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Biology1 > Topic 7 > Flashcards

Topic 7 Flashcards

1
Q

Explain tendons

A

-Non-elastic tissue which connects muscles to bone

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2
Q

Explain ligaments

A

-Elastic tissue which joins bone together

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3
Q

Explain joints

A

-Area where 2 bones are attached
-Allows body parts to move
-Made of fibrous connective tissue plus cartilage

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4
Q

Explain antagonistic muscle pairs

A

-Pair of muscles which pull is opposite directions
-One contracts as the other relaxes
-Extensors straighten joint
-Flexors bend the join

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5
Q

What is a sarcolemma, sarcoplasm

A

-Sarcolemma: Muscle Cell Membrane, has inwards folds named tubules which help spread electrical impulses
-Sarccoplasm: Muscle Cytoplasm containing Ca2+ ions

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6
Q

Explain Skeletal Muscle

A

-Made of large bundles of muscle fibres
-Sarcolemma which has inward folds some stick into sarcoplasm named tubules
-Tubules help spread electrical impulses throughout sarcoplasm
-Sarcoplasmic reticulum runs through sarcoplasm, stores and releaeses Ca ions needed for muscle contraction
-Lots of mitrochondria, for ATP, for muscle contraction
-Lots of long cylindrical organelles named myofibrils, made of specialised proteins for muscle contraction

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7
Q

Explain Myofibrils

A

-Darker bands are thick myosin filament
-Lighter bands are thin actin filaments
-Made of many short units named sarcomeres

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8
Q

Explain Myofibril bands

A

-A: Dark bands contain thick myosin overlapping with thin actin
-I: Light bands contain thin actin filament only
-Z: Ends of the sarcomere are marked with a Z Line
-M: M line is the middle of a myosin filament
-H: Contains myosin filament only

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9
Q

Explain Sliding filament theory

A

-Explains muscle contraction
-Myofilaments slide over one another to make sarcomeres contract
-Myofilaments do not contract, their length stays fixed
-Simultaenous contraction of many sarcomeres means myofibrils and muscle fibres contract
-Sarcomeres return to their original length when muscle is relaxed

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10
Q

Explain Myofilaments

A

-Both have globular heads capable of back and fourth movement

-Myosin head has a binding site for actin and ATP

-Actin filaments have binding site for myosin heads, actin-myosin binding site
-Tropomyosin and troponin and found inbetween actin filaments
-They are attached to eachother to help myofilaments move past eachother

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11
Q

Explain tropomyosin

A

-In resting muscle, actin-myosin binding site is blocked by tropomyosin held by troponin
-This prevents myofilaments sliding past each other as the head is unable to bind to actin-myosin bridge (actin filament)

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12
Q

Explain how muscle contraction is triggered by an action potential

A

-A.P from motor neurone stimulates muscle cell, depolarising the sarcolemma
-Depolarisation spreads to the tubules to sarcoplasmic reticulum
-Sarco.Retic releases Ca2+ ions into the sarcoplasm which bind to troponin, causing a change of its shape
-Tropomyosin is pulled out of the actin-myosin binding site on actin
-Exposed binding site allows myosin head to bind
-Bond is formed, actin-myosin cross bridge,
-myosin head pulling the actin filament in a rowing action

-Ca2+ also activates ATPase… next card

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13
Q

Explain how ATP plays a role in the actin filament (actin-myosin binding site)

A

-ATP provides energy for the myosin head to move to the binding site
-Ca2+ activated ATPase which breaks down ATP to provide the energy
-Energy released then moves the myosin head pulling the actin filament in a rowing action

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14
Q

Explain ATP breaking cross bridges

A

-ATP from Ca presence provides energy to break the actin-myosin cross bridge
-This means the myosin head detaches after its movement
-Myosin head reattaches to a different binding site further up the filament
-A new actin myosin cross bridge is formed and the cycle repeats for as long as calcium binds to troponin

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15
Q

Explain what happens when excitation of muscle stops

A

-Muscle is no longer stimulated, Ca2+ ions are no longer released
-Ca2+ ions on troponin leave their binding site and are actively transported back into Sarc.Retic
-Troponin returns to its original shape pulling tropomyosin molecules with them which now block the actin-myosin binding site
-This means muscle no longer contracts as myosin head does not bind causing a rowing action

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16
Q

Explain slow twitch muscles

A

-Muscles that contract slowly e.g posture ones - in your back
-Great for endurance activities e.g long running
-Can work for long without fatigue
-Energy is released slowly via aer.resp, mitochondria and blood vessels supply oxygen
-Reddish in colour due to high myoglobin amount - myoglobin stored oxygen

17
Q

Explain fast twitch muscles

A

-Muscles that contract rapidly
-Muscles used for fast movement e.g in eyes or legs
-Great for short burst of speed and power
-Fatigues quick
-Energy released quickly via aer.resp, using glycogen (stored glucose)
-Fewer mitochondria and blood vessels
-Whitish in coour due to less myoglobin count therefore less O2 stored

