Biology B5-B9 Flashcards
(159 cards)
1
Q
What kind of reproduction involves two different sexes?
A
Sexual reproduction
2
Q
What kind of cells are sperm and ovum?
A
Gametes (or sex cells)
3
Q
In humans, what is the male gamete?
A
Sperm
4
Q
In humans, what is the female gamete?
A
Ovum
5
Q
Where are sperm made?
A
The testes
6
Q
Where is the ovum made?
A
The ovaries
7
Q
Which organ stores urine?
A
The bladder
8
Q
What is the function of the sperm cell?
A
To swim to the ovum and fertilise it
9
Q
Give two ways in which a sperm cell is specialised for its function.
A
Tail; lots of mitochondria
10
Q
Why do sperm cells have lots of mitochondria?
A
To release energy for swimming
11
Q
What is the function of the ovum?
A
To be fertilised and provide nutrients for the embryo to grow
12
Q
Why do sperm cells have tails?
A
To help them swim
13
Q
Give two ways in which an ovum is specialised for its function.
A
Very big; changeable cell membrane
14
Q
Why is an ovum so big?
A
Contains a lot of nutrients for the embryo
15
Q
Why do ova have changeable cell membranes?
A
To stop more than one sperm entering
16
Q
What is it called when the sperm and egg nuclei fuse?
A
Fertilisation
17
Q
What is the name of the fertilised egg cell?
A
Zygote
18
Q
Where does fertilisation take place?
A
Oviduct
19
Q
What does the zygote grow into?
A
An embryo/body
20
Q
Where does the zygote become embedded so it can grow?
A
Uterus
21
Q
What is the function of the uterus?
A
To help the embryo/fetus develop
22
Q
What is the function of the uterus lining?
A
To cushion and nourish the fetus
23
Q
Until what point is an unborn human baby called an embryo?
A
8 weeks
24
Q
Between which points is an unborn baby called a fetus?
A
8 weeks to birth
25
Which two things does the umbilical cord connect?
The placenta and the fetus
26
Which two things does the placenta connect?
The mother and the umbilical cord
27
What are the functions of the umbilical cord and placenta?
To pass oxygen and nutrients from the mother to the fetus, and to pass waste from the fetus to the mother
28
What is the name for the time when the baby is growing in the uterus?
Gestation
29
How many days is a menstrual cycle?
Average of 28 days
30
What happens at the start of the menstrual cycle?
Menstruation (loss of blood through the vagina)
31
What happens to the uterus lining during menstruation?
It starts to break down
32
How long does menstruation last?
Average of 5 days
33
What happens to the uterus lining after menstruation?
It starts to grow and thicken
34
What happens in ovulation?
The ovaries release an ovum
35
When in the menstrual cycle does ovulation occur?
Around day 14
36
After ovulation, what happens if fertilisation does not occur?
The uterus lining starts to break down
37
In plants, what are the male sex cells?
Pollen
38
In plants, what are the female sex cells?
Ova
39
Where is the pollen produced?
Anthers
40
Where are plant ova produced?
Ovules
41
In plants, what is the name of the female sex organ that receives the pollen?
The stigma
42
What is pollination?
When pollen lands on a stigma
43
What is produced by the plant when an ovum is pollinated?
A seed or fruit
44
What are the twin main types of pollination?
Insects pollination and wind pollination
45
Why do some plants have brightly coloured flowers?
To attract insects
46
What happens after pollination?
Fertilisation and seed growth
47
What is seed dispersal?
How seeds move away from the parent plant
48
In what five ways can seed dispersal occur?
By wind, eaten by animals, stuck to the outside of animals, by water, explosion
49
What process do plants use to produce their own food?
Photosynthesis
50
What is the pigment that absorbs sunlight inside the leaf
Chlorophyll
51
Which sub-cellular structures in a plant cell carry out photosynthesis?
Chloroplasts
52
What is the word equation for photosynthesis?
Carbon dioxide + water → oxygen + glucose
53
What gas is produced during photosynthesis?
Oxygen
54
What are the two reactants involved in photosynthesis?
