Key Terms

Question 1

Magnification

Answer 1

It’s how large the image is compared to it’s natural size.

Question 2

Resolution

Answer 2

It’s the ability to distinguish between 2 points.

Question 3

General formula for standard index form

Answer 3

-Ax10n

Question 4

Diffusion

Answer 4

The net random movement of particles from an area of high concentration to an area of low concentration. The movement of particles from an area of low concentration to an area of hight concentration, active process.

Question 5

Passive process

Answer 5

No energy is needed from the body.

Question 6

Osmosis

Answer 6

The movement of water molecules from an area of high concentration to an area of low concentration across a partially permeable membrane.

Question 7

Active process

Answer 7

Requires energy from the body.

Question 8

Dilute solution

Answer 8

More water molecules but less solute E.G. Salt, etc…

Question 9

Concentrated solution

Answer 9

Less water molecules but more solute E.G. Sugar, etc…

Question 10

Animal cell E.G. Skin cell, etc…

Answer 10

Dilute = lysis
Concentrated= Crenated

Question 11

Plant cell E.G.

Answer 11

Dilute= Turgid
Concentrated= Plasmolysed

Question 12

Flaccid

Answer 12

Soft

Question 13

Percentage change in mass

Answer 13

Final mass/Initial massx100

Question 14

Active transport

Answer 14

The process by which molecules move from an area of low concentration to an area of higher concentration.
Requires;
ATP energy and Carrier proteins in the cell membrane.

Question 15

Cell division

Answer 15

Humans are made up of aprox 60 billion cells.
All cells need to divide (Make more of themselves).
Why?
Replace damaged cells.
To allow us to grow.
Repair damaged tissues E.G. Muscle, etc…
To produce sex cells E.G. Sperm cells, etc…
All cells go through a ‘cycle’ before they divide. This is called the cell cycle.
There are three stages in the cell cycle.
Interphase-
This is the start of the cell cycle. In this stage the cell prepares itself to divide. The DNA is replicated (Doubled) and the organelles (Mitochondria and ribosomes) make copies of themselves. The cell grows in size.
Mitosis-
This is the second stage of the cell cycle. In this stage the chromosomes line up along the centre of the cell and get pulled to opposite ends. The nucleus divides.
Cytokinesis-
The cytoplasm and cell membrane divide. Two new identical cells are formed.

Question 16

Stem cells

Answer 16

Before a cell has differentiated, or specialised, it is called a stem cell.
A stem cell is a cell that has not yet become a specialised cell (Undifferentiated).
Features-
It can replicate many times.
It has the potential to become specialised E.G. Different types of cells, etc…
Two types of stem cells;
Embryonic stem cells can develop into almost every cell.
Adult stem cells found in adult tissues E.G. Bone marrow, etc…
These cells can only change into the same type of cell as the tissue they came from E.G. Liver stem cells, etc…

Question 17

Cell

Answer 17

The basic building blocks of life E.G. Muscle cell, etc…

Question 18

Tissue

Answer 18

Formed by lots of similar cells working together to perform the sam function E.G. Blood tissue, etc…

Question 19

Organ

Answer 19

Formed by lots of tissues working together E.G. Heart, etc…

Question 20

Organ system

Answer 20

Lots of organs working together in a system E.G. Circulatory system, etc…

Question 21

Organism

Answer 21

Is all of the body systems working together to form a living thing E.G. Human, etc…

Question 22

Food nutrients

Answer 22

Food nutrients are chemicals found in food.
Then main food nutrients are;
On our bio course-
Carbohydrates
Fats 

Proteins
Vitamins

Question 23

Carbohydrates

Answer 23

Give us energy.
There are 3 types of carbohydrates;
Sugar, starch and fibre. 
Starch and sugar give us energy.
Fibre prevents constipation.
Carbohydrates are made up of chains of simple sugars E.G. Glucose, etc...

Question 24

Protiens

Answer 24

Proteins are needed in the diet for;
Growth and repair of the body tissues.

Proteins are made up of long chains of amino acids.

Question 25

Lipids (Fats)-

Answer 25

Lipids are needed in the diet for; Energy and insulation (Keep us warm). Lipids are made up of one molecule of glycerol and three attached fatty acids.

Question 26

Enzymes

Answer 26

Enzymes are biological catalysts that speed up the rate of reaction in living things. Enzymes are specific. They can only catalyse (Break down) me substrate molecule. This is because they have a specific shape called the active site.

