Paper 2: Advanced Info Flashcards
1
Q
PET scans
A
* Patient injected with radiotracer.
* More glucose is required in places with higher activity.
* Only done once or twice a year.
* Expensive.
2
Q
How does age impact your likelihood to develop CVD?
A
Increases with age as plaque build up happens very slowly over time.
3
Q
What is the definition for dominant
A
An alleles who’s characteristic appears in the phenotype even when there’s only one copy.
4
Q
MRI scans
A
Magnetic field and radio wavesExamines tissues in small sections with thin slices which form 3D images.Produce finely detailed images of brain structures with better resolution than CT scans.
5
Q
What does the circular DNA of a prokaryotic cell do and what is it made up of?
A
They are one long coiled up strand and are not attached to any histone proteins.
6
Q
What is the DNA coding strand also known as?
A
The sense strand
7
Q
Draw a Relay neurone
A
* Dendrites
* Axon
* Terminal branches
* Cell body not external in between Schwann cells
* Large number of connections to other nerve cells
8
Q
How are sperm cells specialised for their function?
A
Lots of mitochondria provide energy for tail movement.Acrosome contains digestive enzymes to break down the egg cells zona pellucida and enable sperm to penetrate the egg.Flagellum allows sperm to swim towards egg cell.
9
Q
How does MDMA (ecstasy) work?
A
MDMA increases the level of serotonin in the brain.Usually serotonin is taken back into a presynaptic neurone after triggering an action potential to be used again.MDMA increases the level of serotonin by inhibiting the reuptake of serotonin into presynaptic neurones. It binds and blocks the reuptake proteins on the presynaptic membrane.MDMA also triggers the release of serotonin from presynaptic neurones.This means that serotonin levels stay high in the synapse and cause depolarisation of the post synaptic neurones in parts of the brain that control mood.So the effect is mood elevation.
10
Q
What is meant by totipotency?
A
The ability to produce all the specialised cells in an organism and extraembryonic cells eg placenta and umbilical cord.
11
Q
How does gravity impact plants growth?
A
Ensuring that developing shoots reach the light while roots grow in the soil.
12
Q
What the the social and ethical issues of PGD
A
Find out about other characterisitcs leading to concerns in the future that it could create designer baies. False results could provide incorrect information.
13
Q
How do SSRI’s work?
A
Selective serotonin reuptake inhibitors increase serotonin levels by preventing its reuptake at synapses.
14
Q
What does the rough ER do?
A
Folds and processes proteins that have been made at the ribosomes.
15
Q
What is the basic structure of an amino acid? and draw one
A
16
Q
What is deep vein thrombosis?
A
Blood clot in a vein usually leg vein did to prolonged inactivity.
17
Q
How did Meselson and Stahl’s classic experiment support the theory of semi-conservative DNA replication?
A
Two samples of bacteria were grown- one in a nutrient broth containing light nitrogen and one with heavy nitrogen. As bacteria reproduced they took up nitrogen to make the nucleotides so gradually nitrogen became a part of the DNA.They placed bacteria from the heavy broth in the light nitrogen broth and allowed one round of DNA replication.They then centrifuged it and found that the newly replicated DNA sat in the middle, suggesting its semi-conservative.
18
Q
How does ventilation detect and react to increased levels of CO2?
A
1- CO2 dissolves in the blood plasma making carbonic acid. 2- Carbonic acid dissociates into hydrogen ions and hydrogencarbonate ions thereby lowering the pH of the blood. 3- Chemoreceptors sensitive to hydrogen ions are located in the ventilation centre of the medulla oblongata. They detect the rise in hydrogen ion concentration. 4- Impulses are sent to other parts of the ventilation centre. 5- Impulses are sent from the ventilation centre to stimulate the muscles involved in breathing.
19
Q
Explain the blot clotting process
A
Thromboplastin is released from the damaged blood vesselThromboplastin triggers the conversion of prothrombin (a soluble protein) into thrombin (an enzyme).Thrombin catalyses fibrinogen (a soluble protein) into fibrin (insoluble fibres)Fibrin fibres form a mesh in which platelets and red blood cells get trapped
20
Q
What does the plasmid of a prokaryotic cell do and what is it made up of?
A
Plasmids are small loops of DNA and contain genes for things like anti-biotic resistance. They are not always present and some bacteria contain several.
21
Q
What is the definition for incomplete dominance?
A
When a trait for a dominant allele isn’t completely shown over the trait produced by the recessive allele, so both alleles influence the phenotype.
22
Q
Homeostasis
A
The maintenance of a stable internal environment.
23
Q
Where is the sinoatrial node (SAN) located?
A
wall of right atrium
24
Q
What social and ethical issues are as a result of prenatal testing?
A
Increases the risk of miscarriageFalse results could provide incorrect informationUnethical to abort?
25
Frontal lobe
Higher brain functioning: decision making, reasoning, planning and consciousness of emotions.
Sends information to the body via the motor neurones to carry out movements.
26
How does L-dopa help patients with Parkinson's?
L-Dopa is a drug that is used to treat the symptoms of Parkinson's disease.Its structure is very similar to dopamineWhen L-dopa is given its absorbed into the brain and converted into dopamine by the enzyme dopa-decarboxylase. This increases the level of dopamine in the brain.Higher level of dopamine means that more nerve impulses are transmitted across the synapse in the parts of the brain that control movement.This gives sufferers of Parkinson's more control over their movements.
