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GCSE Biology > organisation > Flashcards

organisation Flashcards

1
Q

what are cells?

A

the basic building blocks that make up all living organisms

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2
Q

what is a tissue?

A

a tissue is a group of similar ccells that work togther to carry out a particular function

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3
Q

give 3 examples of mammal tissues and the ir functions

A

1) muscular tissue - contracts to move whatever its attatched to
2) glandular tissue - makes and secretes chemicals like enzymes and hormones
3) epithelial tissue - covers some parts of the body

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4
Q

what is an organ?

A

group of different tissues that work togther to perform a certain function

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5
Q

what are the 3 tissues the stomach is made up out of? describe their functions

A

1) muscular tissue - moves the stomach wall to churn up the food
2) glandular tissue - makes digestive juicess to digest food
3) epithelial tissue - covers the outside and inside of the stomch

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6
Q

what is an organ system?

A

a group of organs working together to perform a particular function

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7
Q

what are the 5 organs that make up the digestive system? describe their functions

A

1) glands - produce digestive juices
2) stomach and smal intestines - digest food
3) liver - produces bile
4) small intestine - absorbs soluable food molecules
5) large intestine - absorbs water from undigested food leaving faeces

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8
Q

what is a catalyst?

A

a catalyst is a substance which increases the speed of a reaction, whitout being changed or used up in a reaction

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9
Q

what is an enzyme?

A

a biological catalyst, a large protein, made up out of chains of amino acids folded into unique shapes, which enable the enzymes to do their jobs

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10
Q

the lock and key model is a simpler version of how enzyme action works, in reality what is the difference?

A

The active site changes shape slightly as the substrate binds to it, to get a tighter fit.
This is called the ‘induced fit’ model of enzyme action

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11
Q

Increasing the temperature increases the rate of enzyme action, but what happens if it gets too hot?

A

some of the bonds holding the enzyme together break, which changes the shape of the enzymes active sight, so the substrate won’t fit anymore. this enzyme is denatured

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12
Q

what happens if the ph is too high or too low?

A

it will interfere with bonds holding the enzyme togther, changing the shape of the active site, and denaturing the enzyme

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13
Q

what is the method for the practical on investigating the effect of pH on enzyme activity?

A

1) put a drop of iodine solution into every well on a spotting tile
2) place a bunsen burner on a heatprood mat, a tripod and gauze over the bunsen burner, an dthen heat the water until its 35 degrees. keep temp constant throughout the experiment
3) use a syringe to add 1cm cubed amylase solution and 1cm cubed of a buffer solution
4) use a different syringe to add 5 cm cuned of a starch solution to the boiling tube
5) immediately start the stop clock
6) use continuous sampling to record how long it takes for the amylaze enzyme to break down all the starch

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14
Q

what is the method for the practical on investigating the effect of pH on enzyme activity?

A

1) put a drop of iodine solution into every well on a spotting tile
2) place a bunsen burner on a heatprood mat, a tripod and gauze over the bunsen burner, an dthen heat the water until its 35 degrees. keep temp constant throughout the experiment
3) use a syringe to add 1cm cubed amylase solution and 1cm cubed of a buffer solution with a pH of 5
4) use a different syringe to add 5 cm cuned of a starch solution to the boiling tube
5) immediately start the stop clock
6) use continuous sampling to record how long
7) repeat this experiment with buffer solutions of different pH values, to see how pH affects the time taken for startch to be broken down
8) remember to control any variables each time to make it a fair test

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15
Q

how do you use continuous sampling in the enzyme activity practical?

A

use a dropping pipette to take a fresh sample from the boiling tube every 30 seconds and put a drop into a well. when the iodine solution remains browny-orange, starch is no longer present

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16
Q

rate of reaction =

A

1000 / time

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17
Q

why do big molecules like startch, proteins and fats need to be broken down into smaller molecules by enzymes?

A

they are too big to pass through the walls of the digestive system

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18
Q

What breaks down starch? into what?

A

amylase - maltose and other sugars

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19
Q

where is amylase made? (3 places)

A
  • salivary glands
  • pancreas
  • small intestine
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20
Q

what breaks down proteins? into what?

