biology cell structure

• cell membranes are made out of lipids and proteins
• cell membrane contains partially permeable membrane that allows small and soluble substances to pass through
• the cell wall is made up of cellulose
• The cell wall is fully permeable
• The cell wall protects cell from injury and gives cell a fixed shape.
• the cytoplasm is the site of cellular activities
• the cytoplasm contains specialised structures called organelles
• The nucleus is surrounded by a nuclear membrane
• The nucleus controls cells activities such as growth and repair
• The nucleus is essential for cell activities
• The nucleus contains DNA
• The cell vacuoles is a fluid-filled space enclosed by a partially permeable membrane.
• In animal cells, there are numerous small vacuoles that store food and water substances
• In plant cells, there is usually one large central vacuole that stores sugar, mineral salts and amino acids
• The mitochondria is a sausage shaped/oval/rod-like organelle
• aerobic respiration occurs in the mitochondria to release energy for cell activities such as growth and reproduction
• Ribosomes are small and round structures
• Ribosome synthesises protein.
• The ribosomes can be find on organelles within the cell lying freely in the cytoplasm
• there are 3 types of specialised cells which are red blood cells, muscle cells and root hair cells
• red blood cells contain haemoglobin
• Red blood cells have a circular biconcave
• red blood cells do not have a nucleus
• red blood cells are flexible
• red blood cells transport oxygen around the body
• Red blood cells increases surface area-to-volume ratio for increased oxygen uptake
• red blood cells allow packing of more haemoglobin for transport of oxygen
• red blood cells easily squeezed through the capillaries
• The muscle cells contain many mitochondria
• the muscle cells have contractile protein fibres
• the muscle cell provide energy for contraction
• root hair cells have a narrow and long protrusion
• root hair cell maintains a lower water potential in vacuole
• root hair cells increase surface area-to-volume ratio for increased absorption of water and mineral salt
• root hair cells allow water to enter root hair cell via osmosis