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Biology Flashcards

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Biology 101 flashcards
1
Q

What do most human and animal cells have

A 
A nucleus 
Cytoplasm 
A cell membrane 
Mitochondria 
Ribosomes
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2
Q

What is the function of a nucleus

A

To control the activities of the cell

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3
Q

What happens in the cytoplasm

A

Most chemical reactions take place

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4
Q

What is the function of a cell membrane

A

To control the passage of substances into and out of the cell

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5
Q

What is the function of mitochondria

A

To release energy from respiration

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6
Q

What is the function of ribosomes

A

Protein synthesis

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7
Q

What do most plant cells have

A 
A nucleus 
Cytoplasm
A cell membrane
Mitochondria
Ribosomes
Chloroplasts 
Cell wall
Vacuole
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8
Q

What is the function of a cell wall

A

To strengthen the cell. It is made of cellulose

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9
Q

What is the function of chloroplasts

A

To absorb light energy to make food (through photosynthesis)

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10
Q

What is a vacuole filled with

A

Cell sap

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11
Q

What does a bacterial cell consist of

A

Cytoplasm
Membrane
Cell wall

The genes are not in a distinct nucleus

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12
Q

What is yeast

A

A single-celled organism

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13
Q

What does a yeast cell consist of

A

A nucleus
Cytoplasm
Cell membrane
Cell wall

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14
Q

Why might cells be specialised

A

To carry out a particular function

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15
Q

What does diffusion allow

A

Dissolved substances to move into and out of cells

Oxygen required for respiration to pass through cell membranes

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16
Q

What is diffusion

A

The spreading of the particles of any substance resulting in a net movement from a region where there is a higher concentration to a region with a lower concentration

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17
Q

When is the rate of diffusion faster

A

When the difference in concentration is greater

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18
Q

What is a tissue

A

A group of cells with similar structure and function

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19
Q

What are some examples of tissues

A

Muscular tissue
Glandular tissue
Epithelial tissue

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20
Q

What can muscular tissue do

A

Contract to bring about movement

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21
Q

What can glandular tissue do

A

Produce substances such as enzymes and hormones

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22
Q

What can epithelial tissue do

A

Cover some parts of the body

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23
Q

What are organs made of

A

Tissues. One organ may contain several tissues

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24
Q

What does the stomach contain

A

Muscular tissues - to churn the contents
Glandular tissue - to produce digestive juices
Epithelial tissue - to cover the inside and outside of the stomach

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25
Q

What are organ systems

A

Groups of organs that perform a particular function

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26
Q

What is the digestive system

A

An organ system in which humans and other mammals exchange substances with the environment

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27
Q

What does the digestive system include

A 
Glands
The stomach
The liver
The small intestine
The large intestine
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28
Q

What do glands do in the digestive systems

A

Glands, such as the pancreas and salivary glands, produce digestive juice

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29
Q

What happens in the stomach and small intestine

A

Digestion occurs

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30
Q

What does the liver do

A

Produce bile

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31
Q

What does the small intestine do

A

Absorb soluble food

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32
Q

What does the large intestine do

A

Absorb water from the undigested food, producing faeces

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33
Q

What do plant organs include

A

Stems, roots and leaves

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34
Q

Examples of plant tissues

A

Epidermal tissues - to cover the plant
Mesophyll - to carry out photosynthesis
Xylem and phloem - to transport substances around the plant

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35
Q

Equation for photosynthesis

A

Carbon dioxide + water (light energy) = glucose +oxygen

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36
Q

What happens during photosynthesis

A

Light energy is absorbed by chlorophyll, found in chloroplasts in plant cells
This energy is used by converting carbon dioxide (from the air) and water (from the soil) into sugar (glucose)
Oxygen is released as a by-product

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37
Q

What limits the rate of photosynthesis

A

Shortage of light
Low temperature
Shortage of carbon dioxide

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38
Q

What factors are enhanced in greenhouses

A

Light intensity
Temperature
Carbon dioxide concentration

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39
Q

What is glucose produced in photosynthesis converted into

A

Insoluble starch for storage in tubers or bulbs - does not affect water balance.
Plant cells also use some for respiration