A

protease - amino acids

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21
Q

where is protease made? (3 places)

A
  • stomach
  • pancreas
  • small intestine
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22
Q

what breaks down lipids? into what?

A

lipase - glycerol and fatty acids

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23
Q

where is lipase made? ( 2 places)

A
  • pancreas

- small intestine

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24
Q

where is the bile:

1) produced
2) stored
3) released into

A

1) liver
2) gall bladder
3) small intestine

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25
Q

why is bile alkaline?

A

the hydrochloric acid in the stomach makes the pH too acidic for enzymes in the small intestine to work properly, the bile neutralises the acid and makes the conditions alkaline. The enzymes in the small intestine work best in these alkaline conditions

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26
Q

what is the main purpose of bile?

A

to emulsify fat - so it breaks down fats into tiny droplets giving a bigger surface area of fat for the enzyme to work on, which increases the rate of reaction

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27
Q

purpose of the salivary glands

A

to produce amyalse enzyme in saliva

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28
Q

purpose of the liver

A

to produce bile which neutralises stomach acid and emulsifies fat

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29
Q

purpose of the gall bladder

A

where bile is stored before being released into the small intestine

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30
Q

purpose of the large intestine

A

excess water is absorbed from the food

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31
Q

prpose of the rectum

A

where the faeces are stored before they leave through the anus

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32
Q

purpose of the stomach (3)

A
  • pummels food with muscular walls
  • produces the protease enzyme, pepsin
  • produces hydrochloric acid to kill bacteria and give the right pH for the protease enzyme (ph2)
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33
Q

purpose of the pancreas

A

produces protease, amylase and lipase enzymes and releases them into the small intestine

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34
Q

purpose of the small intestine

A

produces protease, amylase and lipase enzymes to complete digestion
where digested food is absorbed out of the digestive system into the blood

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35
Q

how do you prepare a food sample?

A
  • break up a piece of food with a pestle and mortar
  • transfer to a beaker and add some distilled water
  • give stir with glass rod to dissolve some of the food
  • filter the solution with a funnel lined with filter paper to get rid of the solid bits of food
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36
Q

what test is used for sugars?

A

benedicts test

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37
Q

give the 5 steps of testing with sugars

A

1) prep food sample, and transfer 5 cm cubed to test tube
2) prep a water bath set to 75 degrees C
3) with a pipette drop 10 drops of some benedicts solution to bath
4) place test tube in bath in a test tube holder and leave for 5 mins, making sure tube is pointing away from you
5) if food sample contaisn sugar it will go from blue to trafic light cols

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38
Q

what test is used startch?

A

the iodine test

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39
Q

give the 2 steps of testing for startch?

A

1) make food sample, and transfer 5cm cubed to test tube
2) add afew drops of iodine solution and gently shake tube to mix contents

if starch is present the col of solution will go from browny-orange to black or blue-black

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40
Q

what test do you use for proteins?

A

the biuret test

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41
Q

give the 3 step method of testing for proteins

A

1) prep sample of food and transfer 2cm cubed to test tube
2) add 2 cm cubed of biuret solution to the sample and mix the contents of the tube by gently shaking it
3) if the food sample contains protein col will go from blue to purple

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42
Q

what test is used for lipids?

A

sudan III

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43
Q

what is the 3 step method for testing for lipids?

A

1) prep sample ( no need to filter) transfer 5cm cubed into test tube
2) use pipette to add 3 drops of Sudan III stain solution and gently shake tube
3) if lipids are present solution will separate to two layers - top layer will be bright red

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44
Q

the lungs are in what part of the body?

A

the thorax

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45
Q

what kind of membranes are the lungs surrounded by?

A

pleural membranes

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46
Q

describe the journey of air to gas exchange

A

The air that you breathe goes through the trachea, and this splits into two tubes called bronchi, one going to each lung. The bronchi split into progressively smaller tubes called bronchioles. The bronchioles end at small bags called alveoli, where the gas exchange takes place.

