A2.2 Cell Structure

list and outline 8 processes that all living organisms exhibit

1. metabolism- cellular chemical reactions that syntehsise macromolecules

2. response to stimula - reacting to changes in an env

3. homeostasis - maintainace of internal conditions

4. movement - controlling place and position

5. growth - cell grow in size and or # (in a multicellular organism)

6. reproduction - production of an offspring sexualy or asexually

7. excretion - removal of metabolic waste products

8. nutrition - intake or production of nutrients

Cell Theory

1. all living things are made up of individual units of cells

2. cells are the basic unit of life

3. all cells arise from pre-existing cells

Order from largest to smallest and which can be seen with a light microscope

• molecule

• viruses

• prokaryote

• eukaryote

• organelles

• membrane width

1. eukaryote

2. organelle

3. prokaryote

4. viruses

5. membrane width

6. molecule

What are the resolutions of the light microscope and electron microscope?

LM: 200 nm

EM: 0.1 nm

What is the magnification and function/ purpose of the EM?

<10 million X

show ultrastructure of dead/ preserved cells

Outline the 2 developments in electron microscopy

1. free fracture electron microscopy

• freeze tissue, and break it with a special tool “moleular hammer”

• observe fragments using an EM to see the internal structure

• e.g. discovery of phospholipid bilyer with embedded proteins

2. cryogenic electron microscopy

• freeze tissue to cryogenic temepratures

• stop molecular vibrations, become more stable

• has a better resolution, thus reduce damage from the electron beam

• e.g. imaging of a protein

Outline 1 development in microscopy

1. fluorescent stains

• add dyes to specific cell structures, so when light is radaited on the specimen, the labelled area appears bright

• e.g. show small molecules suhc as proteins

• immunofluorescence

  • create antibodies designed to attach to specific things (e.g. protein)

  • stain these antibodies, and track movement of it with the same method

Outline 3 structures comon to cells

1. DNA

• genetic material; stores and transfers information

• codes for diversity of proteins

• heridetery to offspring

2. cytoplasm

• composed of cytosol

• aqueous solution that contains organic compouds, ions, inorganic compounds

• site of most metablic reactions occurring

3. Plasma membrane

• composed of lipids that compartmentalise the cytoplasm and protects contents

• selective permeabiity

• contains proteins for cell-cell communication, trasnport, cella dhesion, cell identity

9 structures in a prokaryotic cell

1. 70S ribosomes

2. Cell wall composed of peptidoglycan

3. Cytoplasm

4. Naked DNA in the nucleoid region

5. Cell membrane for compartmentalisation

6. Flagella for locomotion

7. Plasmid for horizontal gene transfer

8. Slime Capsule (sometimes) that aids attachment

9. Pili that aids attachment or transfer of DNA

15 structures in an animal cell

1. nucleus holds DNA and produced ribosomes

2. cytoplasm

3. cytoskeleton

4. plasma membrane for compartmentalisation

5. 80S ribosomes

6. golgi apparatus for processing polypeptides

7. mitchondria that carries out cellular respiration

8. RER for protei synthesis

9. SER for lipid synthesis

10. vacuole for storage, relatively small

11. centrioles for mitosis

12. vesicles for transport or storage

13. lysosome for digesting foreign bodies

14. cilia (sometimes)

15. flagella (sometimes)

13 structures in a plant cell

1. nucleus holds DNA and produced ribosomes

2. cytoplasm

3. cytoskeleton

4. cell wall composed of cellulose

5. plasma membrane for compartmentalisation

6. 80S ribosomes

7. golgi apparatus for processing polypeptides

8. mitchondria that carries out cellular respiration

9. RER for protei synthesis

10. SER for lipid synthesis

11. Sap vacuole for osmotic pressure, relatively large

12. vesicles for transport or storage

13. plastids/ chloroplast for photosynthesis

structures in a fungal cell

1. cell wall composed of chitin (polysaccharide)

2. vacuoles to break down unwanted molecules and stores ions and molecules (relatively large)

3. centrioles

4. bud for asexual reproduction

5. cytoskeleton for structural support

unicellular of multicellular?

1. bacteria

2. animal

3. plant

4. fungal

bacteria: unicellular

animal: unicellular (paramecium) or multicellular (human)

plant: multicellular

fungal: unicellular (yeast) or multicellular (mushroom)

2 examples of each multinucleated or anucleated

multinucleated: skeletal muscle, aseptate fungal hyphae

anucleated: RBC, phloem sieve tube

What are kingdoms of life?

classifications of livign organisms

e.g. animal, plant, fungi

magnification powers

low: 40X

medium: 100X

high: 400X

eyepiece graticule major division lengths

40X low power: 250um = 0.25mm

100X medium power: 100um = 0.1mm

400X high power: 25um = 0.025 mm