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40
Q

What is some glucose in plants and algae used for

A

To produce fat or oil for energy storage (could be used as biofuel)
To produce cellulose, which strengthens the cell wall
To produce proteins

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41
Q

How do plants produce proteins

A

Using glucose and nitrate ions that are absorbed from the soil to make amino acids which then form proteins

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42
Q

What are physical factors affecting organisms

A 
Temperature
Availability of nutrients 
Amount of light
Availability of water 
Availability of oxygen and carbon dioxide
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43
Q

How can quantitative data on the distribution of organisms be obtained by

A

Random sampling of quadrats

Sampling along a transect

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44
Q

What are protein molecules made up of

A

Long chains of amino acids. These long chains are folded to produce a specific shape that enables other molecules to fit into the protein.

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45
Q

What do proteins act as

A

Structural components of tissues e.g. muscles
Hormones
Antibodies
Catalysts

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46
Q

What do catalysts do

A

Increase the rate of chemical reactions.

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47
Q

What are enzymes

A

Biological catalysts. They are also proteins

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48
Q

What is vital for the enzyme’s function

A

The shape of an enzyme. High temperatures denature the active site

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49
Q

What do different enzymes work best at

A

Different pH values

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50
Q

What does xylem tissue transport

A

Water

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51
Q

What does phloem tissue transport

A

Food

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52
Q

Where is amylase produced

A

In the salivary glands, the pancreas and the small intestine

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53
Q

What does amylase do

A

Catalyses the breakdown of starch into sugars in the mouth and small intestine

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54
Q

Where is protease produced

A

In the stomach, pancreas and the small intestine

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55
Q

What does protease do

A

Catalyse the breakdown of proteins into amino acids in the stomach and the small intestine

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56
Q

Where do some enzymes work

A

Outside the body

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57
Q

Where are digestive enzymes produced

A

By specialised cells in glands and in the lining of the gut

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58
Q

What do digestive enzymes do

A

Pass out of the cells into the gut where they come into contact with food molecules. They catalyse the breakdown of large molecules into smaller molecules

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59
Q

Where is lipase produced

A

In the pancreas and small intestine

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60
Q

What do lipase enzymes do

A

Catalyse the breakdown of lipids into fatty acids and glycerol in the small intestine

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61
Q

What are lipids

A

Fats and oils

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62
Q

What does the stomach produce

A

Hydrochloric acid. The enzymes in the stomach work most effectively in these acid conditions

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63
Q

What does the liver produce

A

Bile

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64
Q

Where is bile stored

A

In the gall bladder before being released into the small intestine

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65
Q

What does bile do

A

Neutralise the acid that is added to food in the stomach (increases pH). This provides alkaline conditions in which enzymes in the small intestine work most effectively
It also emulsifies fats by breaking down large globules (fat droplets) in smaller ones

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66
Q

What do some microorganisms produce

A

Enzymes that pass out of the cell

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67
Q

What use do enzymes that pass out of cells have in homes

A

They are in biological detergents which may contain protease and lipase. Biological detergents are more effective at low temperatures than other types of detergents

68
Q

What use does protease have in industry

A

Proteases are used to ‘pre-digest’ the protein in some baby foods

69
Q

How are enzymes used in industry

A

To bring about reactions at normal temperatures and pressures that would otherwise require expensive energy-demanding equipment

70
Q

What is the problem with how enzymes are used in industry

A

Most enzymes are denatured at high temperatures
Costly to produce (supply food/O2 and waste removed)
Expensive to control pH within narrow limits

71
Q

What do enzymes control

A

Chemical reactions inside cells

72
Q

What is aerobic respiration

A

Respiration that uses oxygen

73
Q

Which chemical reactions occur during aerobic respiration

A

Reactions that use glucose and oxygen and reactions that release energy

74
Q

What takes place continuously in both plants and animals

A

Aerobic respiration

75
Q

Where do most reactions in aerobic respiration take place

A

Inside mitochondria

76
Q

What is the equation for aerobic respiration

A

Glucose + oxygen = carbon dioxide + water (+ energy)

