Biology Topic 7

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  • Created by: sophie_rw
  • Created on: 26-03-19 18:10
Ligament
Attach bones to other bones, holding them together. Control and restrict amount of movement in the joint.
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Cartilage
Protects bones within joints by absorbing shock.
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Synovial fluid
Fluid that acts as a lubricant as it enables bones to move freely.
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Tendon
Attach muscles to bone, enables muscles to power joint movement.
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Flexor
A muscle that bends a joint when it contracts .
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Extensor
A muscle that straightens a joint when it contracts.
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Antagonist pairs
Muscles that work together to move a bone by creating opposite forces.
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Skeletal muscle
Type of muscle you use to move
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Why do muscles work in pairs
Because they can only pull when they contract so they must create opposite forces to move a bone.
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What is skeletal muscle made up of
Large bundles of long cels called muscle fibres.
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Why are muscle cells multinucleate
A single nucleus could not effectively control metabolism of such a long cell- maximised protein synthesis.
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Transverse (T) tubules
Formed by parts of the sarcolemma folded inwards into the sarcoplasm. They help to spread electrical impulses throughout the sarcoplasm so they reach all parts of the muscle fibres.
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Sarcolemma
Cell membrane of muscle fibre cells.
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Sarcoplasmic reticulum
Network of internal membranes that run through the sarcoplasm. It stores and releases calcium ions.
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Myosin
Thick myofilament, darker coloured.
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Actin
Thin myofilament, light band
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Myofibrils
Long, cylindrical organelles inside muscle fibres.
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Three types of muscles
Skeletal, smooth, cardiac
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Calcium ion
Required for muscle contraction.
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What are myofibrils made up of
Myosin and actin
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Sarcomere
One contractile unit in a muscle cell
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Sliding filament theory
Actin slides over myosin to cause sarcomeres to contract. The simultaneous contraction of lots of sarcomeres means the myofibrils and muscle fibres contract.
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What are the binding sites on myosin heads for
Actin and ATP
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Why are the myosin globular heads hinged.
So they can move back and forth.
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Names of proteins found between actin filaments.
Troponin and Tropomyosin
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What happens to troponin during muscle contraction and what is the effect of this
Calcium ion binds to the troponin, changin it’s shape so the tropomyosin is moved and the actin-myosin binding sites are exposed.
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What happens to the actin-myosin binding suite during muscle relaxation.
Blocked my tropomyosin which is held in place by troponin.
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What is the effect of the actin-myosin binding sites being blocked
Filaments can’t slide past each other
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What is formed when the actin-myosin binding site is exposed
Actin-myosin cross bridge is formed
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Why is ATP required for muscle contraction
Provides energy to move the myosin head and break the cross bridge to allow biding to the next binding site.
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What happens when a muscle stops being stimulated
Calcium ions leave their binding sites on the troponin and are active transported back into the sarcoplasmic reticulum. Troponin returns to original shape, pulling tropomyosin, causing it to block the actin-myosin binding site again.
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What are the folds in the inner membrane of the mitochondria called
Cristae
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Why do mitochondria increase the efficiency of respiration
Everything needed is in one place-speeds things up.
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How is ATP broken down
Hydrolysis
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What is ATP made up of
Adenine, ribose, and three phosphates
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What is a coenzyme
A molecule that aids an enzyme in it’s action
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What are the coenzymes involved in respiration
NAD, FAD and CoA
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Why does the link reaction occur in the mitochondrial matrix
The enzymes and coenzymes needed are located there. Reduced NAD is in the right place to be used by oxidative phosphorylation.
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How is acetate made from pyruvate
Pyruvate is carboxylated and then NAD is reduced by collecting hydrogen from pyruvate to form acetate.
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What happens to pyruvate during the link reaction
It is carboxylated as one carbon atom is removed to form co2.
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What are the stages of respiration
Glycolysis, Link reaction, Krebs cycle, Oxidative phosphorylation
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What are the products of the link reaction
Co2 and 2 Reduced NAD
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What are the products of one Krebs cycle
ATP, CO2, reduced NAD and reduced FAD
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Substrate level phosphorylation
Using glucose to produce ATP
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Where does the Krebs cycle take place and why
Each of the reactions is controlled by a specific intracellular enzyme which is found in the mitochondrial matrix.
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How many times do the link reaction and krebs cycle occur for every glucose molecule
Twice
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Where does glycolysis happen
Cytoplasm
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What happens during phosphorylation in glycolysis
Glucose is phosphorylase by adding 2 phosphate groups from 2 ATP molecules. 2 molecules of triose phophate and 2 molecules of ADP are made.
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What happens during oxidation in glycolysis
Triose phosphate is oxidised forming 2 pyruvate molecules. 2 NAD molecules are reduced to 2 reduced NAD. 4 ATP are produced but the net gain is 2 ATP.
