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Flashcards in BIOLOGY Deck (184)
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1

What does a nucleus do in a cell?

It controls the cell's activities and contains the genetic material for cellular reproduction.

2

What is the function of cytoplasm?

It's where most of the chemical reactions take place in a cell

3

What does the cell membrane do?

It controls what comes in and goes out of a cell.

4

What do mitochondria do?

Sub-cellular structures where aerobic respiration takes place

5

What do ribosomes do?

Ribosomes synthesise proteins

6

What is a cell wall made of?

Cell walls are plants' cells - they are made of cellulose to strengthen the cell.

7

What is the function of chloroplasts?

Chloroplasts - found in plant cells - make glucose (food) for the plant through photosynthesis.

8

Name the two main kinds of cell

Prokaryotic cells (bacterial) Eukaryotic cells (plant, animal, fungal)

9

What are some of the main differences between prokaryotic and eukaryotic cells?

Prokaryotic cells are: Smaller Genetic material is not in a nucleus Genetic material is in a single DNA loop and there may be one or more small rings of DNA called PLASMIDS They do not contain mitochondria or chloroplasts

10

What kind of shapes can bacteria have?

Spherical Spiral Rod Curved rod

11

What are flagella?

Tails on cells to move them around (e.g. sperm cells or bacteria)

12

Explain the nature of plasmids

They are loops of DNA found in bacteria. They can be transferred from one cell to another, allowing bacteria to pass genes around. They are also useful for scientists to insert genes into different bacteria.

13

Define 'resolution' in the context of microscopes

The ability to discern more than one object - e.g., cells can't be seen with the naked eye, but under a microscope, they begin to be 'resolved'.

14

What do electron microscopes do?

They pass electrons through a specimen being 'viewed' giving a much clearer image.

15

What is the formula for calculating magnification?

Magnification = size of image/size of real object

16

What sub cellular structure controls activities in the cell?

Nucleus

17

Where are proteins made in a cell?

On the ribosomes

18

Note three structures found in plant cells that are not found in animal cells

Cell wall Chloroplasts Permanent vacuole

19

What is the function of cell sap?

To support the cell

20

Where is DNA found in bacteria?

Floating plasmids

21

Arrange in order of size (largest to smallest) bacterium, liver cell, nucleus, ribosome

Liver cell Nucleus Bacterium Ribosome

22

What is a micrometre?

 

1x10-6(m)

 

 

23

What is an ecosystem

All the organisms living in a habitat and all the non-living parts of that habitat

So - snails and rocks!

polar bears and ice!

 

24

Define biological competition

Living species trying to get enough resources to survive

25

What is interdependence?

Different species relying on each other for food, shelter, pollnation, seed dispersal...

 

If one species is removed, it can affect the whole community. 

26

Define abiotic

non-living

"a"- as a prefix means "without" in Greek

27

Define biotic

"Living"

bios in Greek means life.

28

Define four abiotic factors that affect living communities

light intensity

temperature

moisture levels

soil pH and mineral content

wind intensity and direction

C02 levels for plants

O2 levels for animals

29

Define three biotic factors that can affect a habitat

Changes in food availability

Change in number of predators

Introduction of pathogens/diseases

One species outcompeting another

30

How does a biologist define a population

A group of organisms of one species living in a habitat

31

What are "adaptations"?

Features that organism have that enable them to survive in their normal conditions

32

33

What are extremophiles?

Organisms that live in extreme conditions

- temperature

- pressure

 - salt concentrations

 

Eg. bacteria living on glaciers or near deep sea vents

34

What is a transect line used for?

A line placed across a field on which a quadrat is placed to count species etc

35

What is a stable community to a biologist?

All species and environment factors are in balance so relevant population numbers are stable

36

Describe a chromosome

The nucleus of a cell contains chromosomes made of DNA

Each chromosome carries hundreds of genes.

In body cells, chromosomes are found in pairs with one chromosome coming from each parent.

 

Humans have 23 pairs,

Dogs have 30 pairs.

37

Describe genes

Genes contain the code to make different proteins and so control the development of different characteristics.

