Cell biology

• Recall and describe the function of a typical structure in a prokaryotic cell?

  Cell wall: Provides structural support and protection/strengthens the cell.

  cell membrane: controls movement into and out of the cell

  cytoplasm: where most chemical reactions occur

  bacterial DNA- (in a loop not enclosed in a nucleus) controls functions and synthesis protein

  plasmid DNA: rings of DNA used as vectors in genetic modification
• An example of a prokaryotic cell is a bacteria cell

  An example of a eukaryotic cell is a plant, animal, fungal cell
• three similarities between prokaryotes and eukaryotes?

  : both have a cell membrane, both have ribosomes, both have a cytoplasm, both have genetic material
• Give three differences between eukaryotic and prokaryotic cell?

  Prokaryotic cells genetic material is free in the cytoplasm

  Prokaryotic cells have plasmids

  Prokaryotic cells are smaller then eukaryotic
• Explain why mitochondria in cells are important?

  Cells require energy to function, mitochondria is the site of respiration , energy is released in respiration
• ribosomes synthesis protein so explain what this means?

  Synthesis means to produce, the proteins are made from anime acids so therefore riobsomes are the site of protein production
• What is the function o the nucleus?

  It contains the genetic material of the cell and controls the activities of the cell
• Name a cell that dosent have a nucleus?

  Sperm cell/ red blood cell / xylem cells / prokaryotic cell
• function of a sperm cells ? How is it adapted?

  Sperm cells transports male DNA by travelling towards and fertilising an egg for reproduction.

  -(Are streamlined)

  —Have 23 chromosomes in the nucleus. Has many mitochondria :to transfer energy to the tail ( the major site of respiration )

  -long tail : to propel the sperm to fertilise the egg

  -acromosome : contains enzymes to break through the eggs outer layer
• Function of a nerve cell, how is it adapted?

  Sends electrical impulses to the brain to the body

  -long axons: conduct electrical impulses in one direction, allows for rapid signalling

  -branched dendrites: to connect to other cells and form a network throughout the body

  -myelin sheath: insulates the electrical impulses

  -synapses: send neurotransmitter chemicals to another nerve cell or effector, gets released between a little gap between a nerve cell and another part of a nerve cell
• What does differentiation mean?

  how a cell changes over time to become specialised for a specific function
• Why do plant cell need to remain upright/ turgid with water ?

  to collect as much sunlight as possible for photosynthesis
• Plant cells have:

  cell wall- made of cellulose which strengths the cell

  vacuole- filled with cell sap with supports the plant

  chloroplasts- filled with chlorophyll, it’s used to absorb energy from sunlight to make glucose by photosynthesis
• plants are called producers since they can make their own food by photosynthesis