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47
Q

describe the blood passing next to the alveoli before gas exchange

A

it has just returned to the lungs from the rest of the body, contains lots of carbon dioxide and very little oxygen

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48
Q

describe gas exhange ( in the lungs)

A

Oxygen diffuses out of the alveolus (where its at a high concentration) into the blood (where its at a low concentration)

Carbon dioxide diffuses out of the blood (where its at a high concentration) and into the alveolus (where its at a low concentration ) it is now ready to be breathed out

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49
Q

describe gas exhange (in body cells)

A

when blood reaches body cells the red blood cells release oxygen (high conc) and diffuses into body cells (low conc)

simultaneously, carbond dioxide diffuses out of the body cells (where there is a high conc) and into the bllod (low conc) it is then carried back to the lungs

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50
Q

describe what is meant by “the double circulatory system”

A

The circulatory system is made ip of 2 circuits joined together:

1st - reight ventricel pumps deoxygenated blood to the lungs to take in oxygen, the blood then returns to the heart

2nd - left ventricle pumps oxygenated blood around all the other organs of the body. The blood gives up its oxygen at the body cells abd the deoxygenated blood returns to the heart to be pumped out to the lungs again

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51
Q

what are the walls of the heart mostly made of?

A

muscle tissue

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52
Q

why does the heart have valves?

A

to make sure that blood flows in the right direction, not backwards#

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53
Q

what are the 4 heart chambers?

A

right atrium, right ventricle, left atrium and left ventricle

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54
Q

describe blood flow in 5 steps

A

1) blood flows into the 2 atria from the vena cava and the plumonary vein
2) the atria contract pushing the blood into the ventricles
3) the ventricles contract forcing the blood into the plumonary artery and the aorta and out of the heart
4) the blood then flows to the organs through the arteries and returns through veins
5) the atria will fill again and the whole cycle will start over

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55
Q

what is the purpose of the coronary arteries?

A

providing the heart with its own supply of oxygenated blood

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56
Q

describe the hearts natural pacemaker?

A

a group of cells in the right atrium which produce a small electrical impulse which spreads to the surrounding muscle cells, causing them to contract

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57
Q

what can be used if a patient has an irregular heartbeat?

A

an artifical pacemaker - a little device that is implanted under the skin and has a wire going to the heart. it produces an electric current to keep the heart beating regularly

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58
Q

what do arteries do?

A

carry blood away from the heart

59
Q

what do capillaries do?

A

they are involved in the exchange of materials at the tissues

60
Q

what do veins do?

A

carry blood to the heart

61
Q

describe the arteries

A
  • heart pumps blood out at high pressure, so they are strong and elastic
  • the walls are thick compared to the size of the lumen
  • contain thick layers of muscle for strenth and elastic fibres which allow them to stretch and spring back
62
Q

describe the capillaries

A
  • arteries branch into capillaries, they are very tiny
  • carry blood really close to every cell in the body to exchange substances with them
  • have permebale walls, so substances can diffuse in and out
  • supply food and oxygen and take away waste like CO2
  • usually only 1 cell thick
63
Q

describe veins

A
  • capillaries join up to form veins
  • blood at lower pressure, so walls aren’t as thick as arterty walls
  • bigger lumen to help blood flow despite the lower pressure
  • have valves to help blood flow in right direction
64
Q

rate of blood flow =

A

volume of blood/ number of minutes

65
Q

give 2 ways white blood cells can defend against infection:

A

1) phagosytosis - englufing the microrganism by changing shape
2) producing antibodies to fight microrganisms, and antitoxins eto neutralise any toxins producede by microrganisms

66
Q

what is coronary heart disease?

A

when the coronary arteries get blocked by the build up of fatty deposits leading to narrowing of the arteries, which causes the blood flow to be restricted, and the lack of oxygen getting tot he heart can result in a heart attack

67
Q

what are stents?

A

tubes inserted insude arteries which keep them open making sure blood can pass through to the heart muscles, which keeps the persons heart beating

68
Q

what are the positives and negatives of stents?

