KS3 biology revision Flashcards
1
Q
After fertilisation where is the embryo implanted?
A
The lining of the uterus
2
Q
What is the life cycle?
A
Zygote, embryo, foetus, baby, toddler, child, adolescent,
adult
3
Q
What does the placenta do?
A
Gets food and oxygen from the mothers blood
4
Q
How does the food and oxygen travel to the foetus?
A
Through blood vessels in the umbilical cord
5
Q
What is the foetus protected by and where is it held?
A
It is protected by amniotic fluid and held in the amnion
6
Q
What happens to boys during puberty?
A
Voices break, hair grows on face and chest and testes they start to produce sperm cells.
7
Q
What happens to girls during puberty?
A
Develop breasts and the menstrual cycle begins.
8
Q
Who/what is pollen carried by?
A
By animals (usually insects) or the wind
9
Q
How is pollen carried?
A
It is carried from the anthers of one flower to the stigma of other
10
Q
What is seed dispersal?
A
The fruits carry the seeds to new areas
11
Q
Define germination
A
The growth of a plant
12
Q
Explain the parts of a dandelion flower
A
Pollen grains, stigma, pollen tube style, ovary, ovule, egg cell
13
Q
Where is the pollen tube in the flower?
A
Down the style of each flower and into the ovule
14
Q
What happens in the ovule of a plant?
A
The male gamete (inside the pollen grain) fertilises and egg cell
15
Q
What does a balanced diet mean?
A
Eating the right amount of different nutrients
16
Q
What are examples of carbohydrates (not actual food) and what are they needed for?
A
Sugars and starch for energy
17
Q
What are proteins needed for?
A
Growth and repair
18
Q
What are examples of lipids (not actual food) and what are they needed for?
A
Fats and oils for energy storage and insulation
19
Q
What are vitamins and minerals needed for?
A
For health
20
Q
What is fibre needed for?
A
To keep intestines clean and working properly
21
Q
What is water needed for?
A
To helps cells hold their shape and to dissolve substances
22
Q
What does too much or too little of nutrition cause and what are some examples?
A
Malnutrition. Obesity and deficiency diseases such as scurvy
23
Q
What is energy measured in?
A
Kilo joules
24
Q
Who needs the most energy?
A
Active people and those who are growing
25
What is the digestive system made up of?
Lots of different organs such as the gut, liver and salivary glands
26
How is food pushed through the gut?
Muscles contract behind the food which squeezes it along.
27
What happens when the food is pushed through the gut?
Nutrients are broken down into small soluble molecules by biological catalysts called enzymes. Soluble nutrients are then absorbed into the blood.
28
What does gut bacteria do?
Helps to break down some foods and produce useful substances such as vitamins.
29
How are proteins digested?
By the enzymes in the stomach and the small intestine.
30
How are vitamins and minerals digested?`
They do not need to be digested as they are already soluble
31
How is fibre digested?
It is not digested but stored as faeces in the rectum and egested (eliminated) by the anus
32
What does the large intestine do?
It removes the water from the undigested food
33
What does the small intestine do?
Digested food is absorbed through the walls which has folds (villi and the microvilli) to increase surface area.
34
What does the cell nuclei contain?`
Genetic information
35
What does the genetic information do?
Controls cells and many characteristics of whole organisms
36
What is hereditary?
Passing genetic information from parents to offspring
37
What happens to genetic information when the offspring is reproduced asexually?
The contain the same genetic information as their parent as there is only one parent, so they are identical.
38
What happens to genetic information when the offspring is reproduced sexually?
They have characteristics from both parents as there are 46 chromosomes and they inherit 23 chromosomes from each parent.
39
What are chromosomes made of?
A molecule of DNA
40
Where is genetic information stored?
Genes (sections of the DNA)
41
What is a shape of the DNA molecule?
Double helix
42
Who and when worked out the shape of DNA?
James Watson and Francis Crick in 1950
43
Who took x-ray pictures of the DNA?
Rosalind Franklin and Maurice Wilkins
44
What is a species?
A group of organisms that reproduce sexually with one another to produce more organisms of the same type
45
What is environmental variation?
the ability of an organism to alter greatly its phenotype depending upon environmental conditions
46
What is genetic variation?
Genetic variation is the difference in DNA among individuals or the differences between populations.
47
What is continuous variation?
Variation that can be spread across a scale e.g height
48
What is discontinuous variation?
Can only have certain values e.g shoe size
49
What is biodiversity?
The variety of plant and animal life in the world or in a particular habitat, a high level of which is usually considered to be important and desirable.
50
Why do we need to preserve biodiversity?
- organisms depend on one another
- areas with greater biodiversity recover faster from disasters
- there are many undiscovered substances in organisms that could be useful to us (for food, medicines)
51
What are the ways of preserving biodiversity?
- Protecting habitats
- Cutting down pollution
- Encouraging farmers to plant a wide variety of crops
52
What does tar in cigarettes do?
It coats the alveoli and then reduces the speed of gas exchange
53
What does tar in cigarettes do in the long term?
It causes the alveoli the break apart (emphysema) which reduces their surface area
54
What damage does carbon monoxide cause in the body from cigarette smoke?
It sticks to haemoglobin in red blood cells and stops them carrying so much oxygen.
