Level of organisation/cell structure Flashcards
What are the different levels of organisation and their order?
(In order of size from smallest to largest)
Organelle Cells Tissues Organs Organ system
What are organelles?
Tiny structures within cells
What are the typical organelles found in plant cells?
Nucleus
Cell membrane
Cytoplasm
What is the role of the nucleus?
Contains genetic material that controls the cell activities. Its surrounded by its own membrane.
What is the role of the cell membrane?
Forms the outer shell of the cell and controls the substances that go in and out of the cell.
What is the role of the cytoplasm?
A gel like substance where most of the cells chemical reactions take place. It contains enzymes which control these reactions.
What extra organelles do plant cells have (still contain all animal organelles) ?
Chloroplasts
Cell wall
Vacuole
What is the role of the chloroplasts?
Photosynthesis which makes food for the plant and contains a green substance called chlorophyll.
What is the role of the cell walls?
A rigid structure made of cellulose which surrounds cell membrane. It supports and strengthens the cell.
What is the role of the vacuole?
Contains cell sap (a weak solution of sugars and salts). It helps support the cell.
What are specialised cells?
Specialised so that they carry out a particular function (structures are varied)
Give two examples of specialised cells
Red blood cells - specialised for carrying oxygen
White blood cells - specialised for defending out body against disease
What are tissues?
A group of similar cells working together to carry out a particular function
Give examples of a tissue
Xylem and phloem tissue in plants
What can a tissue contain more than one of?
A cell type