77
Q

How is energy released during respiration used

A

To build larger molecules from smaller ones
In animals, to enable muscles to contract
In mammals and birds, to maintain a steady body temperature in colder surroundings
In plants, to build up sugars, nitrates and other nutrients into amino acids which are then built up into proteins

78
Q

What happens during exercise

A

The heart rate increases
The rate and depth of breathing increases
Glycogen stored in muscles are converted to glucose for cellular respiration
The flow of oxygenated blood to the muscles increase

79
Q

What do the changes that happen in exercise increase

A

The blood flow to the muscles and so increase the supply of glucose and oxygen and increase the rate of removal of carbon dioxide

80
Q

What do muscles store glucose as

A

Glycogen, which can then be converted back to glucose for use during exercise

81
Q

When is anaerobic respiration used

A

By the muscles when insufficient oxygen is reaching them to obtain energy

82
Q

What is anaerobic respiration

A

The incomplete breakdown of glucose and produces lactic acid

83
Q

What does anaerobic respiration result in and why

A

An oxygen debt that has to be repaid in order to oxidise lactic acid to carbon dioxide and water. This is because the breakdown of glucose is incomplete as much less energy is released than during aerobic respiration

84
Q

When do muscles become fatigued

A

If muscles are subjected to long periods of vigorous activity, ie they stop contracting efficiently

85
Q

What is a cause of muscle fatigue

A

The build up of lactic acid in the muscles

86
Q

How can lactic acid be removed

A

Blood flowing through the muscles

87
Q

How are chromosomes normally found in body cells

A

In pairs

88
Q

How do body cells divide

A

By mitosis

89
Q

What do chromosomes contain

A

Genetic information

90
Q

What happens when a body cell divides by mitosis

A

Copies of the genetic material are made

Then the cell divides once to form two genetically identical body cells

91
Q

When does mitosis occur

A

During growth or to produce replacement cells

92
Q

How many sets of chromosomes do body cells have

A

Two

93
Q

How many sets of chromosomes do gametes have

A

One

94
Q

What is meiosis

A

The type of cell division in which a cell divides to form gametes

95
Q

What happens when a cell divides to form gametes

A

Copies of the genetic information are made

Then the cell divides twice to form four gametes, each with a single set of chromosomes

96
Q

What happens when gametes join at fertilisation

A

A single body cell with new pairs of chromosomes is formed

97
Q

How is a new individual developed after gametes have joined at fertilisation

A

The single body cell repeatedly divides by mitosis

98
Q

At which stage do most types of animal cells differentiate at

A

An early stage whereas many plant cells retain the ability to differentiate throughout life

99
Q

What is cell division mainly restricted to

A

Repair and replacement

100
Q

What are stem cells

A

Cells from human embryos and adult bone marrow

101
Q

What do human stem cells have the ability to do

A

Develop into any kind of human cell

102
Q

What may treatment with stem cells be able to help

A

Conditions such as paralysis

103
Q

What are the cells of the offspring produced by asexual reproduction produced by

A

Mitosis from the parental cells. They contain the same alleles as the parents

104
Q

Why does sexual reproduction give rise to variation

A

Because when gametes fuse, one of each pair of alleles comes from the parents

105
Q

What determines a person’s sex

A

One of the 23 pairs of chromosomes that carries the genes

106
Q

In what gender are the sex chromosomes the same

A

Female (XX)

107
Q

In what gender are the sex chromosomes different

A

Male (XY)

108
Q

What are some characteristics controlled by

A

A single gene

109
Q

What is an allele

A

A different form of a gene

110
Q

What is a dominant allele

A

An allele that controls the development of a characteristic when its present in only one of the chromosomes

111
Q

What is a recessive allele

A

An allele that controls the development of characteristics only if the dominant allele is not present

