cells

• what is a cell

  A cell is a basic unit of life
• what can only be found in the plant cell

  chloroplast, large central vacoule and cell wall
• function of cell surface membrane

  It controls substances entering and leaving the cell
• function of cytoplasm

  it is the site of many chemical reaction
• fucntion of functionvacuole

  contains air, food or liquid particles
• function of nucleus

  contains genetic materials (DNA) in chromosomes, controls all cell activities such as cell reproduction, growth of cell, repair of worn-out parts
• function of cell wall

  supports the cell and gives it a regular shape and protects the cell from injuries or prevent the cell lysis
• cell wall

  made up of cellulose, fully permeable
• function of large central vacuole

  contains cell sap, which contains water , sugar, and salt( dissolve substances) and also keep cell firm or turgid by in water
• what structure can be seen only under the electron microscope

  nucleus, mitochondrion, rough endoplasmic reticulum, smooth endoplasmic reticulum, ribosomes and golgi body
• function of mitochondrion

  aerobic respiration occurs in mitochondrion. Food is oxidised in aerobic respiration to release energy for cell activities
• function of rough endoplasmic reticulum

  It transports proteins from the ribosomes to the golgi apparatus for the secretion out of the cell
• why is the rough endoplasmic reticulum rough?

  due to the presence of ribosomes attached to its outer surface
• function of smooth endoplasmic reticulum

  It synthesis fats and steroids, and converts harmful substances into harmless materials. (detoxification)
• function of ribosomes

  They are needed to synthesise proteins in the cell
• functions of ribosomes that are attached to the membrane

  they make proteins that are usually transports out of the cell
• where can you find ribosomes 


  They lie freely in the cytoplasm, make proteins that are used in the cell
• golgi body/ golgi apparatus 


  chemically modify substances made by the ER, stores and packages these substances in the vesicles for secretion out of the cell
• function of muscle cell

  They contract to support movement I animales
• adaptation of muscle cell

  Elongated and cylindrical shape and contains many mitochondria
• why does the muscle cell requires mitochondria

  higher rate of aerobic respiration, release more energy for contraction of muscle cell and bring out movement
• function of root hair cell and where are they found

  found in the root of the plant for the absorption of water and mineral salts from the surrounding soil into the plant
• adaptation of root hair cells 


  Root hair cells has a long and narrow extension
• why does the root hair cell has a long and narrow extension

  to increase the surface area to volume ratio which increases the rate of absorption of water and mineral salts
• function of red blood cell

  they are used for the transportation of oxygen from the lungs to the rest of the body
• adaptation of red blood cell

  contains haemoglobin, does not contain a nucleus, biconcave in shape and flexible
• why do red blood cells contain haemoglobin

  to bind with oxygen to transport it from the lungs to all body cells
• why does red blood cell not contain a nucleus

  to contain ore haemoglobin for the transportation of more oxygen
• why does is the red blood cell biconcave in shape

  to increase surface area to volume ratio to increase the rate of diffusion of oxygen into and out of the cell
• why are red blood cells flexible

  to change shape and allow blood capillaries to squeeze through easily
• adaptations of epithelial cells

  contains microvilli and mitochondria
• what is the function of the microvilli

  it is to increase surface area to volume ratio for higher rate of absorption of digested materials
• what is the function of mitochondria in epithermal cell in small intestine

  it has a large number of mitochondria to release more energy for absorption of digested nutrients (by active transport)
• why do red blood cells contain hemoglobin

  to bind with oxygen to transport it from the lungs to all body cells
• function of chloroplast

  contains chlorophyll which absorbs light energy from the sun and convert it to chemical energy to make food during photosynthesis
• what is the process of secretion of substances in the cell

  Ribosomes read the information and synthesise the proteins accordingly.
• what is the process of secretion of substances in the cell

  Nucleus sends information for the making of proteins to ribosomes.

  Ribosomes read the information and synthesis proteins accordingly.

  Vesicles transport substance within the cell. Small vesicles containing substances made by the ER are pinched off from the ER.

  These vesicles then fuse with the golgi apparatus and release their contents into the golgi apprartus. The substances made by the ER may be modified inside the golgi apparatus.