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Model of Cells - Basic Unit of Life - Coggle Diagram
Model of Cells - Basic Unit of Life
Cell theory
The cell is the basic unit of structure and organisation in all organisms
All cells come from pre-existing cells that have multiplied
All organisms are made up of one or more cells
Cell parts
Cell surface membrane/plasma membrane
Thin outer layer surrounds the cell
Partially permeable
A very thin layer of fats and proteins
Controls the movement of substances in and out of the cell
Cytoplasm
Contains largely water with different types of substances such as proteins, carbohydrates, fats and salts
Contains specialised structures called organelles with specific functions
Site where most cellular activities, occur, for example chemical reactions
Nucleus (plural: nuclei)
Contains chromatin. Chromatin coils to form rod-like structures called chromosomes.
In humans, each nucleus contains 46 chromosomes, arranged in 23 pairs. The chromosomes are made of a substance called deoxyribonucleic acid (DNA).
Each chromosome carries many genes. A gene is a section of a DNA that carries instructions for a specific characteristic. All the information on DNA determines how an organism will look like.
Controls all cellular activities. Cell will die if nucleus is removed.
Contains DNA, the hereditary or genetic material in living things passed down from parents to offspring.
Vacuole
A plant cell has a large central vacuole.
A fluid-filled space in a cell surrounded by a membrane.
An animal cell has numerous small vacuoles.
In plant cells, vacuoles store cell sap, containing liquid (water), nutrients (sugars, dissolved mineral salts etc.) and waste materials.
In animal cells, vacuoles store liquid, nutrients and waste materials.
Mitochondrion (plural: mitochondria)
A rod-shaped structure/organelle.
Energy released is used by cell for cellular activities, e.g. growth.
Cellular respiration occurs here. During cellular respiration, food substances are oxidised to release energy.
Chloroplast
Contains a green pigment called chlorophyll that absorbs light energy.
An oval-shaped structure/ organelle.
Allows photosynthesis to occur. During photosynthesis, light energy is absorbed and then used to convert carbon dioxide and water into sugars for the plant. Oxygen is produced in the process.
Cell wall
Fully permeable (i.e. allows all substances to move into and out of the cell).
Mainly made up of cellulose. Cellulose forms fibres which criss-cross over one another to form a very strong outer covering to the cell, surrounding the cell membrane.
Every plant cell has a cell wall.
Prevents the cell from bursting.
Provides rigidity and gives the cell a regular shape.
Protects and supports the cell.
Organisation of cells
Organelle
Cell
Tissues
Organs
Organ System
Organism
Unicellular
Eg. yeast, bacteria, amoebae
Made up of only 1 cell
Multicellular
Cells which are specialised in the same activity are organised together so they can work together
Made up of many cells
Different organs working together for a common purpose
Examples
Digestive
Enables physical and chemical breakdown of food to allow for absorption of nutrients
Skeletal
Allows movement, supports and protects many internal organs
Respiratory
Allows for gas exchange between the body's internal and external environment.
Circulatory
Circulates blood around the body to transport substances such as gases, nutrients and metabolic waste products
Different types of tissues that work together to perform a function
Simple tissues are made up of cells of the same kind.
Cells with similar structures grouped together to perform a shared function is called a tissue.
Complex tissues are made up of more than one type of cells
Division of labour
It is the breakdown of workload into smaller and more specific tasks for maximum efficiency
Different parts work together to ensure that the whole organism functions efficiently and effectively
Occurs at the cellular level, and in organisms