112
Q

What are chromosomes made up of

A

Large molecules of DNA which has a double helix structure

113
Q

What is a gene

A

A small section of DNA

114
Q

What does each gene code for

A

A particular combination of amino acids which make a specific protein

115
Q

Who are the only people who do not have unique DNA

A

Identical twins

116
Q

What is DNA fingerprinting

A

A process used to identify individuals because of their unique DNA

117
Q

What is polydactyly

A

Having extra fingers and/or toes

118
Q

What is polydactyly caused by

A

A dominant allele of a gene and can therefore be passed on by only one parent who has the disorder

119
Q

What is cystic fibrosis

A

A disorder of cell membranes

120
Q

From who must cystic fibrosis be inherited from

A

Both parents

121
Q

What is cystic fibrosis caused by

A

A recessive allele of a gene and can therefore be passed on by parents, neither of whom has the disorder but is a carrier

122
Q

What can embryos be screened for

A

The alleles that cause polydactyly, cystic fibrosis and other genetic disorders

123
Q

Where does evidence for early forms of life come from

A

Fossils

124
Q

What are fossils

A

The ‘remains’ of organisms from many years ago, and are found in rocks.

125
Q

How may fossils be formed

A

From the hard parts of animals that do not decay easily
From parts of organisms that have not decayed because one or more of the conditions needed for decay are absent
When parts of the organism are replaced by other materials as they decay
As preserved traces of organisms, e.g. footprints, burrows and rootlet traces

126
Q

What were many early forms of life

A

Soft-bodied, which means that they have left few traces behind. What traces there were have been mainly destroyed by geological activity

127
Q

What can we learn from fossils

A

How much or how little organisms have changed as life developed on Earth

128
Q

What may extinction be caused by

A

Changes to the environment over geological time
New predators
New diseases
New, more successful, competitors
A single catastrophic event, e.g. volcanic eruption or asteroid collisions
Through the cyclical nature of speciation

129
Q

What do new species arise as a result of

A

Isolation
Genetic variation
Natural selection
Speciation

130
Q

How do new species arise as a result of isolation

A

When two populations of a species become separated e.g. geographically

131
Q

How do new species arise as a result of genetic variation

A

When each population has a wide range of alleles that control their characteristics

132
Q

How do new species arise as a result of natural selection

A

When in each population, the alleles that control the characteristics which help the organisms to survive are selected.

133
Q

How do new species arise as a result of speciation

A

When the populations become so different that successful interbreeding is no longer possible

134
Q

Where can diffusion happen

A

In both solutions and gases - the particles in these substances are free to move about randomly

135
Q

What can diffuse through cell membranes

A

Very small molecules - oxygen, glucose, amino acids and water. Big molecules such as starch and proteins cannot fit

136
Q

How are palisade leaf cells adapted for photosynthesis

A

Several chloroplasts at the top of the cell so they’re nearer the light (more photosynthesis)
Tall shape = more surface area = more C02 absorbed from the air
Thin shape = several packed at the top of leaf

137
Q

How are guard cells adapted to open and close pores

A

Special kidney shape - opens and closes stomata
When the plant is full of water, the guard cell fills up and goes turgid. This makes the stomata open so gases can be exchanged for photosynthesis
When the plant is short of water, the cells lose water and go flaccid so the stomata closes - stops water vapour escaping
Thin outer walls and thick inner wall - why the opening and closing works
Sensitive to light and close at night - saves water and does not lose out on photosynthesis

138
Q

How are red blood cells adapted to carry oxygen

A

Concave shape - big surface area - absorbs more oxygen. Also helps to pass smoothly through capillaries to reach body cells
Packed with haemoglobin
No nucleus - more space for haemoglobin

139
Q

What is haemoglobin

A

The pigment that absorbs the oxygen

140
Q

How are sperm and egg cells specialised for reproduction

A

Egg cell contains larger food reserves to feed the embryo
After they fuse the egg’s membrane changes so no more sperm can get in - offspring end up with the right amount of DNA
Sperm cell has long tail and streamlined head - swim
Sperm cell has a lot of mitochondria - provide it with energy
Sperm cell carries enzymes to digest egg cell membrane

