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Coordination and response Flashcards iGCSE Biology

Coordination and response Flashcards iGCSE Biology

iGCSE Biology Flashcards – All Topics

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[h] Coordination and response Flashcards iGCSE CIE Biology

[q] Accommodation Viewing Near & Distant Objects

[a]

  • Close/Near Objects (Mnemonic: CCCC)
    • Lens fatter
      • More light refracted
    • Ciliary Muscle contract/taut
    • Suspensory Ligament relax
  • Distant/Far Objects
    • Lens thinner
      • Less light refracted
    • Ciliary Muscle relax
    • Suspensory Ligament contract/taut
 

[q] Describe how eyes would adjust to focus on far-away objects?

[a]

  • Ciliary muscle relax and the suspensory ligament becomes taut, causing the lens to become thinner
  • Effect
    • Light entering the lens is refracted less
    • So, image produced on retina is sharper
 
  • ref to image on, fovea / retina;
  • ciliary body / ciliary muscle, relax;
  • suspensory ligament(s) becomes taut / AW e.g. ‘pulled’; NOT ‘contract’,’stretched’
  • lens is, made thin(ner) / less convex / flat(ter) / AW;
  • less refraction of light; A bending, correct ref to focal length
 

[q] Difference between voluntary actions and involuntary actions?

[a]

  • Voluntary action involves (brain in) decision making / conscious;
  • Voluntary action is slower;
  • Voluntary action not reflex / automatic;
  • Voluntary action can be learned;
  • Voluntary action can give different responses to same stimulus;
 

[q] Drugs and Synapses

[a]

  • Many drugs produce their effects by interacting with receptor molecules at synapses. 
  • E.g:
    • Stimulants: (e.g: Heroin, Caffeine)
      • Stimulates receptor molecules in synapses in the brain, triggering the release of neurotransmitters like dopamine and serotonin into the synapse
    • Depressants​: (e.g: Alcohol)
      • Inhibit synapses by blocking the receptors ​on the postsynaptic neurone so that​ impulses cannot be sent​.
 

[q] Endocrine System

[a]

  • Ductless glands that produce hormones in animals are known collectively as the endocrine system
  • Endocrine glands have a good blood supply as when they make hormones they need to get them directly into the bloodstream (specifically the blood plasma) as soon as possible so they can travel around the body to the target organs to bring about the response
  • Hormones only affect cells with target receptors that the hormone can bind to. These are either found on the cell membrane, or inside cells. Receptors have to be complementary to hormones for their to be an effect. 
  • The liver regulates levels of hormones in the blood; transforming or breaking down any that are in excess. 
 

[q] Explain how does the body lower blood glucose concentration in reference to pancreas and liver?

[a]

  • Insulin secreted / produced / released;
  • By pancreas;
  • Glucose absorbed (by liver / muscles);
  • Stored as / converted to glycogen;
 

[q] Explain the role of plant hormones in gravitropism?

[a]

  1. Auxin is a plant hormone
    • Made in root tip;
  2. Auxin diffuses throughout the plant;
  3. More auxin accumulates lower parts;
  4. Auxin stimulates cell elongation;
  5. Roots grow towards gravity, positive (tropic) response;
 

[q] Explain why the control of the concentration of glucose in the blood is an example of negative feedback?

[a]

  • Glucose concentration is kept, (near) constant / within narrow limits / AW;
  • Any change (in concentration), is detected / acts as a stimulus;
  • Correct ref to, glucose → glycogen / glycogen → glucose / increasing glucose concentration / decreasing glucose concentration;
  • Idea that it returns concentration to normal;
  • Idea that release of correctly named hormone, stops / switches off;
  • Ref to homeostasis;
 

[q] Explain why the lactic acid concentration in the blood in trained cyclist is different from the untrained cyclist after exercise?

[a]

  • Lower anaerobic respiration / more aerobic respiration;
  • Less lactic acid produced (during exercise);
    • Because more oxygen supplied to muscles;
  • Less oxygen debt;
  • Less oxygen required, to oxidise / breakdown, lactic acid;
  • (Breakdown) to glucose / carbon dioxide and water;
  • Quicker, removal / breakdown, of lactic acid;
  • Appropriate comparative data quote with units;
 

[q] Fill in the blank labels

[a]

 

[q] Fill in the blanks:

[a]
 

[q] Fill in the blanks:

[a]

[q] What is Gravitropism?