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What is chemiosmosis
The movement of hydrogen ions across a selectively permeable membrane down their electrochemical gradient to generate ATP.
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What us released from reduced NAD and reduced FAD when they are oxidised
Hydrogen atoms
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What is oxidative phosphorylation
The process where energy carried by electrons from reduced NAD and reduced FAD is used to make ATP.
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What is the energy released from electrons in the ETC used for
Used by electron carriers to pump H+ ions into the inter membrane space.
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How is ATP made in the ETC
H+ ions move down electrochemical gradient back into the mitochondrial matrix via the ATP synthase enzyme. This movement drives the synthesis of ATP.
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What it’s the final electron acceptor
Oxygen
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What happens to lactate after a period of anaerobic respiration
Lactate in oxidisedback into pyruvate. The pyruvate is directly oxidised into co2 and h2o via Krebs Cycle. Some lactate is converted to glycogen and stored in liver cells.
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Aerobic respiration
Splitting of glucose to release co2 as a waste product and combining hydrogen with oxygen with the release of a large amount of energy.
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Metabolic pathway
Process of multiple processes with each process controlled and catalysed by a specific intracellular enzyme.
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Myogenic
Can contract and relax without external nervous stimulation.
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What coordinates the rhythmic sequence of contractions
Sinatrial and atrioventricular nodes.
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How does atrial contraction occur
Depolarisation of SAN generates an electrical impulse that spreads across the right and left atria.
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Why doesn’t the wave of electrical impulse pass directly from the atria to the ventricles
There is a band of non-conducting collagen tissue preventing this.
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Why is there a delay before the impulse is conducted from the AVN to the ventricles
It ensures that the atria have finished contracting and have emptied and the ventricles have filed with blood before they contract.
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Purkyne fibres
Large specialised muscle fibres that conduct impulses rapidly to the apex of the ventricles.
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Bundle of His
The right and left bundles of fibre the conduct the impulse in the walls of the ventricles.
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Why do the ventricles contract from the bottom up
Ensures blood is pushed into aorta and pulmonary artery.
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Electtrocardiogram
Graphic record of the electrical activity during the cardiac cycle.
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The heart depolarises when it...
Contracts
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The heart repolarises when it...
Relaxes
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What does the elecrocardiograph record
Changes in electrical charge using electrodes placed on the chest
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P wave
Depolarisation of atria leading to atrial systole.
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QRS Complex
Wave of depolarisation resulting in ventricular systole.
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PR Interval
Time taken for impulse to be conducted from SAN across the atria to the ventricles through the AVN.
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T wave
Repolarisation of the ventricles during the heart
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What does the height of the wave indicate
How much electrical charge passes through the heart
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How do doctors use ECGs
Compare the patient’s ECG to a normal trace to diagnose heart problems.
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Slow twitch muscle fibres
Contract slowly, used for posture and endurance, can work a long time without getting tired, energy released slowly through aerobic respiration, lots of mitochondria.
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Fast twitch muscle fibres
Contract very quickly, used for short bursts of speed and power, get tired quickly, energy released quickly through anaerobic respiration using glycogen, few mitochondria or blood vessels.
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How does the body take in more oxygen and breathe out more carbon dioxide during exercise
Increases breathing rate and depth, increases heart rate
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What controls rate of breathing
Ventilation centres in medulla oblongata
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What does the inspiratory centre do
Sends nerve impulses to the intercostal and diaphragm muscles to make them contract, also sends impulses to the expiratory centre to inhit its action.
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What happens when the inspiratory centre sends nerve impulses to the intercostal muscles and diaphragm
Volume of lungs increase which lowered pressure in lungs, air enters due to
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What happens when rate and depth of breathing increases
Gaseous exchange speeds up, co2 level drops and extra o2 is supplied for the muscles so the pH returns to normal and breathing rate increases.
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What happens when lungs deflate and expel air
Stretch receptors become inactive. Inspiratory centre is no longer inhibited and cycle starts again.
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What is ventilation rate
Volume of air breathed in or out in a period of time
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Why does the ventilation rate increase during exercise
because the breathing rate and depth increase
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What is cardiac output
Total volume of blood pumped by a ventricle every minute- heart rate x stroke volume.
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What is stroke volume
Volune of blood pumped by one ventricle each time it contracts
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Why does cardiac output increase during exercise
Heart rate and stoke volume increase
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What controls heart rate
Cardiovascular centre in medulla oblongata
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How does the cardiovascular centre control heart rate
Controls rate at which SAN fires electrical impulses
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What are baroreceptors and how are they stimulated
Pressure receptors in the aortic and carotid arteries which are stimulated by high and low pressure.