27
How does diet impact your likelihood to develop CVD?
A diet high in saturated fat increases the risk of CVD. This is because it increases blood cholesterol levels, which increases atheroma formation. Atheroma's can lead to the formation of blood clots.
A diet high in salt increases the risk of CVD as it increases the risk of high blood pressure.
28
How do the rough ER and Golgi apparatus help in the formation of extracellular enzymes?
The extracellular enzymes are modified in the vesicles and then are transported around the cell and then moved to the cell and secreted.
29
What are 5 features of hormonal control in animals?
Chemical transmission through the bloodSlower actingCan control long-term changes eg growthBlood carries the hormone to all cells but only target cells are able to respondResponse may be widespread, such as growth and development.
30
What happens during the critical period so that mammals can develop their visual capacities to the full?
At birth there is overlap between the territories of the different axons. Axons compete for target cells in the visual cortex. Every time a neurone fires onto a target cell, the synapse of another neurone sharing the target cell is weakened and they release less neurotransmitters. If this happens repeatedly they will be cut back.
31
What are statins? Give a benefit and a risk
Reduce blood cholesterol. Which reduces atheroma formation.
+Reduce risk of CVD
-Muscle and joint pain, digestive problems and increased risk of diabetes.
32
How do steroid cells affect cells?
The hormone is formed from lipids and have complex ring structures.They pass through the cell membrane and bind directly to the receptor molecule within the cytoplasm.Once activated the hormone-receptor complex which acts as a transcription factor.A transcription factor turns enzyme synthesis on or off.
33
What is prenatal testing?
Screening unborn babies for genetic disorders.
34
Draw and describe Temporal summation
Several impulses arrive at a synapse having travelled along a single neurone one after the other. Their combined release of neurotransmitter generates an action potential in the postsynaptic membrane.
35
Stimulation the sympathetic nerve causes heat rate to?
increase
36
How does gender impact your likelihood to develop CVD?
More common in men due to hormones such as oestrogen as it increases the levels of HDLs in the blood.
37
How are genes switched on by transcription factors?
RNA polymerase is present and if all required transcription factors are present eg hormones. RNA polymerase and the transcription factors are present and bind to the promoter region which is adjacent to the gene to be transcribed.This forms the transcription initiation complex and transcription will proceed.
38
What effect does adrenaline have on heart rate?
Similar to stimulation of sympathetic nerve. But directly effects the sinoatrial node increasing the heart rate to prepare the body for physical demands.
39
What is the function of the nucleolus?
The nucleolus makes ribosomes
40
Describe the key features of nervous control
electrical transmission by nerve impulses and chemical transmission at synapse.fast actingusually associated with short term changes eg muscle contraction.action potential carried by neurones with connections to specific cells.response is often very local, such as specific muscle cell or gland.
41
What is indoleacetic acid (IAA)?
an auxin
42
What does the cardiovascular control centre detect?
Carbon dioxide and lactate accumulation in the blood, reduction of oxygen and increased temperature.
43
Give 1 reason why CVS is a better than amniocentesis and 1 reason why its not
Better- Takes place earlier so earlier decision to abort can be made.
Worse- 1-2% chance of miscarriage compared to 1% of amniocentesis.
44
What effect did IAA and illumination have on plants?
Its role is to stimulate growth and its response is cell elongation.They found that more auxin had passed down the shaded side of the plant when it was illuminated from one side.The reduced concentration on the illuminated side inhibited cell elongation.
45
What is the function of the mitochondrion?
The site of the aerobic respiration, where ATP is produced. They're found in large numbers in cells that are very active and require lots of energy.
46
Draw and describe Spatial summation
Impulses from different synapses, usually from different neurones. The number of different sensory cells stimulated can be reflected in the control of the response.
47
What does a lysosome do?
Contains digestive enzymes. These are kept separate from the cytoplasm by the surrounding membrane and can be used to digest invading cells or to breakdown worn out components of the cell.
48
What happens to the skin when it is warm?
Vasodilation
The shunt vessel constricts and muscles in the walls of the arterioles relax.Blood flows through the arterioles making them dilate. More blood flows closer to the surface.More energy is lost.
49
What is the structure of a strand of DNA and RNA?
polynucleotides composed of mononucleotides linked through condensation reactions.
50
Why are key hole surgeries helpful to those wanting to participate in sport?
As only a small incision is made the recovery is faster, and it is not uncommon for top athletes to return to normal athletic activities within a few weeks.
51
What does the capsule of a prokaryotic cell do and what is it made up of?
Made up of secreted slime it helps to protect the bacteria from attack by cells of the immune system.
52
Which are the first ventricular cells to be depolarised and why?
The ventricular cells at the apex of the heart so the contractions travel upwards.
53
What are the disadvantages of exercising too little?
Increased risk of obesity, cardiovascular disease (CVD) and diabetes
54
What is the function of the nucleus
Controls the cells activities (by controlling the transcription of DNA) DNA contains instructions to make proteins. The pores allow substances to move between the nucleus and the cytoplasm.
55
What is the function of the Golgi apparatus?