 

38

Describe the cell cycle

DNA is copied and new chromosomes are made

Cell undergoes mitosis

Each cell grows and makes new sub-cellular structures

DNA is copied...

39

Describe mitosis

A cell grows and increases the number of sub-cellular structures (ribosomes, mitochondria)

 

The DNA replicates to form two copies of each chromosome

 

During mitosis:

one set of chromosomes is pulled to each end of the cell

the nucleus divides

the cytoplasm and cell memberanes split to form identical cells

40

Why is mitosis important?

It makes new cells for the organism

- growth

- repair

- asexual reproduction

41

What are stem cells?

Undifferentiated cells 

- they have not yet become 'specialised'

They are found in embryos, umbilical cords (embryonic stem cells),

and some organs and tissues (adult stem cells)

42

What are stem cells used for?

- treating conditions where cells are damaged (paralysis, diabetes)

-replace damaged cells

 

43

What is therapeutic cloning?

Use of patient's own stem cells for replacing damaged cells/tissues

- no risk of rejection

 

44

What are meristems and why may they be useful?

Special areas in plants that house their stem cells

- easy for cloning the plant

- help clone nearly extinct species

GM crops bred to resist disease

45

Define (cellular) diffusion

Why does it happen?

The net movement of particules across cell membranes from an area of high concentration to an area of low concentration

 

Because particles move randomly an spread out

 

E.g., O2 and CO2 

Urea from cells into blood

DIgested food molecules into blood

 

46

What factors affect (cellular) diffusion?

Concentration gradient

 

Temperature

(think particle theory - more energy, more movement)

 

Surface area of the membrane

 

*Unicellular organisms have large surface area to volume ratio allowing molecules to easily diffuse

*Multicellular organisms have low surface area to volume ratio, so they have developed specialised cells to help with diffusion: e.g, small intestines, lungs - large surface area, moist.

 

 

47

What maintains the concentration gradient in animals?

Rich blood supply

48

What speeds up gaseous exchange in plants

(i.e., keeps the concentration gradient diffusion working?)

Ventilation

49

Define osmosis

The diffusion of water from a dilute solutoin to a concentrated solution through a semipermeable membrane

50

Explain (cellular) active transportation

When substances are moved against a concentration gradient

- this requires energy

E.g., mineral ions brought in from the soil into root hair cells

and sugar molecules from the lower concentration in the gut into the blood stream

 

**active transport stops in the absence of oxygen or in the presence of metabolic poisons such as cynanide, arsenic, belladonna, and strychnine

51

What happens when cells differentiate?

- may change shape

- have different sub-cellular structures to assist in its specific functions

52

Name some specialist cells

ANIMAL

Nerve cells

Muscle cells

Red blood cells

PLANT

Root hair cells

53

Draw and name the main parts of a motor neuron

54

Draw an name the main parts of a sperm cell

55

Draw and label the main parts of a muscle cell

56

Describe xylem cells

Arranged end to end, end walls break down to form hollow tubes

Cell walls are strengthened by lignin

57

Describe phloem cells

End walls allow sugars through but support the tubes

Arranged end to end into tubes

58

Compare xylem and phloem cells graphically

59

Draw and label a root hair cell

60

What are enzymes?

(four points)

Biological catalysts that speed up reactions in living organisms.

They are large proteins and have an active site inside a space

Enzymes do specific reactions

And work best at optimum temperatures and pH levels

61

What is tissue?

Group of cells with a similar structure and function

62

What is an organ?

Group of diiferent tissues working together to perform a specific job

E.g. stomach contains muscle tissue, glandular tissues (secrete juices), and epithelial (covering) tissue

63

What is an organ system?

Several organs working together to perform a broader function

E.g., Digestive system contains - mouth, oesophagus, stomach, smaller intestine, larger intestine, rectum and anus - and accessories, liver, gall bladder and pancreas.

64

Define an organism

A collection of organ systems that make up an living entity

65

What is denaturing?

When high temperatures or extreme acidic/alkline levels disrupt enzymes such that they denature (fall apart)

66

What is the "lock and key" theory of enzymes?