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How are chemoreceptors involved in heart rate
They monitor oxygen levels in the blood and also carbon dioxide and pH
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What does the cardiovascular centre do
Processes info from receptors and sends impulses to SAN along sympathetic and parasympathetic neurones which release different neurotransmitters onto SAN.
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When there’s high bp what is the neurone and transmitter that’s involved and how
Impulses are sent to cardiovascular control centre which sends impulses along parasympathetic neurones. These secrete acetylcholine which binds to SAN receptors
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What is response of the SAN when there’s hitch bp
SAN fires impulses less frequently to slow heart rate and reduce pressure back to normal
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When there’s low bp what’s the neurone and the transmitter that’s involved and how
Impulses are sent to the cardiovascular conrol centre which sends impulses long sympathetic neurones. These secrete noradrenaline which binds to SAN receptors
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What’s the response of the SAN when there’s low bp
SAN fires impulses more frequently to increase heart rate and return bp back to normal
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When there’s high blood oxygen, low CO2 or high pH levels, what’s the neurone and transmitter involved and how
Impulses sent to cardiovascular centre which sends impulse along parasympathetic neurones. These secrete acetylcholine which binds to SAN receptors
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What is the response of the SAN when there is high blood oxygen, low CO2 or high pH levels
SAN fires less frequently to decrease heart rate and return oxygen, carbon dioxide and pH levels back to normal.
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When there’s low blood oxygen, high CO2 or low pH levels what is the neurone and transmitters involved sand how
Impulses are sent to the cardiovascular which sends impulses along sympathetic neurones. These secrete noradrenaline which binds to receptors on SAN.
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What is the response of the SAN when there’s low blood oxygen, high CO2 or low pH levels
SAN fires impulses more frequently to increase heart rate and return levels back to normal
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Tidal volume
The volume of air breathed in and out at each breath at rest
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Total lung capacity
Volume of lungs at maximal inflation
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Breathig rate
Number of breaths taken per minute
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Oxygen consumption
Volume of oxygen used by the body
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Respiratory minute ventilation equation
Tidal volume x breathing rate
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Respiratory minute ventilation
Volume of gas breathed in or out in a minute
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Vital capacity
Maximum volume of air that can be breathed in and out
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Describe inhalation
Diaphragm contracts, intercostal muscles contract, chest volume increases, pressure in chest decreases, atmospheric pressure forces air into lungs, lungs expand to equalise pressure
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Describe exhalation
Diaphragm relaxes, intercostal muscles relax, chest volume decreases, pressure in chest decreases, air is forced out of lungs until air pressure inside and outside is equal
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Homeostasis
Maintaining a constant internal environment despite changes to external or internal environment
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What do homeostatic systems involve
Control systems that keep the internal environment within narrow limits, keeping the environment in a state of dynamic equilibrium
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Negative feedback
Mechanism that restores levels back to normal. It maintains systems within narrow limits. It only works within certain limits
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Positive feedback
Amplifies the change from the normal level. It does not keep the internal environment stable so is not invlived in homeostasis
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How is sweating involved in thermoregulation
More sweat is secreted from sweat glands when the body is too hot. The water in sweat is evaporated from the skin and takes away heat from the body, cooling it down. Much less sweat is secreted when cold, reducing heat loss
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How is shivering involved in thermoregulation
When it cold, muscles contract in spasms. This makes the body shiver and more heat is produced from increase respiration
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Vasodilation in thermoregulation
When hot, shunt vessels constrict and muscles in arterioles near the surface of the skin relax and so dilate, more blood flows through them, increasing blood flow close to the skin so more energy loss
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Vasoconstriction in thermoregulation
When cold, muscles in arteriole walls contract, causing them to constrict which reduces blood supply to capillaries. Blood is diverted through shunt vessel which dilates as more blood flows through it. Blood flows further from skin=less energy lost
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Role of hairs in thermoregulation
When hot, erector pili muscles relax so hairs lie flat. Less air trapped so skin less insulated and heat lost more easily. When cold, erector pili muscles contract, hairs stand up, prevent heat loss- heat is trapped
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Release of hormones in thermoregulation
Body releases adrenaline and thyroxine which increase metabolism, so more heat is produced
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What does the hypothalamus do
Maintains body temperature, receives impulses from thermoreceptors and then sends impulses along motor neurones to the effectors
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How do hormones affect activity of transcription factors
Some can cross the cell membrane, enter the cell and bind to the transcription factors
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How hormones affect transcription factors inside cells
At normal temp, thyroid hormone binds to DNA at start of gene=decreases transcription of gene coding for protein that increases met rate. At cold temp, thyroxine released-binds to thyroid hormone receptor. Transcription rate increases=more protein=me
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Other cards in this set

Card 2

Front

Cartilage

Back

Protects bones within joints by absorbing shock.

Card 3

Front

Synovial fluid

Back

Preview of the front of card 3

Card 4

Front

Tendon

Back

Preview of the front of card 4

Card 5

Front

Flexor

Back

Preview of the front of card 5
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