A

positives:

  • lowers risk of heart attack in person with coronary heart disease
  • effective for a long time
  • recovery time after surgery is relatively quick

negtaives:
- risk of complications during operation
- risk of infection from surgery
- risk of thrombosis (blood clot developing near stent)

69
Q

Too much LDL cholestrol in a persons bloodstream can lead to…

A

build up of fatty deposits in arteries, leading to coronary heart disease

70
Q

what are statins?

A

drugs that reduce the amount of LDL cholestrol present in the bloodstream

71
Q

what are the advantages of statins?

A
  • reducing the amount of LDL cholestrol reduced the risk of strokes, coronary heart disease and heart attacks
  • increases HDL cholestrol in blood, a beneficial type, which can help remove LDL from blood
  • some studies have suggested they may also help preevnt some other diseases
72
Q

what are the disadvantages of statins?

A
  • long term that must be taken regularly, thre is a risk someone could forget to take them
  • can cause sideffects (headaches, kidney failure, liver damage and memory loss)
  • effect isn’t instant, takes time for their effect to kick in
73
Q

if a patient has heart failure, what options may a doctor consider?

A
  • heart transplant if a suitable donor organ is avaliable, and procedure is appropriate
  • an artificial heart
74
Q

what are artificial hearts, and what are they used for?

A

mechanical devices that pump blood for a person whose own heart has failed. They are usually a temporary fix to keep a person alive while a donor heart can be found, or to help a person recover by allowing the heart to rest and heal

75
Q

what is the advantage of an artificial heart?

A

they are less likleu to e rejected by the bodys immune system, than a donor heart. This is because they are made from metals and plastics, so the body does not recognise them as foreign and tries to attack them as they would with a living tissue

76
Q

what are the disadvantages of artifical hearts?

A
  • surgery to fit one can lead to infection and bleeding
  • don’t work as well as natural ones, parts could wear out or electrical motor could fail
  • blood dosen’t flow through as smoothly , which can cause blood clots, and consequently strokes
  • patients has to take blood thinning drugs, which could cause complications with bleeding if they are hurt in an accident
77
Q

whaht damages heart valves?

A

heart attacks, infection or old age

78
Q

what can happen when heart valves become damaged?

A

valve tissue may stiffen, so it won’t open properly, or it may become leaky allowing blood to flow in both directions, and consequently the blood dosen’t circulate as efficently as normal

79
Q

how can severe valve damage be treated?

A

by replacing the valve withe ethier biological valves, or mechanical valves

(less drastic than heart transplant, but still major surgery and risk of blood clots)

80
Q

what is artifical blood?

A

a blood subsitute (eg a saline solution) which is used to replace the lost volume of blood.It can keep a patient alive even if they have lost 2/3s of their red blood cells, giving the patient more time to produce new ones

81
Q

what happens if the artifical blood cannot give the person enough time to produce new red blood cells?

A

they will need a blood transfusion

82
Q

define health

A

the state of physical and mental wellbeing

83
Q

what is a communicable disease?

A

those that can be spread from person to person, or between animals and people
they are contagious and infectious diseases

84
Q

what are non-communicable diseases?

A

those that cannot spread between people or between animals and people

85
Q

why do people with probelms wth their immune system have an increased chance of suffering from communicable diseases such as influenza?

A

their body is less likleu to be able to defend itself against the pathogen that causes the disease

86
Q

some types of cancers can be triggered by being infected by certain types of …….
(give some examples)

A

hepatitius virus - increased chance of liver cancer

HPV - can cause cervcal cancer in women

87
Q

immune system reactions in the body caused by a pathogen can sometimes trigger alergic reactions such as…

A
  • skin rashes

- worsened astmah symptoms

88
Q

why may a mental health problem, such as depression be truggered if somone is suffereing from severe physical health problems?

A

because it can impact the persons ability to carry out everyday activities, or lower life expectancy

89
Q

what factors, other than disease can affect your health?

A
  • lifestyle
  • life situation
  • diet
  • stress
90
Q

what is a risk factor for disease?

A

Something that is linked to an increased liklihood that a person will develop a disease during their lifetime.

91
Q

give an example of a risk factor that would be an aspect of a persons lifestyle?