A model that explains how enzymes seem to work

- the chemical that reacts is the substrate (the key)

- it fits into the enzymes active site (the lock)

 

Emil Fischer (1894!!)

 

 

67

Name four digestive enzymes and their functions

Protease - breaks down proteins/amino acide: produced in stomach, pancreas and small intestine

Lipase - breaks down fats/oils into fatty acids and glcyerol: produced in pancreas and small intestine

Carbohydrase - breaks down carbohydrates

Amylase - breaks down starches into sugar (maltose): produced in salivary glands and pancrease

 

68

What is bile and where is it made? 

Bile is an alkaline liquid to neutralise stomach acids,

Bile also emulsifies fats to increase their surface area

Both of which enables enzymes to work quicker on them 

It is made in the liver and stored in the gall bladder

69

What is the function of the epidermis on a leaf?

Epidermis - 'top layer of skin' - covers the outer surfaces of the plant for protection

70

What happens in the pallisade mesophyll in a leaf?

It's the main site for photosynthesis

71

What is the function of spongy mesophyll in a leaf?

It has air spaces to all gases to diffuse through the leaf

72

What do xylem vessels do in a leaf?

They transport minerals and water from the roots and also help support the plant.

 

"Reach for the xy..."

 

xy rhymes with sky

73

What do phloem vessels do in a plant?

They transport dissolved sugars through the plant (from leaves downward)

This is called translocation

 

phloe = flow down

 

74

What is meristem tissue in a plant?

Meristem tissue is found at the tips of the roots and shoots where new cells are produced for root growth

75

Is a leaf a plant organ?

Yes

76

What process describes how water enters plant root cells?

Osmosis

77

Through which cells does water evaporate and diffuse out of a plant

Stomata (small pores)

78

What term is used to describe the loss of water from leaves?

transpiration

79

What factors affect transpiration?

  •  Temperature (higher = more transpiration)
  • Wind (faster air flow = higher rate of evaporation)
  • Light (more light, stomata open more)
  • Humidity (increase = less transpiration as concentration gradient for diffusion of water into the air is lower)
  •  

 

80

What is the function of guard cells in a plant?

They open and close stomata

81

 why are stomata closed at night?

They close because carbon dioxide is not needed for photosynthesis, so closing the stigmata reduces water loss. 

82

Explain how guard cells work

  1. When water is plentiful the guard cells take up water and become turgid (swollen).
  2. This causes the stigmata to open.
  3. So gases for photosynthesis are free to move in and out of the stigmata along with water from transpiration. 
  4. BUT when water is scarce losing water makes this tomato change shape and close.
  5. This stops the plants from losing water through transpiration.

 

83

What is translocation?

The movement of food (dissolved sugars) through the phloem tissue in a plant.

84

What is a pathogen?

Microorganisms that cause infectious (communicable) diseases

85

How are pathogens spread?

Direct contact

Water

Air

Vectors (other organisms that carry the pathogen which don't get the disease themselves)

86

How can the spread of infectious diseases be hindered?

  1. Hygiene
  2. Increasing immunity through diet/gut flora (post GCSE answer!)
  3. Destroying vectors
  4. Isolating infected persons
  5. Vaccines (potentially - side effects/increased viral resistance)

 

87

Name some viral diseases

Measles

Human immunodeficiency HIV -> can cause AIDS

Human papilloma virus HPV

Polio

Shingles

Chicken Pox

Common cold

Influenza

Rabies

Hepatitis 

Warts

 

PLANTS

Tobacco mosaic virus (TMV)

88

How do bacterial pathogens affect healthy cells?

They can damage cells directly

or they produce toxins that damage tissues

89

Explain how salmonella is introduced and affects the body

1) It is a bacterial infection  

2) It is ingested from food (chickens, eggs)  that is not cooked properly or prepared unhygienically

3) The bacteria secrete toxins that can cause fever, diarrhoea

*  potential defence: vaccinating chickens. 

90

How is gonorrhea spread and what are its symptoms?