It processes and packages new lipids and proteins. It also makes lysosomes.
56
How can genes be prevented from being transcribed
Protein repressor molecules that bind to DNA of the promoter regionProtein repressor molecules can bind to the transcription factors themselvesThe repressor molecules could be inactive forms of the transcription factors
57
What bonds holds the bases of the polynucleotides together?
Hydrogen bonds
58
What are the two nerves connecting the cardiovascular control centre to the heart?
sympathetic nerve and vagus nerve.
59
How do peptide hormones affect cells?
Peptide hormones are protein chains which are not able to pass through cell membranes easily as they are charged.So instead they bind to a receptor on the cell membrane. This then activates another molecule within the membrane ‘the second messenger’ which brings about chemical changes in the cell.
60
Why is the arrangement of the DNA double helix the way it is?
The hydrophilic phosphate groups are on the outside of the molecule and the hydrophobic bases lie within the molecule.
61
What happens to the impulse generated from the SAN?
\* The impulse spreads across the right and left atria causing them to contract at the same time.
\* The impulse also spreads to the atrioventricular node
\* From here the impulse is conducted to the ventricles after about 0.13 second delay.
62
What are platelet inhibitory drugs? Give a benefit and a risk
Type of anticoagulant, prevent platelets clumping together.
+Treat people who already have blood clots
-Rashes, diarrhoea and excessive bleeding.
63
How does smoking impact your likelihood to develop CVD?
Carbon monoxide combines with haemoglobin and reduces the amount of oxygen transported in the blood. This reduces the amount of oxygen available to the tissues. If the heart muscles don't receive enough oxygen it can lead to a stroke.Nicotine in cigarettes makes platelets sticky increasing the chance of blood clots forming.Decreases the amount of antioxidants in the blood, these are important in protecting cells from damage. Fewer antioxidants means cell damage in the artery is more likely.
64
How is the egg cell specialised for its function?
Follicle cells- form protective coatingZona pellucida- protective glycoprotein layer that sperm have to penetrate.
65
What are the complementary base pairs in DNA?
A and T, and C and G
66
What happens when a nerve is stimulated?
If a threshold level due to stimulus is met the voltage dependant Na+ channels open. Na+ flows into axon depolarising the membrane.Voltage dependant Na+ channels close. Voltage dependant K+ channels open. K+ leave the axon repolarising the membrane.The membrane is hyperpolarised. The voltage dependant K+ channels close. K+ diffuse back into the axon to recreate the resting potential.
67
Occipital lobe
Processing information from the eyes, including vision, colour, shape, recognition and perspective.
68
How does cell expansion as a result of auxins occur?
The auxins cause the acidification of the cell wall by stimulating the activity of proton pumps that move H+ ions out of the cytoplasm and into the cell wall.The low pH in the cell wall disrupts the bonds that hold the cellulose microfibrils and hemicelluloses together.There is loosening of the cell wall: there is slippage of the polysaccharides relative to each other, bond reform in new locations, allowing bonds to reform in new locations.
69
What does the flagellum of a prokaryotic cell do and what is it made up of?
Long hair like structure that rotates to make the prokaryotic cell move. Not all prokaryotes have a flagellum. Some have more than one.
70
What are the 4 lobes of the brain?
Frontal lobeParietal lobeOccipital lobeTemporal lobe
71
Describe the process of translation of DNA
mRNA attaches to a ribosome and tRNA molecules carry amino acids to the ribosome.A tRNA molecule with an anticodon that's complementary to the start codon on the mRNA attaches itself to the mRNA by complementary base pairing.A second tRNA molecule attaches itself to the next codon on the mRNA in the same way.The two amino acids attached to the tRNA molecule are then joined together by a peptide bond. The first tRNA molecule moves away, leaving its amino acid behind.The ribosome moves along to the next codon.A third tRNA molecule binds to that codon on the mRNA. Its amino acid binds to the first two and the second tRNA molecule moves away.This process continues, producing a chain of linked amino acids (a polypeptide chain) until there's a stop codon on the mRNA molecule.The polypeptide chain moves away from the ribosome and translation is complete.
72
What is the description of the nucleus?
A large organelle surrounded by a nuclear envelope which contains many pores. The nucleus contains chromatin (made from DNA and proteins) and the nucleolus.
73
Describe the process of how normal lungs regulate mucus water content when there is too little water in the lungs
\* Cl- is pumped into the cell across the basal membrane.
\* Cl- diffuses through the open CFTR channels.
\* Na+ diffuses down the electrical gradient into the mucus.
\* Elevated salt concentration in the mucus draws water out of the cell by osmosis.
\* Water is drawn into the cell by osmosis.
74
What is the rough endoplasmic reticulum
A system of membranes enclosing a fluid filled space. The surface is covered with ribosomes.
75
How do Inhibitory synapses work?
They make it less likely that an action potential will result in the post synaptic cell.
Chloride ions move into the cell carrying a negative charge and potassium ions will move out carrying a positive charge. The result will be greater potential difference across the membrane as the inside becomes more negative than usual (hyperpolarisation). Making subsequent depolarisation less likely. More excitatory synapses will be required to depolarise the membrane.
76
What are the 4 ethics frameworks
Right and duties max amount of good in world making decisions by self leading a virtuous life
77
Where are ribosomes found?
