N5 Biology Unit 2 Flashcards
1
Q
What is mitosis?
A
The division of body cells to maintain the chromosome complement.
2
Q
What are chromatids?
A
Part of a double chromosome held together at the centromere.
3
Q
What is the equator?
A
The middle of the cell where chromosomes line up during mitosis.
4
Q
What are spindle fibres?
A
Protein fibres that attach to the centromere and pull the chromatids apart.
5
Q
Why are new cells needed?
A
For growth, repair and to replace damaged or dead cells.
6
Q
What is a chromosome?
A
Found in the nucleus and made of two identical chromatids.
7
Q
What are homologous chromosomes?
A
A pair of chromosomes that match in shape, size and genes.
8
Q
What is the chromosome complement of humans?
A
Two sets or 46 chromosomes.
9
Q
What is the number of chromosomes in human gametes (sperm or egg)?
A
Haploid, 23 or one set of chromosomes.
10
Q
What is the number of chromosomes in a normal diploid body cell?
A
Diploid, 46 or two sets of chromosomes.
11
Q
How many chromosomes are shared from each parent?
A
23 chromosomes (half) from each parent.
12
Q
What are daughter cells?
A
Produced during mitosis - identical to each other and to the parent cell.
13
Q
What are stem cells?
A
Unspecialised cells which can divide to self-renew.
14
Q
What is the hierarchy of cells?
A
Cells - Tissues - Organs - Systems
15
Q
Cells work together to form…
A
Tissues
16
Q
Tissues work together to form…
A
Organs
17
Q
Organs work together to form…
A
Body Systems
18
Q
How do cells differ from each other?
A
In shape, size, number and type of organelles.
19
Q
Give examples of tissues.
A
Nervous tissue and muscle tissue.
20
Q
Give examples of organs.
A
Heart, Lungs, Liver, Stomach or Brain
21
Q
Give examples of organ systems.
A
Digestive system, respiratory system, nervous system or circulatory system.
22
Q
What is a zygote?
A
A fertilised egg.
23
Q
What are the stages of mitosis?
A
- Chromosomes shorten and become visible.
- Spindle fibres pull the chromatids apart.
- Cell membrane and cytoplasm divides.
24
Q
Why are specialised cells important?
A
They can self-renew and differentiate
25
What is the difference between specialised and unspecialised cells?
Unspecialised cell can form any cell type.
Specialised cell can only form the same cell type.
26
What are differentiated cells?
Specialised cells e.g. root hair cell or nerve cell.
27
Define haploid.
A cell containing half the chromosome complement i.e. gametes (sex cells).
28
Define diploid.
Normal body cells containing full chromosome complement
(two sets).
29
What is the Nervous System?
Central Nervous System (CNS) and other nerves.
30
What is the Central Nervous System (CNS)?
The brain and spinal cord.
31
What is the function of nerve cells?
Nerves carry information as electrical impulses.
32
How are stimuli detected?
Receptors in the sense organs detect stimuli and pass this to the CNS.
33
How are responses made?
Information is sent from the CNS to the effectors e.g. muscles or glands (response).
34
What are the different parts of the brain and their function?
Cerebrum (personality, memory, emotions).
Cerebellum (balance and co-ordination).
Medulla (heart rate and breathing rate).
35
What are the different types of neurones (nerve cells)?
1. Sensory Neurone
2. Inter Neurone
3. Motor Neurone
36
What is the function of a sensory neurone?
Carry messages from the receptors (sense organs) to CNS.
37
What is the function of inter neurone?
Connects sensory and motor neurones.
38
What is the function of the motor neurone?
Carries messages from the CNS to the effectors (muscles or glands).
39
What is a synapse?
The gap where two neurones meet.
40
What is a reflex action?
Rapid, automatic and protective responses to damaging/harmful stimuli.
41
What is the endocrine system?
Made up of several endocrine glands which secrete hormones into the bloodstream.
42
What are hormones?
Protein chemical messengers – produced at one site and have an effect at another site.
43
What is the function of human growth hormone?
Produced in the pituitary gland – stimulates growth of the long bones.
44
What is ADH (Anti- Diuretic Hormone)?
A hormone produced in the pituitary gland and controls water reabsorption in the kidneys.
45
What is insulin?
Produced in the pancreas and controls the conversion of glucose in the liver.
46
Where do Hormones have an effect?
Hormones travel through the blood to target tissues with specific receptors.
47
What is homeostasis?
The control of the internal environment e.g. thermoregulation, osmoregulation and blood glucose concentration.
48
What is thermoregulation?
Controlling body temperature to ensure enzymes work at optimum.
49
What is osmoregulation?
