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GCSE BIOLOGY⏱🌱 > B3 > Flashcards

B3 Flashcards

(62 cards)

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1
Q

Which parts make up the nervous system?

A

The brain, spinal chord and neuroses make up the nervous system

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2
Q

What is the job of the nervous system?

A

It is the job of the nervous system to react to the surrounding and coordinate behaviour

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3
Q

Explain how the nervous system works

A

1) Sensory receptors (in skin, eyes) detect a stimulus (change in the environment)
2) they send the information as an electrical impulse on a sensory neurons to the central nervous system
3) the central nervous system coordinates a response and sends this on a motor neurons to an effector
4) the effect or responds

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4
Q

How is a neurone adapted to its function?

A

A neurone has

  • dendrites (which branch to connect with other neuroses)
  • long axon (which speeds up impulses)
  • myelin sheath (acts as an insulator to the axon to speed up impulses)
  • axon terminals ( release transmitter chemicals across a synapse to set off a new impulse in the next neruone.
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5
Q

What are reflex actions?

A

Reflex actions are automatic responses that play a protective role and do not involve the conscious brain to make them faster

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6
Q

Describe the reflex arc

A

1) A receptor detects a stimulus (change in the environment)
2) the information is sent along a sensory neurons to the central nervous system
3) at the central nervous system (spinal chord or unconscious part co the brain) the information is passed Kong a relay neurone
4) the information is then sent as electrical impulses to the right motor neurons
5) the motor neurons reaches the effector which carries out the response

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7
Q

Name the 7 parts of the eye and thief functions

A

Cornea- refracts light into the eye
Iris- controls how much light enters the pupil
Pupil- let’s light into the eye
Lens- focuses light onto the retina as it is elastic and can change shape
Cillary muscles/ suspensory ligaments- change the shape of the lens
Retina - covered in rods which are sensitive in dim light and cones which are sensitive to colour to detect light
Optic nerve - carries impulses from the receptors to the brain

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8
Q

How does the eye focus on distant objects?

A

1) the cillary muscles relax pulling the suspensory ligaments tight
2) the lens is less rounded so light is refracted less

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9
Q

How does the eye focus on close objects?

A

1) cillary muscles contract which slackens the suspensory ligaments
2) the lens is round so light refracts more

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10
Q

Why are some people long sighted?

A

Long sighted people are unable to focus on near objects because:

  • the lens is the wrong shape
  • the eyeball is too short

Which means near objects are focused behind the retina

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11
Q

How can people who are long sighted be treated?

A

People who are long sighted can wear glasses or contact lenses with a convex lens to correct it

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12
Q

Why are some people short sighted?

A

Short sighted people are unable to focus on distant objects because:

  • the lens is the wrong shape
  • the eyeball is too long

Distant objects are focused in front of the retina

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13
Q

How can people who are short sighted be treated?

A

Poole who are long sighted can wear glasses or contact lenses with a a concave lens to correct it or have corneal laser surgery

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14
Q

What is colour blindness? How can it be cured?

A

Colour blindness is when a person cannot tell the difference between certain colours. The most common is red-green colour blindness caused by the red or green comes in the retina not working properly.
It cannot be cured but tinted lenses can help

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15
Q

Name the five parts of the brain and their functions and label them on a diagram

A

Cerebrum- the outer but responsible to consciousness, intelligence, memory and language
Cerebellum - responsible for muscle control
Medulla- controls unconscious activity like breathing and heart rate
Hypothalamus- maintains body temp and produces hormones that control the pituitary gland
Pituitary gland- produces hormones (eg those in the menstrual cycle)

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16
Q

Which methods can be used to study the brain?

A

Case studies - studying people with abnormal brain function or damage can help determine which part of the brain are responsible for which functions

MRI scans- show which parts of the brain are active during activities to determine which parts are responsible for which functions

Examinations- the structure of the brain can be studied using dead people’s brains

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17
Q

What are the problems with studying the brain?

A
  • the brain is delicate and hard to get to because of the skull
  • people with severe brain damage may not be able to give informed consent to be part of a case study
  • people must donate their brains to study dead brains
  • results on an MRI scanner may not reflect a normal situation
  • the CNS doesn’t repair itself
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18
Q

How do hormones work?

A

Hormones are produced by the endocrine glands and released into the blood where they travel around the body and affect the target cells in the target organs due to the receptors that respond to that organ.