Free in the cytoplasm or attached to the endoplasmic reticulum.
78
how do you calculate cardiac output?
stroke volume x heart rate
79
What week of pregnancy is CVS tested?
11-14 weeks
80
Cones
Allow colour vision in bright light but don't work in dim light.
81
What week of pregnancy is amniocentesis tested?
15-20 weeks
82
How does a synapse transmit an impulse?
An action potential arrivesThe membrane depolarises. Ca+ channels open. Ca+ enter the neurone.Ca+ cause the synaptic vesicle containing neurotransmitter to fuse with the presynaptic membraneNeurotransmitter is released into the synaptic cleftNeurotransmitters bind with receptors on the post synaptic membrane. Cation channels open. Na+ flow through the channels.The membrane depolarises and initiates an action potential.When released from the receptor the neurotransmitter will be taken up across the presynaptic membrane (whole or broken down) or it can diffuse away and be broken down.
83
How do genetics impact your likelihood to develop CVD?
Some people inherit particular alleles that make them more likely to have high blood pressure or high blood cholesterol.
84
How is habituation achieved?
With repeated stimulation the Ca2+ channels become less responsive so less Ca2+ crosses the presynaptic membrane.Less neurotransmitter is releasedThere is less depolarisation of the postsynaptic membrane so no action potential is triggered in the motor neurone.
85
Explain the course of events that lead to atherosclerosis
Endothelial disfunction where the endothelium becomes damaged.Inflammatory response occurs where white blood cells move to the damaged area.Plaque formation where white blood cells, lipids and connective tissues form an atheroma.This causes positive feedback as blood pressure rises.
86
Draw a sensory neurone
\* Dendrites
\* Axon
\* Terminal branches
\* Cell body external in between Schwann cells
87
Where is the hypothalamus?
It lies below the thalamus
88
Why does vigorous exercise supress the immune system?
The specific immune system is temporarily depressed.
89
How many hydrogen bonds does A and T have?
2 hydrogen bonds
90
Draw a Motor neurone
\* Dendrites around cell body which is at end of cell
\* Axon
\* Terminal branches at end
\*
91
What is stroke volume?
the volume of blood pumped out of the left ventricle each time the ventricle contracts
92
What are antihypertensives? Give a benefit and a risk
Reduces blood pressure.
+Patients can be treated at home
-Can cause abnormal heart rhythms, fainting and headaches
93
What happens to the skin in order to preserve heat?
Vasoconstriction
The muscles in the arteriole walls contract causing arterioles to constrict.Reducing the blood supply to the surface capillaries. Blood is diverted through the shunt vessel which dilates as more blood flows through it.Blood flows further from the skin so less energy is lost.
94
How do blood clots cause CVD?
When a coronary artery becomes completely blocked by a blood clot an area of the heart muscle will be completely cut off from its blood supply, so it wont receive any oxygen and wont be able to carry out respiration.
95
Describe the route of nerve impulses
Receptors detect a stimulus and generate a nerve impulse.Sensory neurones conduct a nerve impulse to the CNS along a sensory pathway.Sensory neurones enter the spinal cord through the dorsal route.Sensory neurone forms a synapse with a relay neurone.Relay neurone forms a synapse with a motor neurone that leaves the spinal cord through the ventral route.Motor neurone carries impulses to an effector which produces a response.
96
Explain the route taken by by electrical impulses?
\* Electrical impulses from the SAN spread across the atria walls causing contractions.
\* Impulses pass to the ventricles via the AVN
\* Impulses pass down the Purkyne fibres to the heart apex.
\* The impulses spread upwards through the ventricle walls causing contractions from the apex upwards. Blood is squeezed into the arteries.
97
Where is the medulla oblongata?
Just above the spinal cord
98
Phytochromes
They absorb red and far-red light. Red light triggers germination and far-red inhibits.
99
What happens to rod cells in the dark?
Na+ diffuse in through open cation channels Na+ move down concentration gradientNa+ actively pumped out causing membrane to be slightly depolarised -40mV triggering neurotransmitter (glutamate) release.Inhibitory synapse, neurotransmitter released binds to bipolar cell, preventing it depolarising.
100
Stimulation the vagus nerve causes heat rate to?
slow down
101
How do electrocardiograms (ECG) work?
Electrodes are attached to a persons chest and limbs to record the electrical current produced during the cardiac cycle.
102
How does high blood pressure impact your likelihood to develop CVD?
Increases the risk of damage to artery walls, which increases the risk of atheroma formation, which can lead to CVD.
Excessive alcohol, stress and diet can all increase blood pressure.
103
What is the definition for genotype
The alleles a person has eg BB, Bb or bb
104
What are the two types of nerves in the autonomic nervous system?
sympathetic and parasympathetic
105
Where is the cerebellum?
below the temporal and occipital lobe.
106
Describe the process of DNA replication
Enzyme DNA helicase breaks the hydrogen bonds between bases on the two polynucleotide strands. This makes the helix unwind to form two single strands.Each original single strand acts as a template for a new strand. Complementary base pairing means that free floating DNA nucleotides are attracted to their complementary exposed bases on each original template strand.Condensation reaction join the nucleotides of the new strands together- catalysed by the enzyme DNA polymerase. Hydrogen bonds form between the bases on the original and new strands.Each new DNA molecule contains one strand from the original DNA molecule and one new strand.