Controlling water concentration in the blood to prevent cells swelling and bursting.
50
What is blood glucose concentration?
Controlling blood glucose levels to ensure correct levels for respiration.
51
What is diabetes?
A disease caused by a failure to control blood glucose concentration.
52
What is the function of the pancreas?
An organ with receptors to monitor blood glucose concentration.
53
Which hormones are involved in controlling blood glucose concentration?
Insulin and glucagon.
54
What is glycogen?
An insoluble storage carbohydrate found in the liver.
55
What is sexual reproduction?
The production of new offspring from male and female parents.
56
What is variation?
The differences between members of the same species. It is important for survival.
57
What are the human gametes?
Sex Cells.
Sperm (male) and Egg (female)
58
Name the parts of the male reproductive system.
Testes, penis, sperm duct and sperm.
59
Name the parts of the female reproductive system.
Ovary, oviduct, vagina, uterus and egg.
60
What is fertilisation?
When the nucleus of the sperm fuses with the nucleus of the egg.
61
Name the parts of a flowering plant.
Petals, anther, stigma, ovary, nectary, pollen and ovule.
62
What are the plant gametes called?
Sex Cells
Ovule (female) and pollen (male)
63
What is pollination?
Pollen grains carried by the wind or animals and land on the stigma.
64
Describe fruit formation.
After fertilisation the ovules develop into seeds, and the ovary wall becomes the fruit.
65
Which process leads to variation in offspring?
Sexual reproduction.
66
Describe continuous variation.
A type of variation which ranges between a minimum and maximum value.
67
Describe discrete variation.
A type of variation which has clear cut differences e.g. tongue rolling ability.
68
What is genetics?
The study of inheritance and variation.
69
What is inheritance?
The transmission of genes from generation to generation.
70
Where is genetic information found?
DNA, within chromosomes in the nucleus of cells.
71
What is an allele?
Different forms of the same gene.
72
What is phenotype?
The physical appearance of an organism.
73
What is genotype?
The combination of alleles within an organism.
74
What is the dominant allele?
Characteristic represented by a capital letter. Always shown in phenotype.
75
What is a recessive allele?
Characteristic represented by a lowercase letter. Only shows if homozygous (bb).
76
What does homozygous mean?
Individual with the same alleles e.g. GG.
77
What does heterozygous mean?
Individual with two different alleles e.g. Gg.
78
What is a monohybrid cross?
A genetic cross involving only one characteristic.
79
What is the predicted F2 ratio from a monohybrid cross?
3:1
80
What is sex determination?
Eggs carry X chromosomes only. Sperm carry X or Y chromosomes. The sperm cell determines the sex of a baby.
XX = Female
XY = Male
81
What is a genetic carrier?
A person with one copy of a disease allele by not affected by the disease.
82
Give examples of continuous variation.
Height, weight and handspan.
83
Give examples of discrete variation.
Eye colour, hair colour, and ear lobes.
84
What is a bud?
The site of cell division in plants needed to produce new tissues (e.g. leaves).
85
What is a flower?
Contains the plants reproductive organs.
86
What is a leaf?
Part of a plant. The site of photosynthesis and water loss by transpiration.
87
What is a stem?
Transports water and minerals up the plant.
88
What is a root hair?
Part of a plant where water passes into the root hairs by osmosis.
89
Name the different parts of a leaf.
Upper epidermis, palisade mesophyll, spongy mesophyll, vein (xylem and phloem), lower epidermis, guard cells and stomata.
90
Give examples of plant organs.
Roots, stems and leaves.
91
What is the thin waxy cuticle?
The waterproof outer layer of a leaf– allows light through.
92
What is the thin epidermis?
The protective outer layer of a leaf.
93
What is the function of xylem?
Transports water and minerals from the root to the leaves.
94
What is the function of the phloem?
Transports glucose (sugar) up and down the plant.
95
What are the palisade mesophyll?
Cells containing lots of chloroplasts for photosynthesis.
96
What are the spongy mesophyll?
Cells loosely arranged for gas exchange in a leaf.
97
Why do leaves have a moist air space?
To allow gases to dissolve.
98
What is the function of stoma (stomata)?
To allow carbon dioxide in and oxygen out of leaf.
99
What is the function of the guard cells?
To open and close the stomata.
100
What is transpiration?
The movement of water through the plant from the soil to the air.
101
Which plant structure transports water?
Xylem
102
Which plant structure transports glucose?
Phloem.
103
What effects the transpiration rate?
Wind speed, humidity, temperature and surface area.
104
What is a bubble potometer?
An instrument to measure the rate of water uptake by a leafy shoot.
105
Describe the structure of phloem cells.
