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Biology GCSE > Cells And Control 🧫 > Flashcards

Cells And Control 🧫 Flashcards

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1
Q

What is diffusion?

A

Diffusion is the net movement of particles from an area of high concentration to an area of lower concentration.

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2
Q

What factors affect diffusion?

A

Temperature, concentration gradient, membrane surface area

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3
Q

How does membrane surface area affect diffusion?

A

The larger the surface area of the membrane that a substance is diffusing through (e.g. the membrane around a cell), the faster the rate of diffusion.

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4
Q

How does temperature affect diffusion?

A

The higher the temperature, the faster the rate of diffusion.

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5
Q

How does concentration gradient affect diffusion?

A

The bigger the difference in concentration between two areas, the greater the concentration gradient and the faster the rate of diffusion.

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6
Q

What is osmosis?

A

Osmosis is the diffusion of water across a partially permeable membrane from a dilute solution (high concentration of water) to a concentrated solution (low concentration of water).

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7
Q

What is an independent variable?

A

A variable which is controlled and is changed in the experiment

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8
Q

How do you calculate the percentage change in mass?

A

(final mass - initial mass)÷ initial mass x 100

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9
Q

What are the three main forms of transport in cells?

A

Osmosis, diffusion, active transport

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10
Q

What is active transport?

A

Active transport is the net movement of particles against a concentration gradient.
Energy is therefore required.

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11
Q

What is a dependant variable?

A

A dependent variable is what we measure in an experiment.

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12
Q

What a waste product is removed during diffusion at the lungs?

A

CO2

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13
Q

What are stem cells

A

Cells that have not yet undergone differentiation (unspecialised cells)

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14
Q

What happens when a cells differentiates

A

It becomes specialised

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15
Q

Give 3 examples of where stem cells are found in the body

A

Bone marrow
Muscle
Heart

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16
Q

Where does cell division in plants occur

A

In meristems

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17
Q

How do cells become differentiated in a meristem

A

As the shoot grows new cells are being produced continuously near the tip. These will eventually become differentiated and enlarge to form a vacuole

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18
Q

Why are stems cells useful to us

A

They have the potential to be transplanted into patients with a disease by replacing cells have been damaged or destroyed

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19
Q

What stem cells can be used for stem cell transplants

A

Embryonic stem cells (can differentiate into a wide range of cell types)
Adult stem cells ( can differentiate into a narrow range of cell types)

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20
Q

What are the ethical issues associated with embryonic stem cells used in medicine

A

At what stage of its development should an embryo be regarded as a person
Fear that embryos will come to be viewed as a commodity

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21
Q

What are the three main types of neurones

A

Sensory
Motor
Relay

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22
Q

Where do 2 neurones meet

A

A synapse

23
Q

How does an electrical signal travel across a synapse

A
  1. Electrical impulse travels along first axon
  2. Triggers the nerve ending of a neurone to release chemical messengers (neurotransmitters)
  3. These chemicals diffuse across the synapse and bind with receptor molecules on the membrane of the next neurone
  4. They only bind to the specific neurotransmitters released from the first neurone
  5. Stimulates the second neurone to transmit the electrical impulse
24
Q

What is the CNS

A

Central nervous system
(Brain & spinal cord)

25
Q

What are effectors

A

Include muscles and glands
Produce a specific response to a detected stimulus

26
Q

Flow diagrams to show how information flows from receptors to effectors

A

Stimulus —> receptor —> coordinator —> effector —> response

27
Q

Order of reflex arc

A

Stimulus —> receptor —> sensory neurone —> relay neurone —> motor neurone —> effector —> response

28
Q

What does the reflex arc do in order to increase the speed of a reaction

A

Pathway of reflex arc does not initially go to the brain

29
Q

Where is the medulla oblongata found

A

Top of the spinal cord

30
Q

Where is the cerebellum found

A

Base of brain at the back

31
Q

Where is the cerebrum found

A

Front of brain

32
Q

Describe the function of the medulla oblongata

A

Controls the unconscious activities such as heart rate and breathing rate

33
Q

Describe the function of the cerebellum

A

Controls balance, coordination of movement and muscular activity

34
Q

Describe the function of the cerebrum

A

Outer layer is split into two hemispheres which make up cerebral cortex
Controls most of our senses, intelligence, personality, conscious thoughts, language and verbal memory

35
Q

How can CT and PET scanners help overcome issues investigating functions of the brain

A

CT- series of x-rays from different angles are processed and allow doctors to see inside the brain
PET- detect gamma rays that radiate from a tracer injected by the patient. The tracer attaches to a tumour and so the pet scanner is often used to detect cancer

36
Q

What is the function of the cornea

A

Refracts light as it enters the eye

37
Q

What is the role of the lens

A

Further refracts light and focuses it onto the retina

38
Q

What is the role of the iris

A

Controls how much light enters the pupil

39
Q

What is the role of the retina

A

Contains light receptors

40
Q

What are the roles of the rods and cones in the retina

A

Rods are used for seeing in dim light as they are more sensitive to light than the cones
Cone cells produce colour vision

41
Q

What does the lens do to focus on a near object

A

The lens becomes thicker which allows the light rays to retract more strongly

42
Q

What does the lens do to focus on a distant object

A

The lens is pulled thin which allows the light rays to refract slightly

43
Q

How can short and long sightedness be corrected

A

Spectacle lenses or contact lenses which refract the light so the rays focus on the retina

44
Q

What is the difference between long and short sighted people

A

Short sighted - see nearby objects
Long sighted - can see objects for away

45
Q

What is cataract

A

A cloudiness in the lens caused by a build up of protein

46
Q

How can cataracts be corrected

A

Removing the lens and replacing it with a plastic lens

47
Q

Compare and contrast active transport and diffusion

A

Diffusion is net movement of particles from high to low concentration
Diffusion does not require energy
Diffusion occurs down a concentration gradient
(Active transport is everything opposite)

48
Q

Give an example of active transport

A

Plants use it to absorb nitrates from soil

49
Q

Give an example of diffusion

A

Oxygen diffuses from alveoli into the blood in the lungs

50
Q

What do relay neurones do

A

Carry electrical signals around the CNS

51
Q

What do motor neurones do

A

Carry electrical signals away from the CNS to effectors which are muscles or glands

52
Q

What is the purpose of the myelin sheath

A

Insulated the axon and speeds up the electrical signals

53
Q

How do painkillers stop someone feeling pain in terms of the CNS

A

Prevent neurotransmitters from binding to the receptors in the next neurone
Causes no electrical impulse to be triggered
Signal is not received by the CNS (person doesn’t feel pain)

Biology GCSE (17 decks)

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