A

how much the individual exercises

92
Q

give an example of a risk factor that would be the prescence of a certain substance in the environment?

A

air pollution

93
Q

give an example of a material that would be a risk factor for illness?

A

asbestos fibres ( later life cancer)

94
Q

on what 3 levels do risk factors have impacts?

A

locally, nationally and globally

95
Q

In developed countries what kind of diseases are more prevalent and why?

A

Non-communicable, because people have a higher income and can buy high fat food

96
Q

Nationally, people from deprived areas are more llikley to smoke, have a poor diet, and exercise - how does this impact the national health?

A

There would be a higher incidence of cardiovascular disease, obesity, and type 2 diabetes.

97
Q

what impacts the local incidence of diasease?

A

Your individual choices.

98
Q

Explain what diseases smokung has been proven to directly cause, and why?

A
  • Cardiovascular disease, lung disease, lung cancer

- because it damages the walls of the arteries ance cells in the lining of the lungs

99
Q

It is thought that obesity can directly cause type 2 diabetes, why is this?

A

It makes the body less sensitive or resistant to insulin meaning that it struggles to control the levels of glucose in the body.

100
Q

How can drinking too much alcohol impact human health?

A

It can cause liver disease and affect brain function by damaging the nerve cells in the brain causing it lose volume

101
Q

Doing what 2 things whilst pregnant could cause health probelms for the unborn baby?

A

smoking and drinking alcohol

102
Q

What are carcinogens? give an example.

A

things that can cause cancer

eg. ionising radiation

103
Q

exposure to certain substances or radiation can cause…what?

A

cancer

104
Q

Risk factors are identified by correlations in data, but corellations do not always equal….

A

cause

105
Q

what is the human cost of non-communicable diseases?

A
  • millions of people around the world die per year
  • lower quality life
  • shorter lifespan
  • impact is not just upon the sufferers but loved ones too
106
Q

what is the fiancial cost of non-communicable diseases?

A
  • very expensive for NHS ( and other health organistaions around the world) to research them
  • families may have to move or adapt tehir home
  • if family member gives up job or dies, there will be a lower income
  • reduction in ppl working impacts countires economy
107
Q

what types of cancer is smoking considered a risk factor for?

A

lung, mouth, bowel, stomach and cervical cancer

108
Q

what types of cancer is obesity linked to?

A

bowel, liver and kidney cancer

109
Q

what people are at risk of skin cancer due to UV exposure?

A
  • people often exposed to sun / spend lots of time outside
  • people who live in sunny climates
  • people who frequently use sun beds
110
Q

what kinds of infection puts you at a higher risk of developing kindey cancer?

A

Hepititus B, and Hepititus C

111
Q

Viral infection is a risk factor for cancer, what are some examples of lifestyle choices that increase a persons likelihood of being infected with the virus?

A
  • unprotected sex

- sharing needles

112
Q

describe how genetics can be a risk factor for cancer.

A
  • You may inherit faulty genes which make you more suseptible to cancer
113
Q

mutations in what type of genes have been linked with a higher likelihood of developing breast and ovarian cancer?

A

BRCA

114
Q

give 3 examples of plant organs

A

stems, roots, leaves

115
Q

what are the 5 plant tissues?

A

1) Epidermal tissue
2) palisade mesophyll tissue
3) spongy mesophyll tissue
4) xylem and pholem
5) meristem tissue

116
Q

which tissue covers the whole plant?

A

epidermal tissue

117
Q

In which part of the leaf does the most photosynthesis happen?

A

palaside mesophyll tissue

118
Q

describe the spongy mesophyll tissue

A

in the leaf, contains big air spaces to allow gases to diffuse in and out of cells

119
Q

what is the purpose of the xylem and pholem?

A

to transport things like water, mineral ions and food around the plant

120
Q

where is the meristem tissue found?

what is it able to do?

A
  • tips of shoots and roots

- differentiate into different types of cells allowing the plant to grow

121
Q

what 4 tissues does the leaf contain?

A

epidermal, mesophyll, xylem and pholem

122
Q

why are the epidermal tissues covered in a waxy cuticle?