[a] A response in which parts of a plant grow towards or away from gravity is called Gravitropism.

 

[q] What is Homeostasis?

[a] The maintenance of a constant internal environment is called Homeostasis.

 

[q] Homeostasis

[a]

  • Homeostasis is the maintenance of a​ constant internal environment​ in organisms, despite external changes. 
  • Internal conditions must be maintained within ​set limits​ and if these limits are exceeded, negative feedback mechanisms​ work to correct the change and restore the internal environment to the optimum.
  • This allows the environment to be at an ​optimum for cells​ to function.
  • Example of Homeostasis: glucose, temperature, water, pH, ions, urea, carbon dioxide.
 

[q] What is a Hormone?

[a] A chemical substance, produced by a gland and carried by the blood, which alters the activity of one or more specific target organs is called a Hormone.

  • Chemical / substance, produced by a gland;
  • Transported in the blood (plasma);
  • Alters the activity of one of more specific target, organs / tissues / cells;

[q] How synapses work:

[a]

  1. Vesicle move towards the cell membrane and fuse with cell membrane.
  2. Neurotransmitter is released
  3. The neurotransmitter then diffuses across the synaptic cleft.
  4. Neurotransmitter binds to receptor on post-synaptic neurone
    • Neurotransmitter and receptor are complementary
  5. Impulse is triggered in the post-synaptic neurone.
  • Function of Synapses:
  • Ensures that impulses only travel in one direction only.
  • How? Neurotransmitter released on one side of synapse and receptors only found on the opposite side of synapse;

[q] Human Nervous System

[a]

Consists of:
  1. Central Nervous System (CNS)
    • Made up of the brain and the spinal cord.
  2. Peripheral Nervous System (PNS)
    1. Made up of nerves that connect the body to the CNS.
  • It allows us to make sense of our surroundings and respond to them and to coordinate and regulate body functions
  • Co-ordination is the way all the organs and systems of the body are made to work efficiently together
 

[q] Investigating Gravitrospism

[a]

  • Soak about 20 peas in water for a day and then let them germinate in a vertical roll of moist blotting-paper.
  • After 3 days, choose 12 seedlings with straight radicles and pin six of these to the turntable of a clinostat so that the radicles are horizontal.
  • Pin another six seedlings to a cork that will fit in a wide-mouthed jar. Leave the jar on its side.
  • A clinostat is a clockwork or electric turntable, which rotates the seedlings slowly about four times an hour. Although gravity is pulling sideways on their roots, it will pull equally on all sides as they rotate.
  • Place the jar and the clinostat in the same conditions of lighting or leave them in darkness for 2 days
Result
  • The radicles in the clinostat will continue to grow horizontally but those in the jar will have changed their direction of growth, to grow vertically downwards.
Interpretation
  • The stationary radicles have responded to the stimulus of one-sided gravity by growing towards it. The radicles are positively gravitropic.
  • The radicles in the clinostat are the controls. Rotation of the clinostat has allowed gravity to act on all sides equally and there is no one-sided stimulus, even though the radicles were horizontal.
 

[q] Name the Blue Stars

[a]

 

[q] Name the Blue Stars

[a]

 

[q] Name the Green Stars

[a]

 

[q] Name the Green Stars

[a]

 

[q] Name the type of Neurone

[a]

 

[q] Name the type of Neurone

[a]

[q] Name the Yellow Stars

[a]

 

[q] Name the Yellow Stars

[a]

 

[q] What is a Negative Feedback?

[a] The process where a change in a condition from a set level causes a series of actions that return the condition to the set level is called a Negative Feedback.

 

[q] Negative Feedback

[a]

  • Negative feedback is the process where a change in a condition from a set level causes a series of actions that return the condition to the set level. 
  • It works in the following way:
    • if the level of something rises, control systems are switched on to reduce it again
    • if the level of something falls, control systems are switched on to raise it again
  • Negative feedback mechanisms are usually a continuous cycle of bringing levels down and then bringing them back up so that overall, they stay within a narrow range of what is considered ‘normal’
  • E.g: glucose, temperature, water, pH, ions, urea, carbon dioxide
 

[q] What is a Nerve impulse?

[a] An electrical signal that passes along nerve cells called neurones is called a Nerve impulse.

 

[q] What is a Phototropism?

[a] A response in which parts of a plant grow towards or away from the direction from which light is coming is called a Phototropism.