Bacteria transmitted sexually

Thick yellow/green discharge from the vaine/penis  with pain urinating

 

Treated with penicillin but evidence of resistance

Avoidance/protection: abstinence/condoms

 

91

What are protists?

What widespread disease (which calls more people than any other on the planet) is due to protists?

Single celled eukaryotic organisms

 

Malaria

 

The protist uses a specific mosquito which passes it into human blood upon sucking blood.

Malaria causes fever and can be fatal. 

Prevention is with nets around the bed, although it seems that people of African genes have a greater immunity than Europeans say.

 

92

What kind of disease is Rose Black Spot?

It's fungal.

 

Fungal spores are carried on the wind to affect plants. 

The infected leaves develop black spots, turn yellow and drop off early. 

A decrease in foliage causes the plant to not grow as fast as photosythesis is reduced.

Treated with fungicides and burning affected material. 

93

What are pathogens?

Microorganisms that enter the body and cause disease

94

What are communicable diseases?

Diseases that can easily spread

95

What are bacteria?

Very small cells- reproduce rapidly

96

Are viruses cells?

No- they’re 1/100th the size of a bacterium

97

What do viruses do?

Live inside cells, use cells machinery to replicate then burst releasing virus

98

What do viruses do to make you feel ill?

Cell damage

99

What are Protists?

Single celled eukaryotes

100

What are parasites transferred by?

A vector

101

What is hyphae?

A thread like structure of fungi

102

What do hyphae do?

Grow and penetrate human skin and the surface of plants causing disease

103

What are the three ways pathogens can be spread?

Water, Air and Direct Contact

104

Name 3 viral diseases

Measles, HIV and tobacco mosaic virus

105

What are the symptoms of measles?

Red skin rash and signs of a fever

106

How is measles spread?

Droplets- sneezes or cough

107

How is HIV spread?

Sexual contact or bodily fluids (blood)

108

What are the symptoms of HIV?

Flu like symptoms

109

What time of cells does HIV attack?

Immune cells

110

What does TMV affect?

Plants

111

TMV symptoms on a plant?

Mosaic pattern of leaves and discoloured

112

Why can’t TMV infected plant carry out photosynthesis?

Because of the discolouration

113

Name a fungal disease?

Rose black spot

114

What does rose black spot do to plants?

Cause black spots on rose plants and leaves drop off

115

How does rose black spot spread?

Through water or wind

116

Name a diseased cause by a protist?

Malaria

117

What vector carries malaria?

Mosquito

118

How can people be protected from malaria?

Insecticides and mosquito nets

119

Name 2 bacterial diseases

Salmonella and Gonorrhea

120

What is salmonella?

Type of bacteria that causes food poisoning

121

What are the symptoms of salmonella?

Fever ,stomach cramps, vomiting and diarrhoea

122

How can you get salmonella?

Eating food that has been contaminated with salmonella bacteria

123

How is salmonella prevented?

Poultry are given vaccinations against salmonella

124

What is Gonorrhoea?

Sexually transmitted disease

125

Symptoms of Gonorrhoea?

Pain when urinating, thick yellow discharge

126

How is Gonorrhoea prevented?

Antibiotics and barrier methods when having sex (comdoms)

127

4 ways spread of disease can be reduced

Being hygienic, destroying vectors, isolating infected individuals , vaccination

128

The largest organ that helps acts as a barrier is?

Skin

129

What in your nose trap particles that could contain pathogens?

Hair and mucus

130

What does the stomach produce to kill pathogens?

Hydrochloric acid

131

What kicks in if pathogens make it into your body?

Immune system

132

What is the most important part of your immune system?

White blood cells

133

Name 3 ways white blood cells attack invading microbes?

Consuming them(phagocytosis), Producing antibodies, producing antitoxins

134

What are in vaccinations?

Small amounts of dead or inactive pathogens

135

What does the MMR vaccine contain?

Measles, mumps and rubella

136

Pros of a vaccine

Control lots of diseases that were common, prevents epidemics

137

Cons of a vaccine

Don’t always work, can have a bad reaction

138

What drug relieves pain?

