Biology unit 2
- Created by: rach555
- Created on: 19-05-18 15:51
View mindmap
- Unit 2
- Microscope
- Mag= Image / Actual
- Resolution- the power to distinguish two objects which are close in distance
- Magnification- how many times bigger the image is compared to the object
- Cell fractionation
- Cold- reduce enzyme activity
- Isotonic- prevent organelles bursting
- Buffered- so pH doesn't fluctuate
- 1.Homogenat-ion= homogeniser breaks up cells. Homogenate is filtered to remove debris
- Ultracentrifug-ation
- 1. Homogenate is spun at low speed so lightest organelles are put to bottom
- 2.Sediment removed and supernant is spun again
- 3. Supernant spun at higher speed until organelles sepe
- Eukaryotes
- Nucleus
- Mitochondria
- Double membrane, inner forms cristae
- Cristae provide large surface area
- Matrix contains proteins, lipids, ribosomes and DNA
- Site of aerobic respiration. Produce ATP
- Endoplasmic reticulum
- Rough- ribosomes on surface
- Large surface area for protein and glycoprotein synthesis
- Pathway for transport
- Smooth- no ribosomes
- Synthesise, store and transport lipids
- Synthesise, store and transport carbohydrates
- Rough- ribosomes on surface
- Golgi apparatus
- Made of stacks called cisternae
- Have small vesicles
- Function
- Add carbohydrate to proteins to make glycoproteins
- Produce secretory enzymes
- Secrete carbohydrates
- Transport, modify and store lipids
- Form lysosomes
- Lysosomes
- Hydrolyse material engested by phagocyte
- Digest worn out organelles
- Break down dead cells
- Ribosomes
- Site of protein synthesis
- 80S size
- Plants
- Chloroplasts
- Vacuoles
- Cell wall
- Prokaryotes
- Circular DNA- no nucleus
- Used for replication of cells
- Capsule
- Protects bacterium and sticks bacteria
- Cell-surface membrane
- Selectively permeable layer to control entry and exit of chemicals
- Cell wall- murein
- Physical barrier stopping certain substances
- Plasmid
- Possesses genes that aid survival
- Ribsomes
- 70S
- Site of protein synthesis
- May have flagella which help swimming
- Circular DNA- no nucleus
- Cell cycle
- Immune system
- Transport
- Diffusion
- Movement of molecules (small and non-polar)
- High to low concentration (down conc gradient)
- Osmosis
- Water moves from high to low water potential
- Down water potential gradient
- Through aqueous pores
- Pure water has potential of zero (high WP). Lower WP is more negative e.g.-30
- Animal cells
- High water outside so water enters
- Cell swells and bursts
- Low water outside so water leaves
- Cell shrinks
- High water outside so water enters
- Plant cells
- High water outside so water enters
- Cells swells and becomes turgid
- Cell doesn't burst due to cell wall strength
- Low water outside so water leaves
- Cell shrinks and becomes plasmolysed
- Cytoplasm membrane pulls away from cell wall
- High water outside so water enters
- Active transport
- Molecules and ions
- Uses ATP to change shape of carrier protein
- Uses carrier proteins
- Low to high concentration (against conc gradient)
- Used for co-transport
- Co-transport
- 1.Sodium ions actively transported out of epithelial cells into blood
- 2.High conc of sodium ions in lumen. Low in the E cells
- 3.Sodium ions diffuse into E cells from lumen
- 4.Glucose moves with it by facilitated diffusion
- Facilitated diffusion
- Charged ions and polar molecules
- Protein channels and carrier proteins
- Down concentration gradient
- Diffusion
- Cell division
- Mitosis
- 1.Prophase- chromosomes become visible. Centrioles go to opposite poles and develop spindle fibres. Nuclear envelope disappears
- 2.Metaphase- spindle fibres attach to centromere and chromosomes are lined up along equator
- 3.Anaphase- Centromeres divide and spindle fibres pull chromatids apart
- 4.Telophase- nuclear envelope reforms and spindle disappears
- 5.Cytokinesis- cytoplasm divides
- Importance
- Growth
- Repair
- Reproduction
- Prokaryotic cells- binary fission
- 1. Circular DNA replicates and attaches to different ends of cell membrane
- 2. Plasmids replicate
- 3. Cell membrane grows between DNA and divides cytoplasm
- 4. New cell wall forma and divides cell
- Viruses
- 1.Attach to host cell by attachment proteins
- 2.Inject nucleic acid into host cell
- 3.Nucleic acid has genetic info that provides instructions
- 4.Instrucftions for producing viral components, nucleic acid, enzymes and structural proteins
- Mitosis
- Viruses
- Acellular and non-living
- Capsid
- Contain nucleic acids
- Lipid ennvelope
- Attachment proteins
- Microscope
Comments
No comments have yet been made