Carbon dioxide and water
55
What are the two products involved in photosynthesis?
Oxygen and glucose
56
Give three uses for glucose in a plant.
Respiration, making cell walls and converting to starch for storage
57
What substance is used to test for the presence of starch?
Iodine
58
Name three adaptations of a leaf.
Large surface area, thin and contains chlorophyll
59
Explain why leaves have large surface areas.
To absorb more sunlight
60
Explain why leaves are thin.
To give a short diffusion pathway
61
Explain why leaves have chlorophyll.
To absorb sunlight for photosynthesis
62
Name the five layers of a leaf.
Waxy cuticle, upper epidermis, palisade mesophyll layer, spongy mesophyll layer and lower epidermis
63
What are stomata?
Small gaps on the bottom of leaves
64
In which layer of a leaf are the stomata found?
Lower epidermis
65
What is the function of the stomata?
To allow oxygen to leave and carbon dioxide to enter the leaf
66
What are the guard cells?
Curved cells found on the bottom of leaves
67
What is the function of guard cells?
To open and close the somata
68
What is the waxy cuticle?
A thin layer found on the top surface of the leaf
69
What is the function of the waxy cuticle?
To stop water loss from the leaves
70
Name an adaptation of the palisade mesophyll cells.
Contains lots of chloroplasts
71
Explain why palisade mesophyll cells have lots of chloroplasts.
To absorb more sunlight for photosynthesis
72
What is the purpose of the air spaces in leaves?
To allow gases to diffuse in and out of the leaf
73
Why do all cells respire?
So they can get energy to function
74
What is the word equation for aerobic respiration/
Glucose + oxygen → carbon dioxide + water
75
What do we call the reaction that releases energy from glucose?
Aerobic respiration
76
Why is ‘energy’ not in the equation for respiration?
Because it is not a chemical substance
77
What are the reactants involved in aerobic respiration?
Glucose and oxygen
78
What are the products involved in aerobic respiration?
Carbon dioxide and water
79
Which sub-cellular structures are responsible for respiration?
Mitochondria
80
What is the advantage of aerobic respiration compared with anaerobic respiration?
It releases more energy
81
What is the products of anaerobic respiration in animals?
Lactic acid
82
Which type of respiration does not need oxygen?
Anaerobic respiration
83
What are the products of anaerobic respiration in yeast?
Ethanol and carbon dioxide
84
What is the reactants involved in anaerobic respiration?
Glucose
85
What is fermentation?
Anaerobic respiration in yeast or bacteria
86
What is the word equation for anaerobic respiration in humans?
Glucose → lactic acid
87
What is the word equation for anaerobic respiration in yeast?
Glucose → ethanol + carbon dioxide
88
What is the advantage of anaerobic respiration compared with aerobic respiration?
It is able to happen when there is not enough oxygen for aerobic respiration
89
What is a feeding relationship?
Which organisms eat each other
90
Why do organisms eat each other?
To get nutrients and energy
91
What diagrams do scientists use to show feeding relationships?
Food chains
92
What name is given to organisms that make their own food?
Producers
93
Where do producers get their energy from?
The Sun
94
In a food chain, what name is given to an organism that eats another organism?
Consumer
95
In a food chain, which direction do the arrows point?
From the organism being eaten to the organism eating it
96
In a food chain or web, why do arrows point form the organism being eaten to the organism eating it?
To show the flow of energy
97
What is bioaccumulation?
How toxic materials can build up in a food chain
98
What is interdependence?
How organisms depend on each other for survival
99
What is a food web?
A group of interconnected food chains
100
What name is given to organisms that eat animals?
Predators
101
What name is given to animals that are eaten by other organisms?
Prey
102
What happens to the number of prey if the number of predators increases?
The number of prey decreases as more are eaten
103
What happens to the number of predators if the number of prey decreases?
The number of predators decreases as they starve
104
What is a herbivore?
An animal that eats plants
105
What is a carnivore?
An animal that eats other animals
106
What is an omnivore?
An animal that eats plants and animals
107
What is the ‘population’ of an organism?
The number of that organism in a particular area
108
What is an adaptation?