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19
Q

What is adrenaline?

A

Produce by the adrenal glands and prepares the body for fight or flight by increasing the the oxygen and glucose to cells. It does this through binding to receptors in the heart to increase heart rate and blood pressure which increases blood flow to muscles providing more oxygen and glucose for respiration. It also binds to receptors in the lever to break down glycogen to release glucose to cells.

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20
Q

What is thyroxine?

A

Produced by the thyroid gland in the neck and regulates the metabolism (chemical reactions in the body) it’s part of growth and protein synthesis.

It’s released in response to TSH (thyroid stimulating hormone) by the pituitary gland

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21
Q

How are hormones controlled?

A

Hormones are controlled by negative feedback; if the body directs the level of a substance is too high/low it triggers a response

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22
Q

Definition of testosterone

A

the main male sex hormone produce in the testes stimulates sperm production and is important and development of male reproductive system

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23
Q

Definition of oestrogen

A

oestrogen is the main female sex hormone produced in the ovaries . It causes the lining of the uterus to thicken and grow, stimulates the production of LH and inhibits the production of FSH.

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24
Q

Definition of progesterone

A

progesterone is a sex hormone produced in the ovaries and maintains the lining of the uterus during pregnancy inhibits the production of FSH and LH.

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25
Definition of FSH
FSH is a hormone produced in the pituitary gland which causes an egg to mature and stimulates the production of oestrogen
26
Definition of LH
LH is a hormone produced in the pituitary gland which stimulates the release of an egg and progesterone production
27
Explain the process of the menstrual cycle
1) Day 1-4 : FSH stimulates an egg to mature and the production of oestrogen 2) Day 4 -14: oestrogen causes the uterus lining to thicken and stimulates the production of LH and inhibits FSH 3) Day 14: LH stimulates the release of an egg which also stimulates progesterone production 4) Day 14-28: could just trying maintains the uterus lining inhibits FSH and LH as progesterone levels drop FSH levels increase in the whole cycle starts again
28
How do progesterone contraceptive methods work
progesterone contraceptive methods stimulate the production of thick cervical mucus to make it less likely for sperm to meet an egg
29
Give 4 examples of progesterone contraceptive methods
Progesterone contraceptive methods include the injection, patch, mini pill and IUS
30
How to oestrogen and progesterone contraceptive methods work?
Oestrogen and progesterone contraceptive methods work providing all of the effects of progesterone such as the thick cervical mucus that is a slightly more effective due to the oestrogen which inhibits FSH and thus inhibits ovulation
31
Two examples of oestrogen and progesterone contraceptive methods
The combined pill and the patch
32
How do barrier contraceptive methods work ?
Barrier contraceptive methods work by stopping the egg and sperm meeting
33
Give three examples of barrier contraceptive methods
condoms , femedoms and diaphragms
34
What are IUD's and how do they work?
IUD's are copper devices inserted into the uterus the copper ions cause thick cervical mucus form making it less likely for a sperm to meet an egg.
35
What are natural methods ?
Natural methods include either not having intercourse during ovulation or pulling out before ejaculation to avoid pregnancy
36
Give two examples of natural contraceptive methods
natural family planning and withdrawal
37
What is sterilisation ?
Sterilisation is a contraceptive method with surgery on either sex stops the egg or the sperm travelling
38
What are auxins?
Auxins are produced in the tips and control growth in the shoots and roots of plants they are responsible for phototropism and gravitropism. They also inhibit shedding and are produced in young leaves .
39
Are shoots positively or negatively phototropic and why?
Shoots are positively phototropic as when they are exposed to light the auxins move away as auxins a light sensitive which means the other side is gross motor and bends towards the light
40
Are shoots positively or negatively gravitropic and why?
Shoots and negatively gravitropic as when A shoot grows horizontally gravity cause more auxins together on the lower side causing it to grow faster making the shoot bend upwards
41
Are roots positively or negatively phototropic?
Roots are negatively photo trophic As when they are exposed to light the auxins move to the other side as auxins are sensitive to light Auxins inhibit cell elongation and roots so the other side will grow more causing the route to grow and bend downwards away from the light
42
Are roots positively or negatively gravitropic and why?
Roots are positively gravitropic as when horizontal auxins will collect on the bottom and inhibit growth therefore the other side grow more and bend downwards.