 

[q] What is a Pupil Reflex?

[a]

  • The ​pupil​ of the eye can​ expand and contract ​to ​control the amount of light​ that enters the eye
    • This antagonistic action is carried out by two sets of muscles, ​circular muscles ​and ​radial muscles​.
  • High light intensity (Mnemonic: BCCC)
    • Pupil Constrict (Narrower)
      • Less light enters the eye
      • Reason: Retina protected from damage caused by too much light.
    • Circular Muscle Contract
    • Radial Muscle Relax
  • Low Light Intensity
    • Pupil Relax (Wider)
      • More light enters the eye
      • Reason: Enough light enter the eye to stimulate retina
    • Circular Muscle Relax
    • Radial Muscle Contract
 

[q] What is a Reflex Arc?

[a]

 Stimulus  
↓
Receptor generates electrical impulse
↓
Impulse travels to spinal cord along sensory neurone within spinal nerve
↓
  Relay neurone 
↓
Motor neurone 
↓
Effector
↓
Response
 
Receptor(s) / sensory cells / nerve ending, detects heat / stimulus;
(nervous / electrical) impulses;
Generated by (skin) receptor;
Travels to spinal cord along sensory neurone(s);
Within spinal nerve;
Synapse;
Relay / connector / inter–, neurone;
Motor neurone to effector / biceps / muscle;
 

[q] Sense organs (are?)

[a] Groups of receptor cells responding to specific stimuli (are called?)

groups of receptor cells ;
responding to specific stimuli ;

 

[q] State 3 effects of adrenaline on the body

[a]

  • Dilation of pupils;
  • Reduced blood flow through, digestive system / skin;
  • Increase in, blood pressure or heart rate / pulse / stroke volume;
  • Increase in breathing rate;
  • Increase in oxygen concentration in the blood;
  • Increase in glycogen converted to glucose;
  • Increase in glucose / sugar concentration in the blood;
  • Increase in respiration rate;
  • Increase in blood flow through the muscles;
  • Increase in awareness / anxiety / alertness;
  • Broncho-dilation / widen airways;
 

[q] What is a Synapse?

[a] A junction between two neurones is called a Synapse.

 

[q] Temperature control

[a]

  • In addition to the methods already described, the skin has another very important mechanism for maintaining a constant body temperature.
    • This involves arterioles in the dermis of the skin, which can widen or narrow to allow more or less blood to flow near the skin surface through the blood capillaries. 
  • Reactions to a ​low​ internal temperature:
    • Shivering ​- muscles contract to produce heat.
    • Vasoconstriction – narrowing (constriction) of the arterioles in the skin reduces the amount of warm blood flowing through blood capillaries near the surface.
    • Reactions to a ​high​ internal temperature:
      • Sweating​ – sweat evaporates from the skin, reducing the surface temperature.
      • Vasodilation – the widening of the arterioles in the dermis allows more warm blood to flow through blood capillaries near the skin surface and so lose more heat.

 

[q] There are three main types of neurone:

[a] sensory, relay and motor

  • Sensory neurones carry impulses from sense organs/receptors to the CNS (brain or spinal cord)
  • Relay neurones are found inside the CNS and connect sensory and motor neurones 
  • Motor neurones carry impulses from the CNS to effectors (muscles or glands)
 

[q] Type 1 Diabetes 

[a]

  • Type 1 diabetes is a condition where the blood glucose levels are not able to be regulated due to the failure of the islet cells to produce sufficient insulin.
  • This means that blood glucose levels are often far too high
  • The extra insulin causes the liver to convert glucose into glycogen, which reduces the blood glucose level
  • Symptoms of diabetes include
    • Extreme thirst, fatigue, blurred vision, frequent urination, weight loss, slow wound healing and loss of consciousness in extreme cases
  • People with Type 1 diabetes have to monitor their blood glucose levels throughout the day as their levels of physical activity and their diet affect the amount of insulin needed
  • They can help to control their blood glucose level by:
    • Injecting insulin
    • Controlled Diet – eating foods that will not cause large increases in blood glucose level,
    • Exercising, which can lower blood glucose levels due to increased respiration in the muscles
    • Regular blood glucose tests
 

[q] Voluntary & Involuntary Responses

Fill in the tables

[a]

 

[q] What are the symptoms of type 1 diabetes? 

[a] Fatigue, thirst, frequent urination, nausea, blurred vision, dizzy, slow wound healing.

 

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