LECTURE 6

Question 1

Peptidoglycan

Answer 1

A thin sheet composed of

1) chains of repeating disaccharide unit composed of two monosaccharides
2) small peptides

Question 2

What are the two monosaccharides that compose the repeating chain of disaccharides in peptidoglycan

Answer 2

1) N-acetylglucosmine (NAG)

2) N-acetylmuramic acid (NAM)

Question 3

Small peptides that make up peptidoglycan

Answer 3

• attaches to NAM peptides in adjacent chains, cross-linking the chain, making them stronger

Question 4

Where does the short peptide get added to?

Answer 4

Gets added to the NAM

Question 5

How do tw peptide side chains attach to each other

Answer 5

Via covalent bonds

Question 6

Transpeptidation

Answer 6

The cross linking reaction of two peptide chains, this adds strength

Question 7

Is peptidoglycan a barrier to solutes, why or why not?

Answer 7

No, because the opening are to large.

Question 8

As. A bacteria grows, peptidoglycan

Answer 8

Is produced more.

Question 9

Some antibiotics are specific to certain bacteria, what is this based on.

Answer 9

Based on their ability to target prokaryotic-specie structures.

Question 10

Two common targets for antibiotics are

Answer 10

1) Prokaryotic ribosomes

2) Prokaryotic cell walls

Question 11

What does it mean for a cell to lyse ?

Answer 11

For it to burst

Question 12

Lysozyme

Answer 12

An enzyme that catalysts hydrolysis of B 1-4 linkages between NAG and NAM

Peptidoglycan falls apart, causing the cell to lyse.

Question 13

Staphylococcus

Answer 13

Gram positive bacterium

Question 14

As bacterial cells grow, it synthesizes more

Answer 14

Peptidoglycan

Question 15

How does penicillin work?

Answer 15

1) transpeptidation is catalyze by a specific enzyme
2) penicillin inhibits this enzyme
3) peptidoglycan weakens
4) eventually the cells bursts (lysis)

Question 16

What does penicillin work best on ?

Answer 16

Gram positive cells

Question 17

Many bacteria besides having a cell wall also have a

Answer 17

Capsule

Question 18

What is a capsule made of

Answer 18

Mostly polysaccharides

Question 19

Capsules functions

Answer 19

1) protects from environment

2) stick bacteria to surface

Question 20

What i sa capsule rare is

Answer 20

Archaea

Question 21

Two types of pili

Answer 21

1) Fimbriae

2) sex pilus

Question 22

Fibriae

Answer 22

Attaches to surface of host cells

Gonorrhoea uses fumbriae to attached itself to mucus membranes

Question 23

Sex pilus

Answer 23

Transfers DNA or plasmid between bacteria cells

Question 24

Bacterial conjugation

Answer 24

DNA is transfers to another bacteria

Question 25

Plasmid

Answer 25

A small circular DNA distinct form the chromosome

Question 26

In a heterogenous environment, many bacteria exhibit

Answer 26

Taxis

Question 27

Taxis

Answer 27

The ability to move towards or away from a stimulus

Question 28

Chemotaxis

Answer 28

Movement towards or away from a chemical stimulus

Question 29

How do motile bacteria move

Answer 29

In a series of runs and tumbles

Question 30

What happenes if the concentration of the attractant increases during the run

Answer 30

The duration of the run is longer.

Question 31

Who has flagella

Answer 31

Bacteria, archaea, and eukaryotes

Question 32

What is the flagella composed of ?

Answer 32

Different proteins that evolved independently

Question 33

What is the flagella used for ?

Answer 33

Movement. ``` CCW = run CW = tumble ```

Question 34

What does E.coli use to power its motor

Answer 34

A proton-based (H+) electrochemical gradient

Question 35

Archaea cell walls

Answer 35

- no outer membrane - coverings surrounding plasma membrane, produces a stronger membrane - no peptidoglycan

Question 36

What are some archaea covered in ?

Answer 36

Archaea specific lipopolysacchrides

Question 37

Eukaryotic cell walls

Answer 37

- provides shape and protection | - cellulose chains embedded in a matrix of other polysaccharides and proteins

Question 38

Do animal cells have cell walls

Answer 38

NO

Question 39

Ho has cells walls

Answer 39

Plants and fungi

Question 40

Plant cell walls

Answer 40

- young plant cells secrete a thin cell wall outside the plasma membrane - primary cell wall - secondary cell wall

Question 41

Primary cell wall

Answer 41

- able to expand as the cell grows - older the cell, stronger the membrane - secrete hardening substances into primary

Question 42

Secondary cells wall

Answer 42

- may have many layers | - made of matrix of strong materials

Question 43

Cells in wood have many layers of

Answer 43

Cellulose, lignin, proteins

Question 44

Between primary cell walls of adjacent plant cells is the

Answer 44

Middle lamella

Question 45

The middle lamella is composed of

Answer 45

Sticky polysaccharides called pectins

Question 46

Pectin

Answer 46

Glues the adjacent cells together

Question 47

How are pectin and amylopectin different

Answer 47

Pectin is referring to a mixture of polysaccharides, more complex structure.

Question 48

Ripening first gets soft in part due to the real down of

Answer 48

Pectin

Question 49

Because of the thick cell wall and middle lamella, plant cells are

Answer 49

Isolated form each other

Question 50

What enables plant cells to communicate with the thick cell wall and middle lamella ?

Answer 50

Plasmodesmata

Question 51

Plasmodesmata

Answer 51

Pores that allows H2O and small solutes to pass.

Question 52

The pores of plasmodesmata can open and close depending on

Answer 52

environmental conditions or age of plant

Question 53

What is the order or membranes in a plant cell from outermost to inner most

Answer 53

Plasma membrane Secondary cell wall Primary cell wall Middle lamella

Question 54

Animal cella

Answer 54

- no cell wall, but secrete proteins and polysaccharides = extra cellular matrix (ECM)

Question 55

How do cells attach to the ECM

Answer 55

Using additional specialized proteins

Question 56

What are the specialized protein see to attach to ECM?

Answer 56

Fibronectin

Question 57

Fibronectin

Answer 57

Interacts with Collagen, binds to a specific class of integral protein called integrins

Question 58

ECM consists of mostly

Answer 58

Glycoproteins and protein fibres (collagen)

Question 59

Collagen is

Answer 59

Embedded in network of glycoproteins called proteoglycans.

Question 60

Proteoglycan complex: A) types of molecules B) what is molecule made of?

Answer 60

A) proteoglycan molecules B) carbohydrates and core protein