the postsynaptic neuron.
34
What is summation in synapses?
The rapid build-up of neurotransmitters to generate an action potential, either through spatial or temporal summation ## Footnote Spatial summation involves multiple neurons, while temporal summation involves repeated release from one neuron.
35
What happens in an inhibitory synapse?
Chloride ions move into the postsynaptic neuron and potassium ions move out, making action potentials less likely ## Footnote This leads to hyperpolarization of the membrane.
36
What is a neuromuscular junction?
The synapse between a motor neuron and a muscle fiber, facilitating muscle contraction ## Footnote It is similar to a cholinergic synapse but specifically connects motor neurons to muscles.
37
What distinguishes a neuromuscular junction from a cholinergic synapse?
Neuromuscular junctions are unidirectional, only excitatory, and connect motor neurons to muscles ## Footnote Cholinergic synapses can be excitatory or inhibitory and connect two neurons.
38
What is the role of muscles in movement?
They act in antagonistic pairs against an incompressible skeleton to create movement ## Footnote Muscle movements can be automatic as part of reflex responses.
39
What is a Cholinergic Synapse?
A synapse that is unidirectional, could be excitatory or inhibitory, connects two neurons, generates a new action potential in the next neuron, and involves acetylcholine binding to receptors on the post-synaptic membrane.
40
What are antagonistic muscle pairs?
Muscles that act against each other to create movement, can be automatic in reflexes or controlled by conscious thought.
41
What are myofibrils?
Structures made up of fused cells that share nuclei and cytoplasm, known as sarcoplasm, and contain a high number of mitochondria.
42
What is a sarcomere?
The basic contractile unit of muscle fibers, made up of myofibrils that consist of myosin and actin.
43
What triggers the release of calcium in muscle contraction?
The action potential reaching the sarcoplasmic reticulum opens voltage-gated calcium channels.
44
What is the role of calcium in muscle contraction?
Calcium triggers tropomyosin to move, exposing myosin binding sites on actin.
45
What is the difference between slow twitch and fast twitch muscle fibers?
Slow twitch fibers are darker due to more myoglobin; fast twitch fibers have more phosphocreatine and are lighter.
46
What is the A band in muscle fibers?
The length of myosin in the middle of a sarcomere, which remains constant.
47
What is the sinoatrial node?
The natural pacemaker of the heart located in the right atrium wall where depolarization starts.
48
What is the function of the autonomic nervous system in heart rate regulation?
It includes an acceleratory part and an inhibitory center that regulate heart rate through neurotransmitters like acetylcholine and noradrenaline.
49
What is the role of insulin in glucose metabolism?
Insulin binds to receptors on muscle/adipose cells, activating a cascade that promotes glucose uptake and glycogenesis.
50
What is glucagon's role in energy metabolism?
Glucagon binds to receptors to activate adenylate cyclase, promoting glycogenolysis and gluconeogenesis.
51
Fill in the blank: Glycogenesis is the process of converting _______ into glycogen.
glucose
52
What is the function of the kidney in osmoregulation?
The kidney filters blood, reabsorbs glucose and water, and regulates water loss through the action of ADH.
53
What are the two types of speciation?
* Allopatric speciation * Sympatric speciation
54
What is stabilizing selection?
A type of selection that favors intermediate variants and acts against extreme phenotypes.
55
What is the primary source of genetic variation?
Mutation.
56
What is genetic drift?
A change in allele frequency within a population between generations, with a more significant impact in smaller populations.
57
What is the difference between interspecific and intraspecific competition?
* Interspecific competition: competition between different species * Intraspecific competition: competition within the same species
58
What is a gene mutation?
A change in the DNA base sequence of a gene.
59
What are the types of gene mutations?
* Addition * Deletion * Substitution * Inversion
60
What are totipotent stem cells?
Stem cells that can divide to produce any type of body cell, occurring only in early mammalian embryos.
61
What is the role of oestrogen in gene transcription?
Oestrogen binds to a receptor site on transcription factors, changing their shape to initiate transcription.
62
What effect does increased methylation have on transcription?
It inhibits transcription by preventing transcription factors from binding to DNA.
63
What is RNA interference (RNAi)?
A process that destroys transcribed mRNA before it is translated, inhibiting gene expression.
64
What characterizes benign tumors?
Grow very large at a slow rate and do not invade surrounding tissues.
65
What is RNA interference (RNAi)?
Inhibition of translation of mRNA produced from target genes by destruction of transcribed mRNA using small interfering RNA (siRNA) ## Footnote RNAi is a biological process in which RNA molecules inhibit gene expression or translation by neutralizing targeted mRNA molecules.
66
What causes cancer?
Mutations in genes that regulate mitosis leading to uncontrollable cell division and tumours ## Footnote Cancer can arise from both inherited mutations and environmental factors.
67
Define benign tumours.
Non-cancerous tumours that grow slowly, produce adhesive molecules, and are often encapsulated ## Footnote Benign tumours are usually not life-threatening and can often be removed surgically.
68
What characterizes malignant tumours?
Cancerous tumours that grow rapidly, can metastasise, and are not encapsulated ## Footnote Malignant tumours often require removal and may need chemotherapy or radiotherapy.
69
What are oncogenes?
Mutated versions of proto-oncogenes that can lead to uncontrolled cell division ## Footnote Oncogenes promote cell growth and division when activated.
70
What is the function of tumour suppressor genes?
Produce proteins that slow down cell division and induce cell death if DNA errors are detected ## Footnote Mutations in these genes can lead to unchecked cell division.
71
What is reverse transcription?
The process where an enzyme makes DNA copies from mRNA ## Footnote This process is utilized by certain viruses, such as HIV.
72
What is the advantage of cDNA?
cDNA is intron-free as it is based on the mRNA template ## Footnote This makes it suitable for expression in prokaryotic cells.
73
What are restriction endonucleases?
Enzymes that cut DNA at specific locations, used by bacteria as a defense mechanism ## Footnote They can create blunt ends or sticky ends based on how they cut the DNA.
74
What is a gene machine?
A computerized device that creates DNA fragments by assembling oligonucleotides ## Footnote This process is quick, accurate, and can produce intron-free DNA.
75
What are the steps of PCR?
1. Denaturation at 95°C 2. Annealing at 55°C 3. Synthesis at 72°C ## Footnote PCR is used to amplify DNA, making it easier to study.
76
What is genetic fingerprinting?
A technique involving collection, extraction, digestion, separation, hybridisation, and development of DNA samples ## Footnote It is used for identifying individuals based on their unique DNA patterns.
77
Fill in the blank: DNA probes are ______.
short, single stranded, complementary sequences to VNTRs ## Footnote Probes can be labeled for detection using radioactive or fluorescent markers.
78
What is gel electrophoresis?
A method to separate DNA fragments based on size by applying an electrical voltage to agar gel ## Footnote Smaller DNA fragments move faster and further through the gel.
79
True or False: Malignant tumours are encapsulated.
False ## Footnote Malignant tumours are not encapsulated and can invade surrounding tissues.

Biology Topic 5 - 8 (1 decks)

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