Pain killers (aspirin, paracetamol)

139

What kills bacteria?

Antibiotics

140

2 ways bacteria could be resistant to antibiotics

Bacteria mutate or if you have an infection

141

What are the resistant bacteria called?

Resistant strain

142

What can the resistant strain do to the body?

Cause a serious infection that can’t be treated by antibiotics

143

How can doctors slow down the rate of resistant strains?

Not to over prescribe antibiotics

144

Name the drug that comes from willow

Aspirin

145

Name the drug that comes from foxgloves

Digitalis

146

Who discovered penicillin

Alexander Fleming

147

Three stages of drug testing

Human cells and tissues, 2 live animals, human volunteers in a clinical trial

148

What produces antibodies?

B-lymphocytes

149

What are monoclonal antibodies produced from?

Lots of clones of white blood cells

150

What do tumor cells do?

Divide lots so they can be grown easily

151

B-lymphocytes and tumor cells bind to make what?

Hybridoma cell

152

What do hybridoma produce?

Monoclonal antibodies

153

What are monoclonal antibodies useful?

They target a specific cell

154

Name something monoclonal antibodies are used in?

Pregnancy tests , treat diseases (cancer), research (measure hormone levels)

155

Side effects of monoclonal antibodies?

Fever, vomiting and low blood pressure

156

3 diseases plants get?

Bacterial, viral and fungal

157

Signs a plant has a disease

Stunted growth, spots on leaves, patches of decay, abnormal growth, malformed stems, discolouration

158

How can you identify a plants disease?

Gardening manual or internet, taking to a laboratory, testing kits

159

What are plants physical defences

Waxy Cuticle, cell walls (contain cellulose), dead cells around stems

160

What are plants chemical defences?

Antibacterial chemicals (mint plant and witch hazel), produce poisons (deadly nightshade and foxglove)

161

What are plants mechanical defences?

Thorns and hairs, leaves that droop or curl, plants mimic other organisms (ice plant family- look like stones)

162

which side of the heart does de-oxygenated blood enter?

the right side

163

what if the heart mainly made of?

muscle tissue

164

how does the heart keep the blood flowing in the right direction?

valves to stop back flow

165

through which artery does oxygenated blood leave?

aorta

166

how do muscles in the heart keep your resting heart rate controlled?

producing electrical impulses which spread through the heart causing them to contract

167

what are two features of an artery?

1. walls are strong and elastic so it can cope with high pressure 2. thick walls compared to the lumen

168

what are two features of a capillary?

1.permiable walls so substances can diffuse in and out 2. supply cells with food and oxygen and take away waste like CO2

169

what are three features of a vein?

1. thin walls because blood at lower pressure 2. large lumento help blood flow 3. valves to keep blood flowing in right direction

170

what is the main function of red blood cells?

to carry oxygen around the body

171

what is the main function of white blood cells?

to defend against infection

172

what is the main funtion of platelets?

to help blood clot

173

what is conorary heart disease?

the conorary arterie gets blocked by layers of fatty material building up so less oxygen is supplied to the heart

174

what are stents used for?

tubes inserted inside arteries to keep them open and allow blood to flow

175

what are statins used for?

drugs that reduce amount of 'bad' cholesterol in your bloodstream

176

what procedures can be done if there is a heart faliure?

transplants of the whole heart or valves

177

what can be used when a lot of blood is lost?

artificial blood like a salt solution or a blood transfusion

178

what are non communicable diseases?

diseases that cannot spread between people or animals and people

179

Name three types of non comunicable diseases?

asthma, cancer and coronary heart disease

180

what are 3 factors that can effect your health?

diet, stress and life style choices (including alcohol, drugs, promiscous sex, poverty)

181

what are 4 risk factors that directly cause a disease?

1. smoking 2.obesity 3.alcohol 4.exposure to certain radiation

182

what causes cancer?

uncontrolled cell growth and division which forms a tumour

183

what are two types of cancer?

1.benign- stays in one place and isnt cancerous 2. malignant-tumour grows and spreads to neighbouring tissues, cancerous

184