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Biology Topic 5 > Topic 8 > Flashcards

Topic 8 Flashcards

(118 cards)

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1
Q

What will an exposure to red light trigger

A

Germination

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2
Q

What will an exposure to far-red light inhibit

A

Germination

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3
Q

What happens when a plant absorbs red (natural) light

A

Phytochrome is converted from inactive Pr to active Pfr
In the dark, Pfr slowly converts back into Pr
If exposed to far red light, it will change back rapidly

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4
Q

Define long day plants

A

Only flower when day length exceeds a critical value
When uninterrupted darkness is less than 12hrs
Need high levels of Pfr

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5
Q

Define short day plants

A

Only flower when uninterrupted darkness is greater than 12hrs
Need low levels of Pfr, therefore more Pr

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6
Q

What else, other than germination, does exposure of phytochromes to light stimulate

A

Development of primary leaves
Leaf unrolling
Production of pigments

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7
Q

How is greening of the shoot promoted

A

Causes the phytochromes to change shape through a series of interactions with other signal proteins
They activate transcription factors which cause the synthesis of enzymes that control chlorophyll production in greening of the shoot

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8
Q

What are phytochromes

A

Photoreceptors

That absorb red or far red light

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9
Q

Define the central nervous system

A

Part of the nervous system that consists of the brain and spinal cord

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10
Q

Define autonomic nervous system

A

Nervous response from his part of the nervousness system are involuntary and involve the smooth muscle

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11
Q

Define sympathetic nervous system

A

Prepares the body for fight or flight

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12
Q

Define parasympathetic nervous system

A

Prepared the body for rest and digest

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13
Q

What is the resting potential

A

The inside of an axon is more negative than the outside, making the membrane polarised at -70mV
Due to an uneven distribution of ions across the cell surface membrane

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14
Q

How is the resting potential created within an axon

A

1) Na/K+ pumps create a concentration gradient across the membrane
2) k+ diffuse out of the cell down the conc gradient, making the outside of the membrane positive and the inside negative
3) electrical gradient will pull K+ back into the cell
4) at -70mV there is no net movement of K+ as the electrical gradient balances the chemical gradient

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15
Q

How is an action potential generated in an axon

A

1) voltage dependent gated Na+ channels open, allowing Na+ to flow into the axon, depolarising the membrane
2) the Na+ channels close whilst the voltage dependent gated K+ channels open, allowing K+ to leave the axon, repolarising the membrane
3) the membrane is hyperpolarised
4) the K+ channels close but K+ diffuse back into the axon through K+ channels to recreate the resting potential

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16
Q

What is the place two neurones meet at known as

A

A synapse

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17
Q

What is the neurotransmitter called used at a Cholinergic Synapse

A

AcetylCholine

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18
Q

What is the sequence of events at a synapse

A

1) an action potential arrives
2) the membrane depolarises allowing Ca2+ channels to open
3) the influx of Ca2+ causes synaptic vesicles to fuse with the presynaptic membrane
4) the neurotransmitter binds with receptors on the post-synaptic membrane causing Na+ channels to open
5) membrane depolarises and initiates an action potential

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19
Q

How is the neurotransmitter removed from the synaptic cleft

A

It is either broken down by enzymes

Or reabsorbed into the presynaptic neurone

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20
Q

Define excitatory synapse

A

Makes a membrane more permeable to sodium ions and therefore leads to depolarisation and an action potential

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21
Q

What are inhibitory synapses

A

They make it less likely for an action potential to be produced in the post synaptic neurone
The channels for chloride and potassium ions are opens in the post, causing it to become hyperpolarised

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22
Q

Define summation

A

Each action potential adds to the effect

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23
Q

What are the two types of summation

A

Spatial

Temporal

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24
Q

Define spatial summation

A

A single exciting synapse typically does not depolarise the post synaptic membrane to generate an action potential

