Structure and function of living organisms 1

What are the levels of organisation?

• Organelle: Part of a cell with a specific function

• Cell: The basic structural unit of all living organisms

• Tissue: A group of cells that work together to perform a specific function

• Organ: A group of tissues that work together to perform a specific function

• Organ System: A group of organs that work together to perform a specific function

What structures only belong to a plant cell and what are their functions.

• Cell Wall: It is made up of a complex carbohydrate, cellulose, which is rigid to keep the shape of the cell and strengthens and supports the cell

• Chloroplasts: Contain chlorophyll, which traps energy from sunlight to be used for photosynthesis

• Vacuole: Contains the cell sap

What are come specialisation cells?

Nerve cell:- Have an elongated axon to carry nerve impulses.

Leaf palisade cell:- Have a lot of chloroplasts and large surface area for photosynthesis.

Sperm cell:- Has a tail for swimming and contains the father’s genes, found in the male testis.

Root hair cell:- Has a large surface area to absorb loads of water and thin cell wall to absorb water easily with a large vacuole to store the water. They absorb minerals and water from the soil.

What are carbohydrates?

• They are made up of Carbon, Hydrogen and Oxygen

• Most of the carbon dioxide on our body comes form starch.

  • a large insoluble molecule

  • a polymer of glucose

  • include foods like bread and pasta.

What are proteins?

• They are made up of carbon, hydrogen, oxygen and nitrogen.

• Needed for growth and repair of tissues.

• Building blocks for proteins are amino acids.

Where are lipids found?

Found in oils and fats.

What are enzymes?

• Enzymes are special proteins

• Biological catalysts that speed up the rate of reaction without being used up.

How does an enzyme break down carbohydrates?

• Starch is a polymer of glucose so it is broken down with the enzyme AMYLASE to form maltose which is basically 2 glucose molecules joined together.

• Maltose id further broken down with the enzyme MALTASE to form single glucose molecules small enough for us to absorb.

How do enzymes break down proteins?

• They use the enzyme PROTEASE to break proteins down into amino acids.

  • Protease is a group of enzymes with specific enzymes like PEPTIDE and TRYPSIN

How do enzymes break down lipids?

• they are broken down with the enzyme lipase which break them down into smaller molecules like glycerol and fatty acids.

What is bile?

• Bile is a green fluid made in the liver and stored in the gallbladder.

• It emulsifies lipids

• It neutralises stomach acid.

• It has a large surface area and aids enzyme action.