Question 27

Digestive enzymes

Answer 27

Carbohydrate enzymes break down carbohydrates into simple sugars. Protease enzymes break down proteins into amino acids. Lipase enzymes break down fats/lipids into fatty acids and glycerol. All of the digestive enzymes are made in the pancreas. The best/optimum temperature for enzymes is 37-40°C. This is when the rate of reaction will be the fastest. Above 40°C the enzymes active site starts to denature (Change shape).

Question 28

The circulatory system

Answer 28

It's made up of three parts. Blood, blood vessel (Tubes E.G. Arteries, veins and capillaries) and the heart. Blood travels all around our bodies in blood vessels (Blood tubes). There are 3 main types; Arteries, veins and capillaries. The heart pumps the blood all around the body.

Question 29

Arteries

Answer 29

Carry oxygenated blood (Usually) and under high pressure. | Narrow lumen and thick, muscular elastic walls.

Question 30

Veins

Answer 30

Carry deoxidised blood (Usually), under low pressure and veins have valves to prevent back flow of blood. Wide lumen , valves and thin wall.

Question 31

Capillaries

Answer 31

There are large number of tiny blood vessels called capillaries that link arteries and veins. They allow the exchange of substances E.G. O2, etc... One cell thick wall. The pulmonary artery is an artery that carries deoxygenated blood. The pulmonary vein is a vein that carries oxygenated blood.

Question 32

Double circulatory system

Answer 32

``` Mammals have a double circulatory system which means that; One circuit links the heart with the lungs and the other circuit links the heart with the rest of the body. L- left O- oxygenated R- right D- deoxygenated The blood goes to the right atrium from the vena cava down to the right ventricle out of the pulmonary vein up to the lungs back into the heart from the pulmonary vein down to the left atrium and left ventricle out of the aorta to the rest of he body. Aorta (To the entire body). Ven cava Right atrium Right ventricle Pulmonary artery (To the lungs). Pulmonary vein Left atrium Left ventricle Septum (Separates the two sides of the heart). ```

Question 33

Adaptations of the alveolus

Answer 33

You must mention structure and function in your answer. Structure- Alveoli have a very large surface area. Each alveolus is surrounded by a network of capillaries near the surface. The alveoli have thin moist walls. Function- This provides maximum diffusion of gases. To maintain a steep concentration gradient, this means a faster rate of diffusion. This provides a short (And quicker) diffusion pathway for gases.

Question 34

Plant transport tissues

Answer 34

Xylem tissue transports water and (dissolved) mineral ions from the roots to the stems and leaves. This movement is called transpiration. Phloem tissue transports dissolved food substance (Sugars E.G. Glucose) from leaves to the rest of the plant for immediate use or storage (Cell sap in vacuole). This movement is called transpiration. Both of these systems are rows of cells that make continuous tubes running the full length of the plant.

Question 35

Xylem

Answer 35

Dead tissue, no cytoplasm and hollow as well as thick walls made of lignin. Transports water and minerals from roots to the leaves.

Question 36

Phloem

Answer 36

Living tissue, tubes of elongated cells, made of companion cells as well as phloem sieve tubes and transports food. Transports food.

Question 37

Calculate the rate of movement of the air bubble (Transpiration)

Answer 37

SI units = cm/s Distance moved by the air bubble/time taken for the air bubble to move the distance

Question 38

Effect rate of transpiration

Answer 38

Light intensity, air movement, temperature and humidity.

Question 39

Communicable diseases

Answer 39

There are 2 main types of disease; Communicable diseases (Infectious diseases) are caused by pathogens. Pathogens are disease causing micro-organisms E.G. Some bacteria, etc... Communicable diseases can be passed on from one person to another E.G. Chicken pox, etc... Non-communicable diseases (non-infectious diseases) are not caused by pathogens. Non-communicable diseases can not be transferred from one person to another E.G. Most cancers, etc...

Question 40

Health

Answer 40

The state of physical and mental well-being.

Question 41

The human defence system

Answer 41

Protects the body against disease-causing micro-organisms E.G. Pathogens, etc... Human defence system General defence system The general defence system tries to stop pathogens from entering the bloodstream. It is made up of the body's natural barriers. They act against all pathogens. Barriers; Skin, platelets (Clot blood), Stomach acid (HCL), Hairs in nose, Cilia (In breathing track), etc... Specific defence system If the general defence system fails the body relies on the specific defence system. Made up of white blood cells (Found in the blood). White blood cells; Phagocytes- 'Engulf' pathogens Lymphocytes- produce antibodies which kill pathogens. Phagocytes are a type of white blood cell which engulf or ingest pathogens. Surround invader and digest it.

Question 42

White blood cells destroy pathogens

Answer 42

Phagocytes engulf pathogens. Lymphocytes produce antibodies which attach to the pathogens antigens and kill the pathogen. Some white blood cells produce antibodies.