cells

Question 1

what can light microscopes let us see?

Answer 1

they can let us see structures like a nuclei and mitochondria

Question 2

what does an electron microscope let us see?

Answer 2

let us see the internal structures of chloroplast and mitochondrion

Question 3

what is the equation for magnification ?

Answer 3

magnification M = size of image I ÷ real size of the object A

Question 4

what is Gonorrhoea and how can it be treated?

Answer 4

• sexually transmitted disease
• causes thick yellow or green discahrge from the penis or vagina
• pain when urinating
• ## can be controlled with antibiotics or a barrier method

Question 5

what are the human bodies defence mechanisms

Answer 5

1) nasal hairs , sticky mucus and cilia prevent the pathogens entering through the nostrils
2) stomach acid (ph1) kills most of the pathogens
3) skin , hard to penetrate waterproof barrier. Glands secrete oil which kill microbes
4) respiratory system is lined with mucus to trap dust and pathogens. cilia move to the mucus upwards to be swallowed

Question 6

what are 3 three ways white blood cells act to defend the body?

Answer 6

1) they engulf the pathogens and digest them this is called phagocytosis
2) they identify the antigen on the pathogen. they make specific antibodies to destroy the pathogens
3) bacteria may produce toxin (poison). white blood cells release specific antitoxins and neutralise the effect of the toxin.

Question 7

what are the chemicals used and hat are the positive and negative test results?

1) starch
2) glucose
3) fat
4) protein

Answer 7

the chemical iodine solution

1) starch pos- blue/black neg- orange/yellow
2) glucose doesn’t react with iodine will stay red/yellow
3) fat pos- dark neg- stays the same as the iodine solution
4) protein pos-purple neg- yellow/orange

Question 8

what is the function of a root hair cell and what features does it have?

Answer 8

to absorb water and minerals from the soil.

1) nucleus
2) cytoplasm
3) cell membrane
4) cell wall
5) permeant vacuole

Question 9

what is the function of a red blood cell and what features does it have?

Answer 9

to carry oxygen around the body

1) cytoplasm containing haemoglobin
2) biconcave discs with no nucleus, carry oxygen

Question 10

what are the adaptations of the small intestine?

Answer 10

• internal surface covered in millions of folds and villi
• villie increase surface area
• villie have good blood supply
• maintains concentration gradient
• membranes very thin short diffusion distance

Question 11

what are the adaptions of the lungs?

Answer 11

• lungs contain small air sacks called alveoli
• alveoli increase surface area
• alveoli good supply
• maintains concentraion gradient
• membranes very thin short diffusion distances