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25
Define temporal summation
Several impulses arriving within a short time cause depolarisation via the release of neurotransmitter
26
What are the general structures of a neurone
``` Cell body containing a nucleus Dendrites Terminal branches Axon Schwann cells Node of ranvier ```
27
What is a myelinated neurone
Myelin is a layer of lipid produced by Schwann cells | It electrically insulated the neurone
28
What are the two antagonistic muscles contained within the iris
Circular and radial
29
What did circular and radial muscles in the iris do
Control the size of the iris under the influence of the autonomic nervous system
30
How do iris muscles react in high light intensities
1) Rods cause nerve impulse to pass along the optic nerve to a group of nerve cells in the brain 2) impulses sent along sympathetic motor neurone to circular muscles 3) circular muscles contract , causing pupils to constrict
31
How do iris muscles react in low light intensities
1) fewer impulses reach the coordinating centre in the brain 2) impulses are sent down the sympathetic motor neurone to radial muscles 3) radial muscles contract, causing pupils to dilate
32
What is photoperiodism
Plants flower and seeds germinate in response to changes in day length
33
What is phototropism
Tropisms are growth responses in plants where the direction of the growth response is determined by the direction of external stimulus
34
What is the response known as if a plant growths towards a stimulus
Positive
35
What is the effector for growth response in plants
Cell elongation
36
Where does cell elongation occur and how is it controlled
Just below the tip of the shoot | By the plant growth substance IAA (an auxin)
37
Define stimuli
Any changes that occur in an animals environment
38
What are the two main photoreceptors
Rods and cones
39
What conditions do rod cells work in
Black and white | Work in both low and high light intensities
40
What conditions do come cells work in
Colour | High light intensities
41
How does light stimulate photoreceptor cells
1) rhodopsin is broken down into retinal and Olson 2) Na+ channels close whilst Na+ is actively pumped out of the membrane 3) the membrane becomes hyperpolarised 4) no neurotransmitter is released 5) cation channels in the bipolar cell open and the membrane becomes depolarised,generating an action potential in the neurone of the optic nerve
42
How do photoreceptors cells function at resting state (in the dark)
1) Na+ diffuse in through open cation channels 2) Na+ move down the conc gradient 3) Na+ is actively pumped out of the membrane 4) the membrane slightly depolarises due to influx of Na+ 5) neurotransmitter, Glutamate, is released and binds to the. I polar cell, preventing it depolarising
43
What is the main section of the brain called and what is it comprised of
The cortex | Two cerebral hemispheres
44
What connects the two cerebral hemispheres of the brain and what is it made of
``` Corpus callosum White matter (axons) ```
45
What four regions is each hemisphere made up of
Frontal lobe, parietal lobe, occipital one and temporal lobe
46
What areas of the brain is responsible for the ability to learn
Cerebral hemispheres
47
What is the function of the frontal lobe
Decision making Planning Contains primary motor cortex
48
What is the function of the parietal lobe
Orientation, movement, calculation
49
What is the function of the occipital lobe
Visual cortex
50
What is the function of the temporal love
Processing auditory information
51
What is the function of the thalamus
Routing incoming sensory information to the brain
52
What is the function of the hypothalamus
Contains thermoregulatory centre Used in homeostasis Acts as an endocrine gland
53
What is the function of the hippocampus
Involved in laying down long term memory
54
What is the function of the basal ganglia
Responsible for selecting and initiating stored programmes of movement
55
What is the the function of the corpus callosum
Provides a connection between The cerebral hemispheres and the mid brain
56
What is the function of the cerebellum
Responsible for balance
57
What is the function of the midbrain
Relays information to cerebral hemispheres
58
What is the function of the medulla oblongata
Regulates heart rate
59
What are the main effects of a stroke
Brain damage may cause problems with speaking, reading and writing
60
Define neural plasticity
The potential of neurones to change in structure and function
61
What are CT Scans and how are they used
``` Computerised Axial Tomography Cannot be used for imaging soft tissues Limited resolution 2D X-Ray's harmful ```
62
What is MRI and how is it used
``` Magnetic resonance imaging Uses a magnetic field and radio waves 3D Higher resolution Not suitable for people it's pace makers ```
63
What is fMRI and how is it used
Function MRI Follows oxygen uptake to active areas of the brain Provided information about the brain in action
64
Is depth perception innate or learnt and how is it tested
Innate | Using a visual cliff
65
What is the carpenter world hypothesis
Those who live in a world dominated by straight lines and right angles tend to perceive depth cues differently than those who live in a circular environment
66
What does the muller-layer illusion show
That depth cues make us think an object is further away
67
How can stem cells be used to restore vision
Transplanted into the eye | Bind to original cornea cells and multiply
68
What allows us to interpret the depth of close objects
Objects less than 30m away depend on the presence of cells in the visual cortex that obtain information from both eyes at once
69
What allows us to interpret the depth of distant objects
Objects more than 30m use visual cues and past experiences to interpret images
70
Why is it important to study new born babies when studying visual development
Babies are born short sighted | Babies are born with characteristic behaviours
71
What is a visual cliff
Babies are encouraged to crawl across a table made of glass or Perspex which acts as a visual cliff Patterns are placed brown the glass to create the appearance of a steep drop
72
How do axons grow
Neurones grow from the retina to the thalamus
73
What is the visual cortex comprised of
Comprised of columns of cells Adjacent columns receive stimulation from same area of the retina Map of retina created within visual cortex
74
What is the critical window
Period of time during postnatal development identified as being when the nervous system must obtain specific experiences to develop properly
75
What structures does visual stimulation create or strengthen
Strengthens synapses and stimulates axon growth
76
What happens to unused synapses
