cells

• cell membrane is made up of lipids (proteins) and is a partially permeable membrane, which only allows small and soluble substances to pass through.
• cell wall surround the cell membrane and is made of cellulose. It is fully permeable and protects the cell from injury and gives it a fixed shape.
• cytoplasm is the site of cellular activities and contains organelles
• nucleus controls cell activities and contains hereditary information (chromosomes, DNA, chromatin thread) essential for cell division.
• chloroplast contains chlorophyll which is required for photosynthesis.
• vacuole is a fluid-filled space enclosed by a partially permeable membrane. it stores substances within the cell.
• plant cells have one large (central) vacuole consisting of sugars, mineral salts and amino acids.
• animal cells have numerous small vacuoles that store water and food substances. it only exist temporarily.
• Rough endoplasmic reticulum (RER) appears rough because of ribosomes attached and transports proteins made by ribosomes to the golgi apparatus.
• ribosomes synthesizes proteins and can be attached to RER or lying freely in cytoplasm.
• smooth endoplasmic reticulum (SER) synthesizes substances (fats, steroids) and is involved in detoxification.
• golgi body is flattened spaces that chemically modifies substances by ER then stores and packages the substances in vesicles to be secreted out of the cell.
• function of golgi body

  
• mitochondria is the site of aerobic respiration and oxidize food to release energy for cellular activities.
• plant cells have cell wall, a large central vacuole and chloroplast while animal cells doesn't.
• differentiation is the process which a cell becomes specialized for a specific function.
• red blood cells contain haemoglobin which binds oxygen and transports it around the body.
• red blood cells have a biconcave shape which increases surface area-to-volume ratio for increased rate of oxygen uptake.
• red blood cells do not have nucleus to allow packing of more haemoglobin for transport of oxygen.
• red blood cells are flexible so that it can squeeze through capillaries.
• muscle cells contain many nuclei for cell division
• muscle cells have many mitochondria to provide energy for contraction of muscle cell.
• root hair cell is long and narrow to increase surface are-to-volume ratio for increased rate of absorption of water and mineral salts.
• root hair cells maintain lower water potential in vacuole to allow water to enter the cell via osmosis.