Cell Structure and Function

Golgi Apparatus Purpose and Process (4)

molecules in vesicles from the RER/SER travel to and fuse with the golgi apparatus. It then modifies and packages them into a new form (e.g. enzymes), which are then released as vesicles. Vesicles fuse with the cell membrane and are released to outside the cell.

Mitochondria Purpose (3)

produces atp, so that the cell can perform functions such as synthesising proteins and secreting proteins

RER purpose

contains ribosomes which are the location of translation in protein synthesis

Lysosomes Purpose

They contain enzymes for apoptosis, digesting pathogens, digesting old organelles

Prokaryotic vs Eukaryotic

similarities:

• cytoplasm

• cell membrane

• ribosomes

differences:

• eukaryotic: 80s prokaryotic: 70s ribosomes

• eukaryotic cells have membrane bound organelles, prokaryotic don’t

  • no nucleus, mitochondria, ER, has plasmids, nucleoids, slime capsule

• circular dna (nucleoid) vs nucleus

structure of golgi apparatus

stacks of cisternae, cis face receives proteins/lipids, trans face ships them out

structure of mitochondria

outer membrane, inner membrane (Cristae) which surrounds matrix, 70s ribosomes

process of gram + and gram -

1. crystal violet - both stain purple

2. add iodine (helps cv stick to cell wall)

3. add alcohol: lipids are easily dissolved by alcohol, so decolourised -. + stays purple since peptidoglycan is outer layer

4. add red safranin: + stays purple, - turns pink

Explain why gram positive bacteria and gram negative bacteria react differently to some antibiotics (3)

gram positive bacteria have a thick outer layer of peptidoglycan, so antibiotics which can't get through peptidoglycan layers will be more effective against gram negative. some antibiotics prevent enzymes from forming peptidoglycan, these are effective against gram positive bacteria

Compare and Contrast the Structure of the wall of gram + and gram - bacteria

(MUST 2 differences, 1 similarity)
peptidoglycan, lipopolysaccharide, periplasmic space

why is an electron microscope used over a light one? (2)

because it has a higher resolution, it is easier to distinguish the small distance between things, because the wavelength of electorns is shorter than in light

how to use a microscope? (5)

place x in solution, drop solution onto slide, stain, and use cover to cover it. Place under microscope and first using lowest power lens locate the x, then, focus on the x, before switching to high power lens (go from lowest mag to highest)

endotoxins are _____ found in ______ bacteria

1. lipopolysaccharides

2. gram neg

exotoxins are proteins produced by _____ bacteria

both gram + and gram -

Why are stains used? (2)

provides greater contrast, because the stain is taken up by specific parts of the cell

Process of protein synthesis to exocytosis (4)

- amino acids form peptide bonds in the ribosomes on the rER (translation)
- the enzyme is sent as a vesicle from rER to golgi apparatus
- at golgi apparatus it is modified, packaged, and secreted as a secretory vesicle
- travels from the golgi apparatus to the cell membrane where it binds with the membrane and is released

resolution vs magnification

resolution = ability to distinguish two structures, magnification = how zoomed in smth is

top of centrifugation is?

small molecules such as glucose, enzymes, amino acids, as they are less dense

heaviest to lightest organelles

nucleus, chloroplast, mitochondria, lysosomes, endoplasmic reticulum, ribosomes

Eukaryotic vs prokaryotic

80s AND 70s ribosomes in eukaryotic, only 70s in prokaryotic

No membrane bound organelle in prokaryotic