They are lost and cannot be reformed
77
What is the evidence for critical Windows
Hubel & Weisel (kittens) | Monocular deprivation
78
What happens during the critical window when further visual development occurs
Dendrites and synapses from the light-stimulated eye take up more territory in the visual cortex Axons then compete for target cells in the visual cortex
79
What happens during habituation
1) with repeated stimulus the Ca2+ channels in the presynaptic neurones become less responsive to the changes in voltage associated with action potentials 2) fewer Ca2+ ions enter the presynaptic neurone 3) less neurotransmitter is released 4) fewer Na+ channels are opened in the postsynaptic neurone, so there is less depolarisation of the membrane 5) an action potential is not generated in the post synaptic membrane 6) the Gill muscle does not contract and the Gill is not withdrawn
80
Define pure research
Basic investigation into aspects of biochemistry, physiology and anatomy
81
Define basic research
Done simply to gain knowledge
82
Define applied research
Done with intent to use the results practically
83
What percentage if any aka used in research are rats, mice and other rodents
85%
84
What are the alternatives to animal testing
In vitro techniques In silico techniques Epidemiology
85
How do characteristics form under nature
Develop solely under the influence of genes with little influence from our environment or learning
86
How do characteristics develop under Nature
Characteristics are learnt or are heavily influenced by the environment
87
How is neurotransmitter removed from the synaptic cleft
Neurotransmitter either broken down enzymes or reabsorbed into the presynaptic neurone Transporters in the presynaptic membrane take up the neurotransmitter serotonin from the synapse The neurotransmitter is then repackaged into synaptic vesicles
88
what effect does ecstasy have on serotonin
It blocks transporter proteins preventing re-uptake of serotonin The concentration of ecstasy in synapses will increase It continually stimulates the pleasure pathways of the brain
89
How does little dopamine contribute to Parkinson's Disease
The axons of neurones located in the basal ganglia which secrete dopamine into the motor cortex die
90
what are 3 symptoms of Parkinson's
stiffness of muscles tremor of muscles poor balance
91
List the methods of treatment for Parkinson's
``` Selegiline L-Dopa Agonists Gene therapy Cell therapy Surgical Techniques ```
92
What is Selegiline and how does it help treat Parkinson's
it slows the loss of dopamine from the brain by inhibiting the enzyme monoamine oxidase which breaks down dopamine in the brain
93
what is L-Dopa and how does it help treat Parkinson's
dopamine cannot be taken up from the blood stream directly | L-Dopa is converted into Dopamine in the brain
94
What does ecstasy do
It blocks transporter proteins preventing reuptake of the neurotransmitter serotonin When ecstasy is present, the conc of serotonin will increase in the synapses It contralto stimulate the pleasure pathways of the brain through increasing serotonin levels
95
What are Agonists and how can they help treat Parkinson's
drugs that activate the dopamine receptor directly, mimicking the role of dopamine
96
How can gene therapy be used to treat Parkinson's
uses genes that code for proteins that increase dopamine production and that promote the growth and survival of nerve cells are inserted into the brain
97
How can cell therapy be used to treat Parkinson's
proteins themselves which increase dopamine production are injected into the brain
98
How can surgical techniques be used to treat Parkinson's
Deep Brain Stimulation treats Parkinson's symptoms by implanting electrodes into areas of the brain
99
What is depression
a multifactoral disease linked to low serotonin levels
100
How is depression treated
drugs used to inhibit the re uptake of serotonin from synaptic clefts - Selective Serotonin Re-uptake Inhibitors Prozac maintains higher levels of Serotonin
101
Define genome
all the DNA of an organism
102
Define Single-Nucleotide Polymorphisms
DNA sequence variation that involves a change in a single nucelotide
103
What is junk DNA
non-coding sequences which make up 50% of the human genome
104
What is the Genetic Information Non-Discrimination Act 2003
prohibits the use of genetic information by insurers or employees
105
What is a candidate gene
a gene that may cause a particular disease
106
What is a drug target
specific molecule that a drug interacts with to bring about its effect
107
How is it hoped that the human genome project will improve preventative medicine and drug treatment
May help doctors to prescribe the correct drug | Allows for changes in lifestyle
108
What are 3 ethical issues associated with the Human Genome Project
Should insurers have access to the information? Confidentiality issues Discrimination in employment
109
How are bacteria genetically modified to produce insulin
1) the desired gene is located and isolated 2) insulin is inserted into a bacterial plasmid 3) reinsert the plasmid into a bacterium 4) culture the bacteria to cause them to asexually produce
110
How are micro-organisms genetically modified
1) restriction enzymes are used to cut the plasmids at a specific DNA sequence and the gene of interest from chromosomes 2) the gene is amplified using PCR with DNA Polymerase 3) Ligation of the transgene and the plasmid occurs with the enzyme ligase 4) plasmid is inserted back into the bacteria 5) bacteria multiply in a fermenter
111
how are plants genetically modified
GM crops have the potential to mass produce medicines and chemicals cheaply and efficiently Known as Micropropagation - cultured in agar
112
What are the methods used to insert foreign genes into a plant
Use a bacterium Use a particle gun Use a virus
113
What are marker genes
they identify which cells have taken up the desired gene
114
What techniques can be used to introduce genes into animals
liposomes in gene therapy injecting DNA directly into the nucleus of fertilised genes using a retrovirus
115
What is 'Pharming'
use of GMOs to produce therapeutic proteins and vaccines
116
What are some of the concerns with GMO
Antibiotic resistance Harmful products Transfer of viruses from animals to humans
117
What are the environmental issues associated with GMO
transfer of genes to non-GMO plants via cross pollination | Increased use of chemicals to control resistant weeds and insects
118
What are the ownership issues associated with GMO
traditional yields are more expensive | GMO seeds are patented and only grown under a license therefore expensive

Biology Topic 5 (2 decks)

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