Topic 1

• name the two types of cells and give examples

  eukaryotes and prokaryotes

  eukaryotes- plant and animal cells

  prokaryotes- bacterial cells
• What a eukaryotic cell

  A type of cell which has their genetic material (DNA) is enclosed in their nucleus
• What's a prokaryotic celll


  A type of cell which has their genetic material (DNA) not enclosed in their nucleus but is a found in a single loop of DNA within the cytoplasm
• Name the sub cellular structures in an animal cell (5)

  nucleus, mitochondria, cytoplasm, cell membrane, ribosomes
• Name the sub cellular in plant cells (8)

  nucleus, mitochondria, cytoplasm, cell membrane, ribosomes, cell wall, chloroplasts and permeant vacuole
• Name the sub cellular structures in Bacteria (5)

  Cell membrane, cell wall, cytoplasm, plasmid (in some), circular strand of DNA
• What do bacteria's not have

  They have no internal membrane-bound structures so their DNA floats free in the cytoplasm and they have no nucleus, no mitochondria or chloroplast
• Nucleus (2)


  contains genetic material

  Controls the cells activities
• Cytoplasm (2)


  -A jellylike fluid inside the cell in which the organelles are found

  -where most chemical reactions take place
• cell membrane (1)


  - controls which substances can enter or leave the cell.
• Mitochondria


  -Where aerobic respiration takes place, provides energy
• aerobic respiration


  Respiration that requires oxygen
• ribosomes


  -site of protein synthesis
• Chloroplast *(2)


  -Site of photosynthesis;

  -contains chlorophyll which harvests light for photosynthesis
• permanet vacuole


  Filled with cell sap to help keep the cell turgid
• cell wall (2)


  -made from cellulose

  -provides strength to the cell
• the cell wall of bacteria is made up of

  peptidoglycan
• Some bacteria cells have (2)

  Plasmids (small loops of dna)

  and flagellum (thread-like structures that allows some bacteria cells to move around)
• Converting Units of Measurement

  U
• Sperm cells function


  -specialised to carry the males DNA to the egg cell for reproduction
• Sperm cells adaptations (4)


  -Long tail rotates which enables it to swim

  -Mid piece is full of mitochondria which releases energy for the tail

  -Acrosome stores digestive enzymes breaks down outer layer of egg cell so that the haploid nucleus can enter to fuse with the eggs nucleus

  -A large nucleus containing genetic information. 23 chromosomes haploid

  
• nerve cells function


  To carry electrical signals from one part of the body to another
• Nerve cells adaptations (3)

  -Has dendrites that carries electrical impulses over great distances

  -The branched structure provides a large surface area and forms a network with other neurones so that it can transfer electrical impulses.

  -Impulses travel along a central axon that is insulated by a fatty sheath that speeds up the rate of transfer of impulses.

  
• muscle function


  to contract quickly to move bones
• muscles adaptation (3)


  -special proteins (mysoin and actin) slipover each other, causing muscle to contract

  -lots of mitochondria to provide energy for contraction

  -can store glycogen used in respiration by mitochondria
• root hair function


  to take up water by osmosis and mineral ions by active transport from the soil
• Root hair cell adaptations (4)

  -large surface area increase rate of absorption of water

  -large permeant vacuole contains cell Sao which is more concentrated than soil water, maintaining a water potential gradient

  -mitochondria for energy needed in active transport

  -thinner walls. Water can move through easily due to shorter diffusion distance
• xylem cells function


  to transport water and mineral ions up the plant from the roots to the shoots
• Xylem cell adaptations (3)

  - Made up of dead cells.

  -No top and bottom walls between cells to form continuous hollow tubes through which water is drawn upwards towards the leaves by transpiration

  -chemical called lignin thickens the outer walls which strengthen the tubes which supports the plant
• phloem cell function


  to carry sugars and amino acids to all parts of the plants
• phloem cells adaptation (3)

  - made up of living cells which are supported by companion cells

  -cells are joined end to end and contain holes in the end cell walls (sieve plates) forming tubes which allows amino acids and sugars flow easily through by translocation

  - energy supplies by the mitochondria of the companion cells
• importance of cell division

  reproduction, growth, regeneration
• a specialised cell


  A cell adapted to carry out specific functions.
• examples of specialized cells

  Sperm cells, nerve cells, muscle cells, root hair cells, phloem and xylem cells
• (12) Microscope parts


  eyepiece, arm, nosepiece, body tube, objective lenses, stage clips, diaphragm, base, fine adjustment, coarse adjustment, stage, light source
• objective lens


  enlarges the image of the specimen
• Eyepiece lens


  the lens at the top that you look through
• name the two types of microscope

  -electron microscope

  -light (optical) microscope
• Which microscope achieves the highest magnification and greatest resolution?

  electron
• Resolution


  Ability of a microscope to distinguish two objects as separate