igcse biology

Nutrition

Provide living organisms with energy and raw material for growth and repair.

Respire

Living organisms release energy from their food.

Excretion

The removal of waste products such as carbon dioxide and urine carried out by the skin, the lungs and the kidneys.

Response

Nerve coordination and reaction to stimuli.

Reproduction

To produce offsprings for their species to survive.

Cells

Tiny building blocks of living organisms.

Multicellular

Organisms that contain a lot of cells and therefore need organisation.

Organelles

Tiny structures within cells.

Nucleus

Contains genetic materials that control the cell's activities.

Cell membrane

Outer surface of the cell and control movement of substances in and out.

Cytoplasm

Place of most chemical reactions and contain enzymes.

Chloroplasts

Contain chlorophyll and carry out photosynthesis.

Cell wall

Rigid structure made of cellulose that supports and strengthens cells.

Vacuole

Large organelle that contains cell sap.

Cell sap

A weak solution of sugars and salts.

Tissue

A group of similar cells that work together to carry out particular function.

Xylem tissue

For transporting water and mineral salts in plants.

Phloem tissue

For transporting sucrose and amino acids in plants.

Organ

A group of different tissues that work together to perform a function.

Organ system

A group of organs that does a particular job.

Cereals

Example: maize

Herbaceous legumes

Example: beans and peas

Mycelium

A structure of fungi.

Hyphae

Thread like structure that make up mycelium.

Saprotrophic nutrition

Fungi that secret extracellular enzymes into the area outside their body to dissolve their food, so they can then absorb the nutrients.

Yeast

A single-celled fungus.

Mucor

Multicellular fungus and has a mycelium and hyphae.

Chlorella

Protoctists, plant-cell-like

Amoeba

Protoctists, animal-cell-like

Lactobacillus bulgaricus

Bacteria, can be used to make milk go sour and turn into yoghurt.

Pneumococcus

Bacteria, spherical in shape, causes pneumonia.

Viruses

Particles and smaller than bacteria

Parasites

Organisms that depend on other organisms to live.

Tobacco mosaic virus

Makes the leaves of tobacco plants discoloured by stopping them from producing chloroplasts.

Pathogens

Organisms that cause disease. (include fungi, protoctists, bacteria and viruses)

Plasmodium

Protoctists, causes malaria

Influenza virus

Viruses, causes flu and HIV which causes AIDS.

Enzymes

A substance that speeds up the speed of a reaction without being changed or used up in the reaction. Made up of chains of amino acids.

Metabolic reactions

Useful chemical reactions inside the body.

Substrate

A molecules that is changed in the reaction.

Active site

The part where a substrate joins on to the enzyme.

Optimum temperature

When reaction goes fastest.

Iodine solution

A solution where iodine is dissolved in potassium iodide to test the presence of starch. If starch is present, then the solution will turn fro orange-brown to blue-black.

Diffusion

The net movement of particles from an area of higher concentration to an area of lower concentration.

Osmosis

The net movement of water molecules across a partially permeable membrane from a region of higher water potential to a region of lower water potential.

Turgid cells

When cells have drawn in water by osmosis and become plump and swollen.

Turgor pressure

When the contents of the cell push against the cell wall, and helps support the plant tissues.

Flaccid cells

When cells lose water and their turgor pressure and starts to wilt.

Active transport

The net movement of particles against a concentration gradient (ie. from an area of lower concentration to an area of higher concentration) using energy released during respiration.

Carbohydrates

Starch and glycogen are large, complex carbohydrates, which are made up of smaller units (glucose and maltose) joined together in a long chain.

Proteins

Long chains of amino acids.

Lipids

Fats and oils that are built from fatty acids and glycerol.

Benedict's reagent

A blue solution to test the presence of glucose.

Function of carbohydrates

To provide energy.

Function of lipids

To provide energy, act as an energy store and provide insulation.

Function of proteins

Growth and repair of tissues, emergency source of energy.

Function of vitamin A

To improve vision and keeping skin & healthy.

Function of vitamin C

To prevent scurvy.

Function of vitamin D

For calcium absorption.

Function of calcium

To make bones and teeth.

Function of iron

To make haemoglobin for healthy blood.

Function of water

As a constant supply to replace water lost through urinating, breathing and sweating.

Function of dietary fibre

To aid the movement of food through the gut.

Calorimetry

Food can be burnt to measure how much energy it contains.

Function of bile

Neutralises hydrochloric acid from the stomach and emulsifies fats.

Alimentary canal

Gut.

Function of mouth (I)

Salivary glands in the mouth produce amylase enzyme in the saliva.

Function of mouth (II)

Teeth break down food mechanically.

Function of oesophagus

The muscular tube that connects the mouth and stomach.

Function of liver

Produce bile.

Function of gall bladder

Store bile.

Function of stomach (I)

Pummels the food through its muscular walls. tr

Function of stomach (II)

Produce protease enzyme, pepsin.

Function of stomach (III)

Produce hydrochloric acid to kill bacteria & give the right pH for protease enzyme to work (pH2)

Function of pancreas

Produce lipase, protease and amylase and release them into the small intestine.

Function of small intestine (I)

Produce lipase, protease and amylase again to complete digestion.

Function of small intestine (II)

Absorption of nutrients.

Function of large intestine

To absorb excess water.

Function of anus

To excrete faeces.

Persistalsis

Waves of circular muscle contractions to squeeze and push boluses along the gut.

Bolus

Balls of food.

Ingestion

Physical action of eating food.

Digestion

The break down of large, insoluble molecules into small, soluble molecules. Mechanical is through teeth and stomach muscles, whereas chemical is through enzymes and bile.

Absorption

The process of moving molecules through the walls of the intestine into the blood.

Assimilation

When the digested food molecules have been digested, they are being moved into body cells and become parts of them.

Egestion

The process of getting rid of undigested, waste materials.

Photosynthesis

The process in plants where carbon dioxide and water are being converted into glucose and oxygen in the presence of sunlight and chlorophyll.

Vascular bundles

The transport vessels xylem and phloem in the mesophyll.

Translocation

The movement of food substances around the plant.

Transpiration

Loss of water from the plant through evaporation and diffusion.

Potometer

A piece of apparatus used to estimate the transpiration rate.

Respiration

The process of releasing energy from glucose in the mitochondria of a cell.

Thorax

The top part of the body.

Diaphragm

Separating the upper and lower part of the body.

Ribcage

To protect the lungs.

Pleural membranes

Material that surrounds the lungs.

Trachea

The windpipe where air goes into the lungs.

Bronchus

One of the 2 branches of trachea that lead to each lung.

Bronchioles

Smaller tubes split from a bronchus.

Alveoli

Site of gas exchange at the end of bronchioles.