107
How is the resting potential maintained?
Na+/K+ pump creates a concentration gradient across the membrane.K+ diffuse out of the cell down the K+ concentration gradient, making the outside of the membrane positive and the inside negative creating a potential difference.The potential difference will pull K+ back into the cellAt -70mV potential difference, the two gradients counteract each other and there is no net movement of K+ ions.
108
What is the definition for an allele
A different version version of a gene
109
CT scans
Uses radiation but less than x-raysGive a frozen moment pictureLook at structures rather than functionsLimited resolution so small structures cannot be distinguished.
110
Why is it important that the impulse at the atrioventricular node is delayed?
The delay ensures that the atria have finished contracting and the ventricles have filled with blood before they contract.
111
What was Hubel and Wiesel's study on monkeys about?
The monkey's were deprived of light in one eye for 6 months. Monocular deprivation. After 6 months the eye was exposed to light. The monkey was blind in the light deprived eye. Retinal cells did respond, but the cells in the visual cortex did not.
Deprivation in adult monkeys had no effect. Visual deprivation in both eyes had much less effect than just one.
112
What is the function of the ribosome?
The site where proteins are made.
113
What are ribosomes composed of?
2 subunits: a smaller and larger subunit. The larger subunit contains two tRNA binding sites and the mRNA attaches to the smaller subunit.
114
How does the CF mutation impact the reproductive system in females?
Mucus develops in the cervix stopping sperm from reaching the egg
115
What is a gene?
A sequence of bases on a DNA molecule that code for a sequence of amino acids on a polypeptide chain.
116
What is the impact of a mutation?
The order of DNA bases in a gene determines the order of amino acids in a particular protein. If a mutation in a gene, the primary structure (the sequence of amino acids) could be altered. Which could change the final 3D shape of the protein so it doesn't work properly.
117
Why is the charge inside of the membrane of a neurone more negative than the outside?
As the inside of the membrane has a higher K+ concentration and a lower Na+ concentration. (Vice versa outside)
118
Where is the temporal lobe
By the ears
119
Temporal lobe
Auditory information: hearing, sound recognition and speech. Also memory.
120
What is the nature of the genetic code?
Triplet code- each adjacent group of 3 bases codes for an amino acid.
Non-overlapping- each triplet code is adjacent.
Degenerate- Several triplets can code for the same amino acid.
121
What are the bundles of fibres around the ventricles called?
bundle of His
122
What are the 4 methods of energy transfer?
RadiationConductionConvectionEvaporation
123
Explain the process in which proteins are transported in cells?
Proteins are made at the ribosomes on the rough ER.New proteins produced at the rough ER are folded and processed in the rough ER.The proteins are then transported from the ER to the Golgi apparatus in vesicles.At the Golgi apparatus, the proteins may undergo further processing (further modification)The proteins enter more vesicles to be transported around the cell.
124
What does the heat gain centre stimulate or inhibit?
Stimulates
\* Arterioles in the skin to constrict
\* Hair erector muscles to contract
\* Liver to raise metabolic rate
\* Skeletal muscles to contract in shiveringInhibits
\* Sweat glands
125
Rhodopsin
A purplish photochemical pigment that absorbs the light in rod cells resulting in a chemical changes.
126
What is the mitochondrion?
They're usually oval-shaped. They have a double membrane- the inner one is folded to form structures called cristae. Inside the matrix, which contains enzymes involved in respiration.
127
What part of the brain contains the cardiovascular control centre?
medulla oblongata
128
What is the structure of A and G?
They have a 2 ring structure
129
What does the pili of a prokaryotic cell do and what is it made up of?
Pili help prokaryotes stick to other cells and can be used in the transfer of genetic material between cells.
130
What is acetylcholine?
a neurotransmitter
131
How does the amount of blood ejected change during exercise?
When the body is at rest normally 40% of the blood remains in the ventricles but during exercise stronger contractions occur ejecting more of the residual blood from the heart.
132
What is the structure of C and T
They have 1 ring
133
What are the social and ethical issues of carrier testing?
May cause emotional stress if you're a carrier.Tests aren't 100% accurateCould result in genetic discrimination by employers or life insurance companies.
134
Explain the process of temperature control through negative feedback
Set point Temperature rise/fall is detected by receptorsSends impulse to heat loss heat gain centre in hypothalamusEffector reactsTemperature falls/risesSet point
135
fMRI scans
Provides information about brain in action.Can study memory, emotion, language and consciousness.Places with higher oxygen consumption have higher activity levels
136
Why are the 3 reasons CF lungs not regulate the water in mucus?
CFTR channel is absent or not functional.Na+ channel is permanently open.Water is continually removed from mucus by osmosis.
137
Principle of negative feedback
Maintaining systems within narrow limits
138
What are prokaryotic cells
They are smaller and simpler eg bacteria
139
What are the main symptoms of Parkinson's?
Stiffness of musclesTremor of the musclesSlowness of movementPoor balanceWalking problems
140
Why is the axons resting potential -70mV?