A

to reduce water loss by evaporation

123
Q

why is the palaside mesophyll tissue layer nearer the top of the leaf?

A

because it has lots of chloroplasts, in which photoshynthesis happens, they need to be near the top of the leaf to get the most light

124
Q

the xylem and pholem form a network of……

A

….. vascular bundles

125
Q

xylem and pholem deliver what to the leaf, and what do they take away?

A

deliver: water and other nutrients

take away: glucose (produced by photosynthesis)

126
Q

how are the tissues adapted for efficent gas exchange?

A
  • lower epidermis full of little holes called stomata, which let CO2 difuse directly into the leaf
  • opening and closing of stomata controlled by guard cells which respond to environmental conditions
  • air spaces in spongy mesophyll tissue increase the rate diffusion of gases
127
Q

what is the purpose of phloem tubes?

A
  • to transport ( in both ways) food substances made in the leaves to the rest of the plant for immediate use or for storage
128
Q

where does translocation happen?

A

in the pholem tubes

129
Q

describe the structure of phloem tubes

A
  • made of columns of elongated living cells with samll pores in the end walls to allow cell sap to flow through
130
Q

what is the purpose of the xylem tubes?

A

to carry water and mineral ions from the roots to the stem and leaves

131
Q

what is the structure of the xylem tubes?

A

made up of dead cells joined end to end with no end walls between them and a hole down the middle

132
Q

what material are xylem tubes strengthend with?

A

ligin

133
Q

what is transpiration caused by?

A

evaporation in the leaf causes there to be a slight water shortage, so more water is drawn up from the rest of the plant through the xylem vessels to replace it, this in turn means more water is drawn up from the roots so there is a constant transpirtaion stream through the plant

134
Q

transpiration is just a side effect of the way leaves are adapted for photosythesis. Explain how this is…

A

They must have stomata so they can exhange gases easily, because there is a higher conc of water inside the plant than the air outside the water escapes from the leaves through the stomata by diffusion.

135
Q

what are the 4 main things the transpiration rate is affected by?

A
  • light intensity
  • temperature
  • air flow
  • humidity
136
Q

how is the transpiration rate affected by light intensity?

why is it affected in this way?

A
  • the brighter the light, the faster the transpiration rate

because the stomata begin to close as it gets darker, because photosynthesis can’t happen in the dark so they don’t need to be open to let Co2 in. When the stomata are closed, very little water can escape

137
Q

how does the temperature affect the transpiration rate?

A

the warmer it is, the faster the transpiration rate

138
Q

how is the transpiration rate affected by air flow?

why is it affected in this way?

A
  • the better the air flow around the leaf the greater the transpiration rate

if the water flow around a leaf is poor the water vapour just surrounds the leaf and soesn’t move away, this means diffusion dosn’t happen as quickly ( smaller conc gradient)
if there is good air flow, water vapour is swept away maintaing a lower conc of water outside the leaf, so diffusion happens quicker

139
Q

how is the transpiration rate affected by humidity?

why is it affected in this way?

A

the drier the air around the leaf the faster the transpiration rate

similar to air flow, if the air is flow there is already quite a bit of water in it already so there is a smaller concentration gradient, and therfore a slower rate of diffusion, and transpiration

140
Q

you can measure the rate of transpiration by measuring the uptake of water by the plant, why?

A

because you can assume the water uptake by the plant is directly related to water loss by the leaves (transpiration)

141
Q

describe guard cells…

A
  • kidney shape that opens and closes the stomata
  • thing outer walls and thickened inner walls making the opening and closing work
  • sensitive to light
  • close at night to save water without losing out on photosynthesis
142
Q

what are guard cells adapted for?

A

gas echange and controlling water loss within a leaf

143
Q

what happens to the guard cells when a plant has lots of water?

A

they will fill up with the water, and go plump which causes the stomata to open so gases can be exchanged for photosynthesis

144
Q

what happens to the guard cells when the plant is short of water?

A

the guard cells become flacid making the stomata close which helpps the plant not loose too much water vapour

GCSE Biology (8 decks)

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