55
What does nicotine do to the body?
It makes the arteries narrower
56
What does carbon monoxide do to pregnant women?
Can make them have a premature birth
57
What are the short term affects of alcohol?
Vomiting
58
Give two examples of depressants.
Vodka and heroin
59
Give two examples of stimulants.
Caffeine and ecstasy
60
What do stimulants do?
Increase the speed with which the impulses travel through the nervous system.
61
What do depressants do?
Slow the impulses that travel through the nervous system
62
What does the cytoplasm do?
Where chemical reactions happen
63
What does the nucleus do?
Contains DNA, controls the cell
64
What does the cell membrane do?
Controls what goes in and out of the cell
65
What does the mitochondria do?
Where aerobic respiration happens
66
What features are there in a plant cell?
Cytoplasm, nucleus, cell membrane, mitochondria, cell wall, vacuole, chloroplasts
67
What does the cell wall do?
Made from cellulose fibres and strengthens the cell and supports the plant.
68
What does the vacuole do?
Filled with cell sap to help keep the cell turgid.
69
What does the chloroplast do?
Organelles that contains the green pigment, chlorophyll, which absorbs light energy for photosynthesis. Contains the enzymes needed for photosynthesis
70
What is the word equation of aerobic respiration for humans?
glucose + oxygen → carbon dioxide + water
71
What is the word equation of anaerobic respiration for humans?
glucose → lactic acid + energy released
72
What is the word equation of anaerobic respiration for yeast?
glucose → ethanol + carbon dioxide + energy released
73
What is the word equation for photosynthesis?
(Chlorophyll)
Carbon dioxide+Water = Oxygen+Glucose
(Oxygen)
74
What are examples of specialised cells?
Sperm cell, root hair cell, ciliated cell, nerve cell
75
How are sperm cells adapted for their function?
They have tails that allow them to swim and it is also streamlined body to them to move more quickly.
76
How are root hair cells adapted for their function?
For taking up water and mineral ions by having a large surface area to increase the rate of absorption.
77
How are nerve cells adapted for their function?
They are adapted to carry electrical impulses from one place to another: they have a long fibre (axon) which is insulated by a fatty sheath.
78
How are ciliated cells adapted for their function?
Ciliated cells are adapted in the respiratory tract to form an epithelial lining of coordinated metachronal ciliary activity that provides the propelling force for the transport of mucus along the airways.
79
What is diffusion?
Substances move from a high to a lower concentration down a concentration gradient.
80
What is osmosis?
Water moves from a high to a lower concentration across a partially permeable membrane and down a concentration gradient
81
Why is surface area: volume ratio important for diffusion and osmosis?
By reducing cell size, cells are greatly increasing the surface area to volume ratio which makes diffusion/osmosis much more effective.
82
Define cell
The smallest structural and functional unit of an organism, which is typically microscopic and consists of cytoplasm and a nucleus enclosed in a membrane.
83
Define tissue
A group of cells with a similar structure, organised to carry out specific functions.
84
Define organ
A collection of tissues that structurally form a functional unit specialised to perform a particular function. Your heart, kidneys, and lungs are examples of organs.
85
Define organism
In biology, an organism is any individual contiguous system that embodies the properties of life. It is a synonym for "life form".
86
Define organ system
An organ system is a group of organs that work together as a biological system to perform one or more functions.
87
Name some organs systems
Nervous system, musculoskeletal system, respiratory system, reproductive system, digestive system
88
What do plant gas exchange go through?
The stomata in their leaves
89
What are stomata and how can they be opened?
Small holes in the leaves that can be opened and closed by guard cells.
90
What happens when the stomata are open?
Gases can diffuse between the outside of the leaf and the inside spaces of the leaf.
91
Why is the leaf flat?
To give a large surface area to trap light
92
What are palisade cells full of?
Chloroplasts
93
What carries the water throughout the leaf?
Xylem tissue
94
What carries the sugar away from the leaf?
Phloem tissue
95
What exits the leaf through the stomata?
Oxygen and water vapour
96
What enters the leaf through the stomata?
Carbon dioxide
97
How can you measure the force exerted by an antagonist muscle pair as it contracts?
Put a newton meter to the fingers
98
What happens during inhalation?
Muscles in the diaphragm and between the ribs contract. The diaphragm moves down and the ribs move up and outward. This increases the size of the chest and so the pressure inside it drops. Pressure in the lungs is reduced, so atmospheric pressure pushes air in.
99
What happens during exhalation?
Muscles in the diaphragm and between the ribs relax. This reduces the size of the chest and so the pressure inside it rises. Pressure in the lungs is increased, so air is pushed out.
100
What is an air sac made from?
Network of capillaries
101
What are the features of capillaries?
Plasma and red blood cells
102
What was the overall movement of carbon dioxide in capillaries?
Out of the capillaries
103
What was the overall movement of oxygen in capillaries?
Into the capillaries
104
What are the features of the male reproductive system?
Bladder, glands, urethra, sperm duct, testes, foreskin, scrotum
105
What are the features of the female reproductive system?
Ovaries, oviducts, placenta, umbilical cord, uterus, bladder, cervix, vagina
106
What are the seven life processes? (MRS GREN)
movement, respiration, sensitivity, growth, reproduction, excretion and nutrition