Living cell with sieve plates and companion cells.
106
Describe the structure of xylem cells.
Non-living cell (dead), hollow vessels with rings of lignin.
107
What are the components of blood?
Plasma, red blood cells and white blood cells.
108
Describe red blood cells.
Specialised cells to transport oxygen. Biconcave disc shape (increases surface area), no nucleus and contains haemoglobin.
109
What is the function of white blood cells?
Phagocyte and lymphocyte destroy pathogens.
110
What is plasma?
Watery, yellow liquid containing blood cells.
111
What is haemoglobin?
Protein which carries oxygen within Red Blood Cells.
112
What is oxyhaemoglobin?
Formed when oxygen combines with haemoglobin in the lungs.
113
What is a pathogen?
A disease causing microorganism (bacteria, fungus or virus).
114
What is a phagocyte?
A White Blood Cell - carries out phagocytosis by engulfing and digesting pathogens.
115
What is a lymphocyte?
A White Blood Cell – some produce antibodies to destroy pathogens.
116
What are antibodies?
A protein complementary or specific in shape to a particular pathogen.
117
Name the parts of the circulatory system?
Heart, blood vessels and blood.
118
What is the structure and function of an artery?
A blood vessel with thick, muscular walls, narrow central channel and carries blood under high pressure away from the heart.
119
What is the structure and function of a blood capillary?
A blood vessel with thin walls, large surface area and forms networks at tissues and organs to allow efficient exchange of materials.
120
What is the structure and function of a vein?
A blood vessel with thinner walls, wider central channel and carries blood under low pressure back towards the heart.
121
What is the function of the pulmonary artery?
Carries deoxygenated blood from the heart to the lungs.
122
What is the function of the right atrium?
Receives blood from the body.
123
What is the function of the vena cava?
Returns deoxygenated blood from the body to the heart.
124
What is the function of the right ventricle?
Pumps blood to the lungs.
125
What is the function of the aorta?
Carries oxygenated blood at high pressure to the body.
126
What is the function of the pulmonary vein?
Returns oxygenated blood from the lungs to the heart.
127
What is the function of the left atrium?
Receives oxygenated from the lungs.
128
What is the function of the left ventricle?
Pumps oxygenated blood around the body.
129
What is the function of a valve?
Prevents the backflow of blood.
130
What is the function of the coronary artery?
Supplies the heart muscle with oxygenated blood.
131
What is the function of the coronary vein?
Removes deoxygenated blood and wastes from the heart muscle.
132
Describe oxygenated blood.
Blood with a high oxygen concentration.
133
Describe deoxygenated blood.
Blood with a low oxygen concentration.
134
Name the areas for the exchanges of materials in the body.
Lungs for gas exchange.
Villi for food absorption.
135
How are capillaries efficient at the exchange of materials?
Large surface area and thin walls (one cell thick) forming a large network.
136
Why do veins contain valves?
To prevent the backflow of blood.
137
Which vessel carries blood at high pressure?
Arteries.
138
What is the pathway for exhalation of air?
Alveoli - Bronchiole - Bronchi - Trachea -Mouth/Nose
139
What are the alveoli?
The air sacs - site of gas exchange in the lungs.
140
How are the lungs efficient at gas exchange?
Thin lining so gases diffuse quickly.
Large surface area for faster diffusion of gases.
Good blood supply for dense network of blood capillaries for diffusion.
Moist so gases can dissolve.
141
What is digestion?
The breakdown of large, insoluble food molecules into small, soluble molecules by enzymes.
142
How is the small intestine efficient?
Long, folded inner lining with villi to increase the surface area.
Extensive blood supply.
Thin walls.
Lacteal for absorption of fatty acids and glycerol.
143
What are villi?
Finger-like projections in the small intestine for the absorption of food.
144
Why does the left side of the heart have a thicker, muscular wall?
Pumps blood further (around the whole body). Left side pumps a shorter distance (to the lungs).
145
Where are the products of digestion absorbed?
In the small intestine:
Blood Capillary (glucose and amino acids)
Lacteal (fatty acids and glycerol)
146
What are the products of protein digestion?
Amino acids.
147
What are the products of carbohydrate digestion?
Glucose
148
What are the products of fat digestion?
Fatty acids and glycerol.
149
What is the direction of oxygen diffusion in the alveoli?
From the air in the alveoli (High Concentration) into the red blood cells (Low Concentration).
150
What is the direction of carbon dioxide diffusion in the alveoli?
From the blood plasma (High Concentration) into the air of the alveoli (Low Concentration).
151
What is the pathway for inhalation of air?
Nose/Mouth - Trachea - Bronchi - Bronchiole - Alveoli
