Science EOY Flashcards
(146 cards)
1
Q
What are nutrients?
A
Food substances that provide the raw materials- carbohydrates, fats, proteins, vitamins, minerals
Nutrients are essential for energy, growth, and maintenance of body functions.
2
Q
What are carbohydrates?
A
Starch and sugars
Carbohydrates are the body’s main source of energy.
3
Q
What are fats?
A
Liquid fats are oils. Fats and oils are called lipids.
Fats serve as another source of energy and are stored in the body.
4
Q
What is fiber?
A
Made of plant cell walls- not used by the body. Helps food move through the intestines and stops them getting blocked.
5
Q
What do food labels show?
A
The amounts of different nutrients in food.
6
Q
How can you test for starch in food?
A
Add 2 drops of iodine. If it turns blue-black, starch is present.
7
Q
How can you test for protein in food?
A
Add 5 drops of biuret solution. If it turns purple, protein is present.
8
Q
How can you test for fats in food?
A
Rub on some white paper and hold up to the light. Fats will leave a greasy mark.
9
Q
What is the main source of energy for the body?
A
Carbohydrates
Common sources include bread, potatoes, and pasta.
10
Q
What is the function of fats in the body?
A
Another source of energy that is stored in your body. Some is stored under the skin to insulate the body.
Common sources include dairy products and fried food.
11
Q
What are kilojoules (kJ)?
A
The units for measuring the energy in food.
12
Q
What is respiration?
A
The process that releases energy from food.
13
Q
What pysical factors influence energy needs?
A
Depends on age, sex, and how active you are.
14
Q
What are the uses of proteins in the body?
A
Make new cells allowing us to grow and repair our bodies.
Common sources include meat, fish, cheese, beans, and milk.
15
Q
What are vitamins and minerals used for?
A
Used in small amounts to maintain health.
16
Q
What is calcium needed for?
A
Needed to make bones.
17
Q
What is iron necessary for?
A
Makes red blood cells.
18
Q
What is a balanced diet?
A
Eating a range of foods in the right amounts.
19
Q
What is malnutrition?
A
Having too much / too little of a nutrient in your diet.
20
Q
What is a deficiency disease?
A
Caused by lacking certain nutrients for a long time.
21
Q
What is a heart attack caused by?
A
Fat clogs arteries so little blood reaches the heart.
22
Q
What are reference intakes?
A
How much of each nutrient should be eaten in a day.
23
Q
What is digestion?
A
Turning large insoluble molecules into small soluble ones.
24
Q
What role do teeth play in digestion?
A
Teeth grind food and saliva helps digest food.
25
What occurs in the small intestine?
More digestive juices are added- small digested molecules absorbed into the body.
26
What is the function of the large intestine?
Water is removed from undigested food- faeces formed.
27
What are enzymes?
Substances that speed up the breaking down of large molecules- biological catalysts.
28
What is diffusion?
Movement of particles from an area of high concentration to low concentration.
29
What effect does alcohol have on digestion?
Causes fewer digestive enzymes to be released and can damage villi.
30
What is temperature?
How hot or cold an object is.
## Footnote
Measured in degrees Celsius (°C)
31
What is internal / thermal energy?
The energy stored in the movement of particles.
## Footnote
Measured in Joules (J)
32
What factors affect the amount of internal energy stored?
* Temperature
* Material
* Mass
33
Energy transfer always occurs from a _______ object to a _______ one.
[hotter] [cooler]
34
What is evaporation?
When a liquid turns into a gas. A way of transferring energy.
35
Describe cooling by evaporation.
The fastest moving particles escape a liquid to form a gas, lowering the temperature of the remaining liquid.
36
What are the ways energy can be transferred?
* Evaporation
* Conduction
* Convection
* Radiation
37
What is radiation in terms of energy transfer?
A way of transferring energy by heating through waves (it does not need a medium).
38
What does it mean to emit radiation?
All things give out (emit) infrared radiation; the hotter it is, the more it emits.
39
What are thermal images?
Instruments that measure infrared radiation and convert it into maps of temperatures.
40
What happens to particles in a solid when it is heated?
The particles vibrate more and these vibrations are passed through the solid, transferring energy.
41
What are thermal conductors?
Materials through which energy is transferred easily, such as metals.
42
What are thermal insulators?