A way in which an organism suits its environment
109
Why do polar bears have white fur?
Camouflage, so they can hunt prey
110
What adaptations does a polar bear have to stay warm in the Arctic?
Body fat, lots of fur and thick legs
111
What adaptations does a camel have to help it stay cool in the desert?
Thin legs, short hair
112
What is the purpose of a camel’s hump of fat?
To release energy and make water
113
Why do camels have kong eyelashes?
To stop sand going in their eyes
114
How is a cactus adapted to prevent water loss?
Thick waxy layer and swollen stem instead of leaves
115
Why does a cactus have spines?
To stop it being eaten
116
Why does a cactus have shallow but wide roots?
To absorb as much rainwater as possible
117
Why does a cactus have a succulent stem instead of leaves?
To prevent water loss
118
What happens during insect pollination?
An insect carries pollen from one flower to another
119
What is the consequence of insect pollination?
Fertilisation of the ovum by the pollen
120
Why do insects fly from flower to flower?
They are attracted to the flowers’ colour and nectar
121
What can happen to a flower once it is pollinated?
It grows a fruit or seed
122
Which insects are the most common pollinators?
Bees
123
What are the two factors causing bee number to drop?
Use of pesticides and loss of habitat
124
What is the relationship between the number of bees and the number of flowers that can be pollinated?
As the number of bees reduces, the number of flowers pollinated will reduce
125
What is food security?
The ability of all people to have enough food all the time
126
What is a pesticide?
A chemical that kills crop-eating insects
127
Give three ways to help increase bee number.
1. Do not spray persticides
2. Plant more flowers
3. Let grass grow long
128
What is heredity?
The process by which genetic information is transmitted from one generation to another
129
What is DNA?
A genetic code
130
Where is DNA found in a cell?
In the nucleus
131
What is a chromosome?
Long chain of coiled DNA
132
What is a gene?
A section of DNA coding for a protein
133
Name the scientists whom collectively discovered the structure of DNA.
Francis Crick, James Watson, Maurice Wilkins and Rosalind Franklin
134
In biology, what is variation?
Differences between organisms
135
What is genetic variation?
Differences caused by DNA
136
What is environmental variation?
Differences caused by the environment
137
State two examples of genetic variation in humans.
Eye colour and ear lobe shape
138
State two examples of environmental variation in humans.
Scars and tattoos
139
State two examples of variation caused by environmental and genetic variation.
Height, the foods a person likes to eat
140
Some variation can show a range of differences, like height. What name. Is given to this type of variation?
Continuous variation
141
Give two other examples of continuous variation.
Skin colour, weight
142
Some variation is limited to a number of categories, like shoe size or eye colour. What name is given to this type of variation?
Discontinuous variation
143
Give two other examples of discontinuous variation
Blood group, tongue rolling
144
Why are we not genetically identical to our parents?
We inherit half of our DNA from each parent
145
What do animals compete with each other for?
Food, mates, territory
146
What do plants compete with each other for?
Light, water, minerals, space
147
What is an adaptation?
A feature that enables an organism to survive
148
Darwin’s theory of evolution occurs through which process?
Natural selection
149
What is evolution?
A change in inherited characteristics of a population over time
150
What are offspring?
The organisms produced in reproduction
151
What is a species?
Organisms that have similar characteristics and can reproduce with each other to produce fertile offspring
152
What is the main difference between vertebrates and invertebrates?
Vertebrates have a backbone whereas invertebrates do not
153
Name the five classes that vertebrates are classified into.
Mammals, amphibians, birds, fish, and reptiles
154
What is meant by biodiversity?
The range of different species in an area
155
State three things that humans are doing that can harm biodiversity.
Pollution, building cities, deforestation
156
State three things that humans are doing that can improve biodiversity.
Breeding programmes, afforestation, conservation
157
What does it mean if a species is endangered?
It is at serious risk of extinction
158
What does it mean if a species is extinct?
That no more of this species exists
159
State two reasons that could cause organisms to become endangered and extinct.
Introduction of new predators, loss of habitat, competition with better-adapted species