43
How can we investigate plant growth responses in the lab?
1) Put 10 crest seeds in three different Petra dishes each lined with most filterpaper 2) Shine a light on to one of the dishes from above and two of the dishes from different directions 3) leave for one week and when returned you should see that the ceilings have grown towards the light
44
Give two uses of auxins
1) Selective herbicide – weedkillers that only affect broadleaved plants leaving grass/crops untouched 2) Rooting powder is – the produce roots on cuttings of plants to make new plants which enable us to produce clones
45
What are gibberellins
Gibberellins a plant hormone that helps see germination cell growth and flowering
46
What is Ethene?
Ethan is a plant hormone which regulates plant development like cell division and shedding. Causes fruit to ripen
47
Give two uses of gibberellins?
– Controlling dormancy – they can alter when seeds germinate so all in a batch germinate at the same time/earlier than they normally would – Producing large and seedless fruit
48
What is the use of ethene?
- Stimulates fruit ripening – which is useful to ripen fruits just before they’re sold
49
Definition of homoeostasis
Homoeostasis is it is the controlling of internal conditions through negative feedback
50
How does the body control body temperature
Because enzymes work best at 37 degree The hypothalamus in your brain acts as a thermostat if contains receptors are sensitive to blood temperature and impulses from skin receptors provide information about external temperature
51
What happens when the hypothalamus detect that the body temperature is above normal?
1) Erector muscles relax so hair lies flat 2) Lots of sweat is produced by the sweat glands when its wet evaporates it transfers energy from your skin to the environment cooling you down 3) blood vessels vasodilate Langrell bloodflow near the surface so more energy is transferred to the surroundings
52
What happens when the hypothalamus detect that the body temperature is below normal?
1) Erector muscles contract has stand up to trump an insulating layer of air helping keeping you warm 2) Blood vessels vasoconstrict meaning less blood flows near the surface so less energy is transferred to the surroundings 3) Muscles contract causing you to shiver increasing respiration which transfers energy to warm the body
53
How does the body control blood sugar level
Blood sugar level is controlled by the pancreas. Using hormones insulin and glucagon
54
What happens in the pancreas detects blood glucose levels are too high?
Insulin is added to the blood by the pancreas which causes the liver to turn glucose into glycogen
55
What happens in the pancreas detects blood glucose levels are too low?
If the pancreas detects the blood glucose levels are too low glucagon is added to the blood which causes the liver to turn glycogen into glucose
56
What is type one diabetes?
If a person suffers with type one diabetes the pancreas doesn’t produce insulin the blood sugar can get so high it can kill them. People need insulin injections regularly and limit carbohydrates and exercise regularly
57
What is Type 2 diabetes?
The person has Type 2 diabetes they become resistant to insulin which can also lead to blood sugar levels rising to a dangerous level. Being overweight can increase your chance so a healthy diet and exercise along with drugs can help
58
Is it important to control water content in the body?
It’s important to control water content in the body because cells are surrounded by tissue fluid which gives them everything they need but it’s too much water moves in a cell by osmosis it will burst (lysis ) Or too much water moves out by osmosis it will shrink
59
How do the kidneys work?
1) blood enters the kidneys through the renal artery into one of the million filtering units called nephrons 2) each nephron has a sieve like structure called a glomerus which only lets small molecules such as water, sugar, salt and urea to pass into the Bowmans capsule to the tubles 3) the small molecules then passed through the tubles around the loop of Henle where all of the sugar, some salt and water is selectively reabsorbed back into the capillaries and into the blood 4) then the urea, excess water and excess salt forms urine which flows through the collecting duct back and is excreted by the kidneys
60
How is urine concentration controlled ?
The concentration of urine is controlled by the hormone ADH which is released by the pituitary gland based on a negative feedback system.
61
What happens if blood water levels get too high?
The receptors in the hypothalamus detect the change in water level in the blood so the pituitary gland secretes less ADH which means the tubles in the kidneys are less permeable they reabsorb less water and a vast quantity of dilutes urine is produced
62
What happens if blood water levels get too low?
The receptors in the hypothalamus detect the change in water level in the blood so the pituitary gland secretes morr ADH which means the tubles in the kidneys are more permeable they reabsorb more water and a small quantity of concentrated urine is produced. The thirst mechanism is also activated

GCSE BIOLOGY⏱🌱 (6 decks)

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