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Flashcards in Key Terms Deck (42):


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



It's the ability to distinguish between 2 points.


General formula for standard index form




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.


Passive process

No energy is needed from the body.



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


Active process

Requires energy from the body.


Dilute solution

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


Concentrated solution

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


Animal cell E.G. Skin cell, etc...

Dilute = lysis
Concentrated= Crenated


Plant cell E.G.

Dilute= Turgid
Concentrated= Plasmolysed





Percentage change in mass

Final mass/Initial massx100


Active transport

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


Cell division

Humans are made up of aprox 60 billion cells.
All cells need to divide (Make more of themselves).
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.
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.
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.
The cytoplasm and cell membrane divide. Two new identical cells are formed.


Stem cells

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).
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...



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



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



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


Organ system

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



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


Food nutrients

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




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...



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

Proteins are made up of long chains of amino acids.


Lipids (Fats)-

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.



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.


Digestive enzymes

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).


The circulatory system

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.



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



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



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.


Double circulatory system

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).


Adaptations of the alveolus

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.


Plant transport tissues

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.



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



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


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

SI units = cm/s

Distance moved by the air bubble/time taken for the air bubble to move the distance


Effect rate of transpiration

Light intensity, air movement, temperature and humidity.


Communicable diseases

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...



The state of physical and mental well-being.


The human defence system

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.
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.


White blood cells destroy pathogens

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