Potassium ions diffuse out of the cell due to the concentration gradient. The more potassium ions that diffuse out of the cell the larger the potential difference across the membrane.The increased negative charge inside the cell attracts potassium ions back across the membrane into the cell.When the potential difference across the membrane is -70mV, the electrical gradient exactly balances the chemical gradient. So there is no net movement of K+ which maintains the potential difference.
141
How does the CF mutation impact the reproductive system in males?
The sperm duct wont be there or is blocked
142
What is the definition for phenotype
The characteristics displayed by an organism eg brown eyes
143
What is the refractory period and how long does it last?
The period when new action potential cannot be generated in the same section of membrane for about 5 milliseconds.
It lasts until all the voltage dependent sodium and potassium channels have returned to their normal resting state and the resting potential is restored.
144
Parietal lobe
Orientation, movement, sensation, calculation and some types of recognition and memory
145
What does the heat loss centre in the hypothalamus stimulate and inhibit?
Stimulates
\* Sweat glands to secrete sweat.Inhibits
\* Contraction of arterioles in skin (dilates capillaries in skin)
\* Hair erector muscles (relax- hairs lie flat)
\* Liver (reduces metabolic rate)
\* Skeletal muscles (relax- no shivering)
146
What are the homeostatic control mechanisms trying to return to?
Norm value or set point
147
What are the two types of prenatal testing?
Amniocentesis and Choronic Villus Sampling
148
How many hydrogen bonds do C and G have?
3 hydrogen bonds
149
What are 5 features of nervous control in animals?
Electrical transmissions by nerve impulses and chemical transmission at synapsesFast actingusually associated with short term changes eg muscle contractionAction potential carried by neurones with connections to specific cellsResponse is often very local such as a specific muscle cell or gland
150
What is a ribosome?
A very small organelle that either floats free in the cytoplasm or is attached to the rough endoplasmic reticulum. Its made up of proteins and RNA. Its not surrounded by a membrane.
151
What is the smooth ER?
A system of membranes enclosing a fluid filled space but has no ribosomes.
152
ventilation
movement of air in and out of the lungs
153
What bond holds together adjoining nucleotides via the sugar (ribose or deoxyribose) and the phosphate?
phosphodiester bonds
154
Positive feedback
Feedback that tends to magnify a process or increase its output.
155
What are cardiac muscles and what does it mean?
Myogenic: means they can contract without external nervous stimulation
156
What does a mononucleotide look like?
157
What is the golgi apparatus?
A group of fluid filled membrane bound, flattened sacs. Vesicles are often seen at the edges of the sacs.
158
Function of Relay neurones
Connect neurones
159
What does the smooth ER do?
Synthesises and processes lipids.
160
Describe the key features of hormonal control
chemical transmission through the blood slower actingcan control long term changes eg growthblood carries the hormone to all cells but only target cells are able to respondresponse may be widespread, such as in growth and development.
161
What is the basic structure of mononucleotides?
Deoxyribose or ribose linked to a phosphate and a base, including thymine, uracil, cytosine, adenine or guanine.
162
What is saltatory conduction?
When the impulse jumps from one node to the next due to myelination of the membrane increasing the speed of conduction.
163
What is the function of the cerebellum?
Maintenance of balance and posture
164
What kind of proteins are made at the rough ER? vs in free floating ribosomes in the cytoplasm?
Rough ER- Proteins that are excreted or attached to the cell membrane
Free ribosomes- make proteins that stay in the cytoplasm
165
How does inactivity impact your likelihood to develop CVD?
Lack of exercise increases the risk of CVD because it increases blood pressure.
166
Why are hairs raised when it is cold?
As hair erector muscles contractIn the aim to trap a layer of air that insulates our body.
167
Rods
Rods only give black and white vision but work in dim light as well as bright light.
168
What are eukaryotic cells?
They are complex and include all animal and plant cells.
169
How do surgeons carry out an arthroscopic procedure?
They make one or two small incisions, often only 4mm long. A small camera and light source are inserted, allowing the inside of the joint to be seen and a diagnosis can be made or confirmed. Then if surgery is required, miniature instruments are inserted through the incisions.
170
What does serotonin do?
Serotonin transmits nerve impulses across the synapse in the parts of the brain that control mood.
171
How does CF impact the gaseous system?
Cilia are unable to move the mucus towards the throat because its so thick and sticky.This means mucus builds up in the airways.Some airways can become completely blocked by the mucus- gas exchange cant take place in the area below the blockage.This means the surface area available for gas exchange is reduced, causing breathing difficulties.People with CF are also more prone to lung infections as mucus containing microorganisms cant be removed.
172
What is CF?
A mutation in the gene that codes for the CFTR protein.
173
Explain the process of fertilisation in mammals
Sperm swims towards the egg cell in the oviduct.Once one sperm makes contact with the zona pellucida of the egg cell and the acrosome reaction occurs. Digestive enzymes are released from the acrosome of the sperm.These enzymes digest the zona pellucida, so the sperm can move through it to the cell membrane of the egg cell.The sperm head fuses with the cell membrane of the egg cell.Triggering a cortical reaction where the egg cell releases cortical granules to make the zona pellucida thicken, which makes it impenetrable to the other sperm.Only the sperm nucleus enters the egg cell the tail is discarded.The nucleus of the sperm fuses with the nucleus of the egg cell.