18
Q

Explain aerobic respiration

A

-Process of large energy release by splitting glucose into CO2 and H2, which forms H2O
-Energy released is used to phosphorylate ADP to ATP, to provide energy for biological processes
-4 stages: glycolysis, link reaction, krebs cycle, oxidative phosphorylation
-Products from first 3 stages are used in 4th stage to produce many ATP
-Coenzymes (NAD, FAD) are used to transfer H from one molecule to the next

19
Q

Explain glycolysis

A

-Occurs in cytoplasm
-Glucose (6C) is phosphorylated using 2x ATP, 2x Phos added to sides of glucose
-Splitting of 1x glucose (6C) into 2x triose phosphate (3C), 1Phos on side of 3C
-Phosphorylation occurs again, 2x Phos on both sides of both triose phosphate
-Triose Phosphate is oxidised to form 2x Pyruvate (3C) (phosphate is removed from molecule)
-2x NAD + H -> reduced NAD and 2x ADP +Pi -> ATP
-Net: 2 ATP produced, 2x Pyruvate + H2O, 2x NADH + 2H

20
Q

Explain link reaction

A

-Occurs in matrix of mitrochondria, active transport via transport protein across mitochondrial envelope, using H ion.
-Occurs twice for every glucose molecule since 2x Pyruvate is made
-Decarboxylation and dehydrogenation of 3C is catalysed by pyruvate dehydrogenase
-Dehydrogenation occurs: 1x NAD -> Reduced NAD
-Pyruvate is decarboxylated from 3C -> 2C (Acetyl), lost carbon is in CO2 form
-Acetyl combines with coenzyme A to form acetyl-CoA
-Net: 2x acetylCoA goes into krebs, 2x CO2 is waste
-Net: 2x Reduced NAD is formed

21
Q

Explain krebs cycle

A

-Occurs in matrix of mitrochondria and occurs twice (since 2 acetylcoa)
-Coenzyme A released from Acetyl
-Acetyl (2C) reacts with acetate (4C) to form citrate (6C)

-Dehydrogenation occurs on Citrate (6C), producing reduced NAD
-Decarboxylation occurs, CO2 wasted, citrate becomes 5C
-Dehydrogenation occurs on 5C, producing reduced NAD
-Decarboxylation occurs again on 5C, CO2 wasted, becomes 4C
-substrate level phosphorylation occurs, 1x ADP + Phos -> ATP

-4C combines with CoA temporarily
-Dehydrogenation occurs twice on 4C, reduced FAD and reduced NAD produced
-A new 4C is produced (oxaloacetate is regenerated allowing cycle to repeat)
-Net: 3x reduced NAD, 1x reduced FAD, 2x CO2, 1x ATP (ONE ACETYL)

22
Q

Explain oxidative phosphorylation

A

-Inner mitochondria membrane is an ETC and ATP synthase
-Reduced NAD and reduced FAD transfers 2 high energy electrons into the ETC becoming unreduced
-Electrons move down the ETC, reducing and oxisiding ETC proteins
-Electron moves and energy is lost which is taken by ETC proteins to pump protons from matrix into intermembrane space - proton conc gradient increases here
-Protons move down the gradient into the ATP synthase. The energy from movement is used to create ATP whilst pushing protons into matrix. - This is chemiosmosis
-In the matrix, at end of ETC, electrons combine with 1/2oxygen and 2H to produce H2O
-Oxygen is named the final electron acceptor

23
Q

Explain anaerobic respiration

A

-Respiration without oxygen
-Only glycolysis occurs
-Lactate fermentation occurs in animals and produces lactate
-After glycolysis occurs, reduced NAD is converted into NAD and lactic acid is produce
-Glycolysis produces a net of 2 ATP which can keep biological processes going

-Lactic acids needs to be broken down by
-Converting it back to pyruvate to go into krebs cycle
-Liver cells converting it into glucose to be respired or stored

24
Q

Explain cardiac muscle

A

-Cardiac muscle controls the regular beating of the heart
-It is myogenic meaning it can contract and relax without signals via neurones
-SAN in the RA sets the rythm of the heartbeat by sending out waves of electrical activity to atrial walls
-This causes RA and LA to contract in sync
-A band of non conducting collagen tissue prevents electrical wave passing into ventricles from atria
-AVN is responsible for passing waves of electricity onto the bundle of his
-Bundle of his is a group of muscle fibres which conduct electrical waves to finer muscle fibres in the ventricular walls named purkyne fibres
-Purkyne fibres carry electric wave to muscular walls of ventricles to contract in sync

25
Q

Explain electrocardiograph

A

-P wave is atrial contraction (wave of depolarisation)
-QRS complex is ventricular contraction (wave of depolarisation)
-T is ventricular relaxaton (wave of repolarisation)