Materials through which energy is not transferred easily, such as wood and plastic.
43
Explain convection.
In fluids, when part of it is heated, it becomes less dense and rises, forming a convection current.
44
How are houses kept warm in cold climates?
By burning fuel for heating and insulating houses to keep warmth inside.
45
What are good insulators?
* Brick
* Wood
* Carpet
* Feathers
* Wool
46
Why is air considered a poor conductor?
Because the particles are far apart.
47
How are houses kept cool in hot climates?
By painting them white to reflect infrared radiation.
48
Why are solar panels painted black?
Because dark colours absorb and emit infrared radiation well.
49
What is a vacuum flask designed to do?
Reduce energy transfers and keep contents hot.
50
What features of a vacuum flask help reduce energy transfers?
* Plastic stopper to stop convection
* Glass walls with silver coating to reflect radiation
* Vacuum between walls to prevent conduction or convection
51
What is power?
The amount of energy transferred by an appliance per second.
52
What are the units for measuring power?
Watts (W)
53
What is the equivalent of 1000W in kilowatts?
1kW (kilowatt)
54
What do power ratings tell us?
How much energy an appliance transfers.
55
What is efficiency?
The amount of useful energy transferred by a device compared with the amount of energy supplied to it.
56
What is a Sankey diagram?
A diagram that represents energy transfers.
57
What is a kilowatt-hour (kWh)?
The amount of energy transferred in 1 hour by an appliance.
58
Why do energy companies use kilowatt-hours?
To measure energy use.
59
How can one save money on electricity or gas bills?
By not using as much energy; insulating houses and using more efficient appliances help.
60
What is payback time?
How long it will take to save the money that an efficiency measure costs.
61
What is an astronomer?
A scientist that studies space.
62
What could early astronomers use to make observations?
Their eyes.
63
Who proposed the Earth-centered model of the solar system?
Ptolemy.
64
What years did Ptolemy live?
90-168.
65
Who suggested that the Earth and other planets orbit the Sun?
Nicolaus Copernicus.
66
What years did Nicolaus Copernicus live?
1473-1543.
67
What was the initial reaction to Copernicus’ model?
It was not accepted straight away.
68
Who provided further evidence to support Copernicus' model?
Galileo.
69
What model did Johannes Kepler propose?
The Sun is at the center with planets moving in elliptical orbits.
70
What years did Johannes Kepler live?
1571-1630.
71
What causes the phases of the Moon?
The Moon's position relative to the Earth and Sun.
72
What role do spacecraft play in space exploration?
They collect samples and take readings on other planets.
73
What characterizes summer?
Longer days than nights, Sun high in the sky.
74
What characterizes winter?
Longer nights than days, Sun not very high in the sky.
75
What causes the seasons on Earth?
The tilt of the Earth’s axis by 23.5 degrees.
76
What happens when the northern hemisphere is tilted towards the Sun?
It is summer in the UK.
77
What happens when the northern hemisphere is tilted away from the Sun?
It is winter in the UK.
78
What is a compass?
A magnet that points north.
79
What is the north-seeking pole of a magnet?
The end of a bar magnet that points north.
80
What is the south-seeking pole of a magnet?
The end of a bar magnet that points south.
81
What does it mean when two magnets attract?
They are pulled together.
82
What does it mean when two magnets repel?
They are pushed apart.
83
What is a magnetic field?
The area around a magnet where it has an effect.
84
Where is the magnetic field strongest?
Closest to each pole.
85
In what direction does a magnetic field run?
From the north pole towards the south pole.
86
What is gravity?
The force exerted by all objects with mass trying to pull other objects towards it.
87
How does mass affect gravity?
The bigger the mass, the stronger the force it exerts.
88
What is weight?
The force of gravity pulling on you.
89
In what units is weight measured?
Newtons (N).
90
What is a gravitational field?
The space around the Earth where gravity attracts things.
91
What is the approximate gravitational field strength at the Earth's surface?
About 10 newtons per kilogram (N/kg).
92
What is the formula for weight?
Weight = mass x g.
93
What keeps the Earth in its orbit around the Sun?
The force of gravity.
94
What is a satellite?
Anything that orbits a planet.
95
What are natural satellites?
Examples include moons.
96
What are artificial satellites?