174
What is a prokaryotic cell made up of?
Cell wallCapsulePlasmidFlagellumPiliRibosomesMesosomesCircular DNA
175
What is the function of the medulla oblongata?
Transmitting signals between the spinal cord and the higher parts of the brain and in controlling autonomic activities, such as heartbeat and respiration.
176
What happens to rod cells in the light
Rhodopsin absorbs light and breaks down into retinal and opsin. Opsin activates a cascade of reactions that result in the closing of the non specific cation channels.As the cation channels have closed no Na+ can enter.Na+ actively pumped out causing membrane to e hyperpolarised.No neurotransmitter is released No inhibition so cation channels in bipolar membrane open and membrane becomes depolarised. Generating an action potential which is transmitted to the neurone of the optic nerve.
177
Where is the frontal lobe?
Front of head
178
Where is the occipital lobe?
Back of head
179
Role of Schwann cells
To speed up the rate of transmission
180
Describe the process of transcription?
\* RNA polymerase attaches to the DNA and hydrogen bonds between the pairs break and the DNA molecule unwinds.
\* The sequence of the template strand is transcribed to make an mRNA molecule with the same base sequence as the DNA coding strand.
\* The complementary RNA nucleotides align themselves into position and phosphodiester bonds form to produce an mRNA molecule.
\* The mRNA molecule leaves the nucleus through a pore in the nuclear envelope.
181
Describe how an impulse travels along a membrane.
At resting potential there is a positive charge on the outside of the membrane and negative change on the inside, with high sodium ion concentration outside and high potassium ion concentration inside (membrane No.1).
When stimulated, voltage dependant sodium ion channels open. Sodium ions flow into the axon depolarising the membrane.
Sodium ions move to the adjacent polarised (resting) region (membrane No.2) causing a change in the electrical charge (PD) in this part of the membrane (membrane No.2).
The change in the potential difference in (membrane No.2) initiates a second action potential in (membrane No.3).
In (membrane No.1) the voltage dependant sodium ion channels close and the voltage dependant potassium ion channels open. Potassium ions leave the axon repolarising the membrane and the membrane becomes hyperpolarised.
A third action potential (in membrane No.3) is initiated by the second (in membrane No.2). The local electrical currents cause the nerve impulse to move along the axon. (In membrane No.1) potassium ions diffuse back into the axon, restoring the resting potential.
182
Argue why performance enhancing drugs should be able to be used
It is the athletes decision if they choose to take the drugs. That the sport is already unfair due to the inequality of competition due to the differences in time available for training and in resources
183
What is the centriole?
Small, hollow cylinders made of microtubules (tiny protein cylinders) Found in animals, but only some plant.
184
What are the 3 uses of genetic screening?
\* Identification of carriers
\* Preimplantation genetic diagnosis
\* Prenatal testing
185
What is the resting potential for an axon? (what is the charge of the inside of the axon compared the the outside)
-70mV
186
When we get too hot which centre is activated?
The heat loss centre in the hypothalamus
187
Opsin
When rhodopsin absorbs light and breaks down into retinal and opsin. Opsin activates a cascade of reactions that result in the closing of the non-specific cation channels.
188
Argue why performance enhancing drugs should not be used
Performance enhancing drugs are bad for the athletes health and they might not make a properly informed decision to take the drugs. They may be pressured by coaches, sponsors and general public.
189
What is meant by pluripotency?
The ability for a stem cell to produce all the specialised cells in an organism but not extraembryonic cells.
190
How do auxins cause changes such as cell expansion, division and differentiation?
The auxins bind to protein receptors in the target cells.This activates intracellular second messenger signal molecules, which activate transcription factors.These control the transcription of auxin-regulated genes and proteins produced bring about metabolic changes These metabolic changes result in responses such as cell expansion, division and differentiation.
191
Give 2 reasons why animals should not be used in medical research?
Humans consent and as animals cannot consent they shouldn't be used in trialsIt is harmful to the animal, and no vertebrates should be used when there are non-animal alternatives
192
What is the template strand also known as?
The antisense strand
193
What causes Parkinson's?
Dopamine secreting neurones in the basal ganglia die. These neurones normally release dopamine in the motor cortex.
Fewer sodium ion channels on the post synaptic membrane open, so the post synaptic cell is less likely to be depolarised. This means fewer action potentials are produced leading to symptoms such as tremors.
194
What ligaments can be very effectively tackled by a key hole surgery?
Cruciate ligaments
195
venous return
The amount of blood returned to the heart by the veins
196
What are anticoagulants? Give a benefit and a risk
Reduce blood clotting. This means blood clots are less likely to form at sites of damage and block arteries.
+Treat those who already have CVD as they prevent new blood clots forming or prevent others growing larger.
-If a person is badly injured, reduction in blood clotting can cause excessive bleeding.
197
What does ‘translation’ mean in terms of biology?
Turning the sequence of bases in the genetic code into a sequence of amino acids.
198
What does the cell wall of a prokaryotic cell do and what is it made up of?
Supports the cell and prevents it from changing shape. Its made of a polymer called murein. Murein is a glycoprotein (a protein with a carbohydrate attached)
199
Where does depolarisation start?
sinoatrial node
200
Give 2 reasons why it is okay to use animals in medical research?
