Topic 4 - Cell Structure

Question 1

types of coccus

Answer 1

strepto - divide along same plane, diplo - make pairs of 2 cocci after division, tetrad - divide along 2 planes, sarcinae - divide along 3 planes, cluster divide along any plane irregularly

Question 2

features of a prokaryotic cell

Answer 2

chromosome free in cytoplasm, plasma membrane, no membrane enclosed organelles

Question 3

the bacterial nucleoid

Answer 3

single free chromosome in the cytoplasm, no surrounding membrane, supercoiling to help fit in the cell

Question 4

the bacterial cell envelope

Answer 4

the inner plasma membrane (cytoplasmic), the cell wall (peptidoglycan), exterior layers including capsule, polysaccharide matrix or slime (glycocalyx)

Question 5

cytoplasmic membrane

Answer 5

semi-porous barrier, permeable to specific molecules, glycoproteins help transport, hydrophilic outside, hydrophobic inside

Question 6

types of transport across membrane

Answer 6

simple diffusion, facilitated diffusion (with concentration gradient no energy used), active transport (against concentration gradient, energy used)

Question 7

peptidoglycan sacculus

Answer 7

is a polymer of glycans cross linked by peptides typically 4 amino acids long

Question 8

gram positive peptidoglycan

Answer 8

tight and regular bonding

Question 9

gram negative peptidoglycan

Answer 9

open and fewer bonds

Question 10

Mycoplasmas

Answer 10

have no cell wall, respiratory pathogen causes walking pneumonia, pleomorphic, requires a host to survive

Question 11

Cell walls can be broken down by what

Answer 11

lysozyme hydrolyses peptidoglycan

Question 12

3 possible outcomes for a punctured cell wall

Answer 12

shrink if external solute concentration is greater, stay the stay, or swell and burst if internal has a greater concentration than outside