Satellites put into orbit for purposes like photographing or transmitting TV programs.
97
What is a constellation?
A pattern of stars.
98
What are stars?
Huge balls of gas that give out large amounts of energy.
99
Why do stars appear less bright than the Sun?
They are further away.
100
What are galaxies?
Large groups of stars.
101
What is the Milky Way?
The galaxy our Sun is in.
102
What is the universe?
Made up of all the millions of galaxies.
103
What is a light year?
A measurement of distance; the distance travelled by light in 1 year.
104
How far is a light year in kilometers?
Approximately ten million million kilometers.
105
What is the nearest star to the Sun?
Proxima Centauri.
106
How far is Proxima Centauri from the Sun?
About 4.22 light years away.
107
Who conducted an experiment with a burning candle in a jar to demonstrate the need for air?
Robert Boyle
## Footnote
Robert Boyle's experiment showed that without air, the candle extinguished.
108
What did Joh Mayow discover about air's role in combustion?
Only a certain part of the air is needed to keep a candle burning and a mouse alive.
109
Which two scientists showed that oxygen is essential for combustion and respiration?
Joseph Priestly and Antoine Lavoisier
110
What percentage of air is made up of oxygen?
21%
111
Define Aerobic Respiration.
Using oxygen to release energy from glucose.
112
What is the word equation for combustion of glucose?
The same as aerobic respiration but occurs differently.
113
What are reactants in a chemical equation?
The starting substances, written on the left.
114
What are products in a chemical equation?
The new substances made, written on the right.
115
What is the role of the diaphragm in breathing?
It contracts/relaxes, changing the size of the lungs.
116
What is inhalation?
Breathing in.
117
What is mucus?
A sticky liquid that traps dirt, dust, and microorganisms.
118
What are cilia?
Tiny hairs on cells that sweep mucus from the lungs.
119
What is gas exchange?
The swapping of gases between the lungs and the blood.
120
Define diffusion.
Movement of particles from a high concentration to low.
121
What are alveoli?
Little pockets in the lungs.
122
What adaptations do alveoli have for gas exchange?
* Increase surface area for faster diffusion
* Walls are one cell thick for faster diffusion.
123
What do red blood cells do?
Take in oxygen when it enters the blood.
124
What is haemoglobin?
The protein where oxygen binds in red blood cells.
125
What are arteries?
Blood vessels that carry blood from the heart to the body.
126
What are capillaries?
Tiny blood vessels where oxygen leaves red blood cells.
127
What is plasma?
The liquid part of the blood that leaks out of capillaries.
128
What is tissue fluid?
Carries oxygen to the cells.
129
What is the function of veins?
Carry blood back towards the heart.
130
How does exercise affect oxygen demand?
Muscles need more oxygen and glucose, increasing breathing and heart rates.
131
What is frostbite?
Condition caused by blood vessels narrowing, reducing blood flow to cells.
132
What causes a heart attack?
Fatty substances building up in blood vessels, reducing blood flow.
133
What is carbon monoxide?
A poisonous gas that binds to haemoglobin, reducing oxygen transport.
134
What is tar in tobacco smoke?
Irritates alveoli and can lead to emphysema.
135
What happens in asthma?
Tiny tubes in lungs narrow and fill with mucus, reducing airflow.
136
What is limewater used for?
Turns cloudy in the presence of carbon dioxide.
137
What does Hydrogen Carbonate Indicator indicate?
Turns from pink to yellow as carbon dioxide increases.
138
How do gills function in gas exchange?
Water flows over gills where oxygen diffuses into the blood.
139
What are stomata?
Tiny holes in leaves that allow gas exchange.
140
Define Anaerobic Respiration.
Respiration occurring in the cytoplasm when oxygen isn’t present.
141
What is the word equation for anaerobic respiration?
Glucose → lactic acid.
142
How does anaerobic respiration compare to aerobic in terms of energy?
Releases less energy than aerobic respiration.
143
What is an advantage of anaerobic respiration?
Allows for a quick, sudden burst of energy.
144
What happens to lactic acid after strenuous exercise?
It is carried to the liver and converted back to glucose.
145
What does EPOC stand for?
Excess post-exercise oxygen consumption.
146
What is EPOC's role after strenuous exercise?
Extra oxygen is needed to replace lost oxygen and convert lactic acid.