141
Q

What is differentiation

A

The process by which cells become specialised for a particular function

142
Q

When does differentiation occur

A

During the development of a multicellular organism

143
Q

Why do large multicellular organisms have different systems inside them

A

For exchanging and transporting materials

144
Q

Structure of a leaf

A 
Waxy cuticle 
Upper epidermis 
Palisade mesophyll 
Spongy mesophyll 
Lower epidermis
145
Q

How does a greenhouse affect the rate of photosynthesis

A

Creates a warm atmosphere
Increases the rate of photosynthesis
Plants grow faster
Can grow fruits unsuitable for British climate

146
Q

How to increase the rate of photosynthesis in greenhouses

A

Using paraffin lamps - produces CO2 and increases temperature
Use artificial light - photosynthesis can continue beyond daylight hours
Add fertiliser to the soil

147
Q

What is hydroponics

A

Growing plants in water with the right balance of mineral ions

148
Q

What is aquaponics

A

Growing plants in water with fish - mineral ions obtained from fish faeces

149
Q

What is osmosis

A

Diffusion of water molecules

150
Q

How can plants adapt to survive in low light levels

A

Increasing surface area of leaves and increasing the number of chloroplasts

151
Q

How can plants prevent water loss

A

No leaves - prevents water loss through transpiration

Smaller surface area of leaves

152
Q

What is quantitative sampling used to do

A

Compare the distribution of the same organism in different habitats
Measure changes in the distribution of an organism over time

153
Q

Why are transects useful

A

Identifies impact of changes in physical factors on organism distribution

154
Q

What is a substrate

A

A molecule on which an enzyme acts in a biochemical reaction

155
Q

What is an active site

A

An area on the enzyme molecule to which the substrate attaches to during the reaction

156
Q

Why does increasing the temperature increase the rate of enzyme activity until the optimum temperature is reached

A

Substrate molecules broken down faster -> more kinetic energy -> more successful collisions

157
Q

What is the route of food through the digestive system

A 
Mouth 
Oesophagus 
Stomach 
Small Intestine 
Large Intestine 
Rectum 
Anus
158
Q

What does digestion do

A

Convert large, insoluble food molecules into small molecules that can be absorbed

159
Q

Why does lipase decrease pH

A

Increases in fatty acids (product from lipid digestion)

160
Q

Adaptations of stomach for enzymes

A

Glands in lining of stomach -> secretes protease enzymes to digest protein
HCl acid produced in stomach -> Ideal environment for enzymes to work effectively and kills most bacteria
Thick layer of mucus -> protects stomach walls against digestion by enzymes and acid

161
Q

Advantages of using enzymes in industry

A

Processes using enzymes are usually cheap to run
Work at low to normal pressures
Catalyses reactions at low temperatures

162
Q

What use does carbohydrase have in industry

A

Carbohydrases are used to convert starch into sugar syrup
Used in processed food productions
Cheap source to sweeten food
Makes fuel (ethanol) from plants

163
Q

What use does enzymes have when slimming

A

Isomerase is used to convert glucose syrup into fructose syrup, which is much sweeter and therefore can be used in smaller quantities in slimming food

164
Q

Why is there an increased breathing rate during exercise

A

Compensate for oxygen being lost
Remove CO2 faster
More O2 -> break down glucose -> respiration gives cells energy -> muscles keep working

165
Q

Why is there an increased heart rate during exercise

A

The heart needs to pump faster to circulate the oxygen and glucose to the cells needed and get rid of the CO2

166
Q

Why do people get flushed skin during exercise

A

Increased blood flow

Release excess heat - blood vessels dilate (greater surface area and closer to skin’s surface)

167
Q

Why do people sweat during exercise

A

To cool the body down (evaporation) so the enzymes can keep working

Additional Science (3 decks)

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