Can certain animals suffer, do they have the mental ability to suffer?Utilitarianism is the belief that the right course of action is the one that maximised the amount of overall happiness or pleasure in the world. That animals can be used so long as the overall expected benefits are greater than the overall expected harms.
201
What is the myelin sheath?
A fatty insulating layer around the axon
202
Why can't dopamine be given to treat parkinsons?
As dopamine cannot enter the brain.
203
Why do we sweat when our body temp is too high?
Sweat released on the skin evaporates Taking heat energy from the skin.Sweat glands are stimulated by nerves from the hypothalamus.
204
What is thymine replaced with in RNA?
Uracil
205
Function of motor neurone
Conducts impulses from CNS to effectors
206
What are the two nucleotide strands described as being?
Antiparallel as they run in opposite directions
207
What are the two ways memories are stored?
the pattern of connectionsthe strength of synapses
208
Homozygote
BB or bb
209
Understand how the … of multicellular organisms are organised into …., and …… into …… and …….. into ……..
Cells tissues tissues organs organs systems
210
Why is habituation important?
It gives animals the ability to ignore unimportant repetitive stimuli so that limited sensory , attention and memory resources can be concentrated on more threatening or rewarding stimuli.
211
Negative feedback
A change in a physiological variable that is being monitored triggers a response that counteracts the initial fluctuation.
212
How does CF mutation affect digestion in patients?
\* pancreatic duct is blocked by sticky mucus
\* Impair the release of digestive enzymes lowering the concentration of enzymes within the small intestine.
\* The mucus lining is also abnormally thick reducing the absorption of nutrients.
213
What is a lysosome?
A round organelle surrounded by a membrane, with no clear internal structure.
214
What are mutations?
Changes to the base sequence of DNA
215
What is meant by stem cell
unspecialised cells that develop into other types of cells.
216
What are the possible disadvantages of exercising too much?
Wear and tear on joints, suppression of the immune system.
217
Where is the parietal lobe?
Top of head
218
How does IAA bring about responses in plants?
Increased concentration on the shaded side of the plant causes cell elongation. The reduced concentration on the illuminated side inhibited cell elongation.
219
What causes depression?
Low levels of the neurotransmitter serotonin
220
What is the function of centrioles?
Involved with the separation of chromosomes during cell division.
221
What initiates the heart to contract?
Small changes in the electrical impulses and polarity causes the cells to contract.
222
What causes the pupil to dilate?
Radial muscles contract and the circular muscles relax
223
What is the sinoatrial node (SAN) known as?
pacemaker
224
What is the definition for recessive
An allele whose characteristic only appears in the phenotype if two copies are present.
225
What do the ribosomes of a prokaryotic cell do and what are they made up of?
They are smaller than in eukaryotic cell and make proteins.
226
What form is stroke volume calculated?
cm3
227
What is the definition for gene?
A sequence of bases on a DNA molecule that codes for a protein, which results in a characteristic.
228
Function of sensory neurones
Carry impulses from sensory cells to the CNS
229
What are the 4 types of channels in a cell surface membrane?
Na+ gated channelNa+/K+ pumpK+ channelK+ gated channel
230
What happens as a result of the CF mutation?
\* CFTR is a channel protein. It transports chloride ions out of the cell and into the mucus- this causes water to move into the mucus by osmosis, which makes mucus watery.
\* Mutant CFTR protein is much less efficient at transporting chloride ions our of the cell so less water moves out by osmosis. This makes the mucus of people with CF abnormally thick and sticky.
\* The thick and sticky mucus causes problems in the respiratory, digestive and reproductive systems.
231
What do mesosomes of a prokaryotic cell do and what are they made up of?
Mesosomes are inward folds in the plasma membrane. They are believed to be involved in cellular processes.
232
How do phytochromes switch processes on or off?
Exposure to light causes phytochrome molecules to change from one form to another, bringing about a change in shape. The phytochromes may bind to the protein or disrupt the binding of a protein complex. These signal proteins may act as transcription factors or activate transcription factors that bind to DNA.
233
Describe the process of how normal lungs regulate mucus water content when there is excess water in the lungs
Na+ is actively pumped across the basal membrane (membrane with tissue fluid).Na+ diffuses through a sodium channels in the apical membrane (membrane with mucus).Cl- diffuses down electrical gradient.Water is drawn out of cells by osmosis due to the high salt concentration in the tissue fluid.Water is drawn out of the mucus by osmosis.
234
What causes the pupil to constrict?
Radical muscles relax and the circular muscles contract
235
What are the advantages of genetic screening?
Reduces the change of having a baby with a genetic disorder. As only embryos without genetic disorders tested will be implanted.
236
Function of the thalamus
Contains the thermoregulatory centre. Which monitors core body temperature and skin temperature. Also returning the body temp to optimum temperature.
Also controls sleep, thirst and hunger.
Also secrets hormones and acts as an endocrine gland
237
What happens after the signal delay at the atrioventricular node?
The signal delay reaches the Purkyne fibres which are specialised muscle fibres. They conduct impulses rapidly to the apex of the ventricles.
238
Heterozygote
Bb
239
What types of errors can occur during DNA replication?
SubstitutionDeletionInsertionDuplicationInversion