-Can be used to diagnose heart issues e.g heartbeat is fast or slow

26
Q

Explain breathing rate by medulla oblongata

A

-Medulla oblongata controls breathing rate and has 2 ventilation centres inspiratory and expiratory
-Inspiratory centre sends nerve impulses to diaphragm muscles causing contraction
-This increases volume and lowers pressure in the lungs
-Inspiratory can also send singals to expiratory to inhibit its actions
-Air enters lungs due to pressur e difference between outside and inside
-The lung’s stretch receptors are stimulated and send impulses to medulla oblongata which inhibit inspiratory centre
-Expiratory centre becomes uninhibited which sends nerves to diaphragm to relax causing lungs to deflate and the body to exhale
-The stretch receptors inactivate, inspiratory centre unihbits and the cycle repeats

27
Q

Explain breathing rate by excersise

A

-Excerise increases breathing rate by decreasing blood pH
-During excersise, CO2 levels increase and decreases blood pH
-Chemoreceptors in the medulla oblongata, aortic and carotid bodies detect a decrease in blood pH
-A nerve impulse is sent to medulla oblongata which sends more frequent nerves to the diagragm
-This increases rate and depth of breathing also triggering an increase in speed of gas exchange

28
Q

Explain heart rate by medulla oblongata

A

-Medulla oblongata controls heart rate via the cardiovascular control centre
-The CCC controls the rate at which the SAN fires - the SAN generates electrical impulses causing contraction
-Animals need to alter heart rate to respond to internal stimuli e.g not faint
-Chemical receptors detect stimuli e.g baroreceptors detecting pressure changes in aortic and carotid bodies and chemoreceptors to monitor O2 and CO2 levels in the blood
-Eletrical impulses are sent to the medulla oblongata along sensory neurones
-CCC processes the information and sends it to SAN through para/sympathetic neurones
-Sympathetic is the fight or flight response - increases heart rate
-Parasympathetic is the rest and digest response - reduces heart rate

29
Q

Explain homeostasis

A

-Maintenance of a stable internal enviroment, involves control systems to keep your body in narrow limits
-Keeping the internal enviroment constant is vital for cells to function normally (>40 = denature enzymes)
-Cells need a constant energy supply so blood glucose concentration must be stable - this is monitored by the pancreas
-Water is essential to keep the body functioning, blood water levels must be constant - regulated by kidneys

30
Q

Explain homeostasis negative feedback

A

-Used to reverse a change
-Homeostatic systems involve receptors, comms system and effectors
-Receptors detect when a level is high or low and this information is relayed via nervous system or hormonal system to effectors
-Effectors respond to counteract the change bringing the level to normal and is named the negative feedback mechanism
-Negative feedback keeps things around the normal limit e.g body temp to 37
-If a change is too big, effectors may not be able to counteract e.g huge body temp change

31
Q

Explain positive feedback

A

-Used to amplify a change from normal levels
-Some changes may react positively
-The effectors respond to further change the levels
-Positive feedback aims to rapidly activate something e.g blood clot
-Isnt involved in homeostasis as it does not stable the levels

32
Q

Explain mechanisms to change body temperature

A

-Sweating, more sweat secreted from sweat glands when hot which evaporates from the body
-Hairs provide insulation by trapping air, when hot the pili muscles relax to not trap air and provide less insulation for heat loss
-Vasodilation, more blood flows through capillaries so more heat is lost from the skin by radiation

-Shivering, muscles contract in spasms. More heat is produced from inreases respiration
-Less sweating, less sweat loss reducing amount of heat loss
-Vasoconstriction, arterioles constrict reducing blood flow and heat loss via radiation
-Hormones, body produces more adrenaline and thyroxine to increase metabolism leading to producing more heat

33
Q

Explain hypothalamus

A

-Controls body temperature
-Hypothalamus recieves information about temperature from thermoreceptors
-Thermoreceptors send impulses along sensory neurones to hypothalamus which sends impulses along motor neurones to effectors (muscles & glands)
-Effectors respond to restore body temperature back to the normal level

34
Q

Explain hormones and transcription factors

A

-Proteins called T.F control transcription of genes by binding to DNA sites near start of genes and increasing or decreasing rate of transcription (increase = activate, decrease = repress)
-Some hormones work inside cells e.g normal temp means thyroid hormone receptor binds to DNA at start of gene, decreasing transcription for a protein to increase metabolic rate
-So at colder temperatures thyroxine is released to bind to the thyroid hormone receptor

35
Q

Explain surgery in sports

A

-Keyhole surgery is a way of doing surgery without making a large incision
-Surgeons make a smaller incision and insert a video camera and specialised medical instruments through the incision
-Operations dont involve opening patient, less blood loss and less scarring
-Patient feel less pain and recover faster, athelete can return to competing quicker

-Prostheses can replace damaged body parts e.g used to replace whole limbs or parts of limbs
-Prostheses can include electronic devices that pick up signals sent by the nervous system
-Those with damages knee joints can have protheses ones
-Metal device is inserted into kneww to replace damage cartilage and bone-

Biology1 (9 decks)

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