LECTURE 14

Question 1

Is oxygen toxic and why ?

Answer 1

Uses,it reacts with organic molecules (including DNA) casing them to function improperly.

Question 2

Organism. Can be placed in two categories with respect to O2

Answer 2

Anaerobic and aerobic

Question 3

Anaerobic

Answer 3

O2 not used

Question 4

Aerobic

Answer 4

O2 used

Question 5

Obligate anaerobes

Answer 5

O2 is toxic

Question 6

Aerotolerant anaerobes

Answer 6

O is not used

Question 7

Facilitative anaerobes

Answer 7

Use O2 when its available

Question 8

Obligate aerobes

Answer 8

O2 is required/needed

Question 9

Cecil are respiration produces a lot of ATP from glucose, but if O2 is unavailabe for cellular respiration, then the organism has to

Answer 9

Use a secondary metabolic pathway

Question 10

With out O2, there are tow ways to make ATP form organic molecules

Answer 10

1) continue to use electron transport chain, but use a different terminal e- acceptor (instead of O2)
2) use glycolysis to make ATP (doesn’t require O2). Oxidizing agent is NAD+, but without the e- transport chain, NADH will quickly build up. To continue, NAD+ will be regenerated.

Question 11

Some prokaryotes that live in anaerobic conditions can perform

Answer 11

anaerobic respiration

Question 12

Two types of fermentation

Answer 12

1) alcohol fermentation

2) lactic acid fermentation

Question 13

Alcohol fermentation

Answer 13

Pyruvate is converted to ethanol in 2 steps with release of CO2.

used in brewing , winemaking and baking.

Question 14

Lactic acid fermentation

Answer 14

Pyruvate is reduced by NADH, forming lactate as end product, without release of CO2

Makes cheese and yogurt

Muscle cells use this type off mere taint to generate ATP she O2 is scarce.

Question 15

Cancer cells becomes more

Answer 15

Hypoxic

Question 16

Hypoxic

Answer 16

Low oxygen, tumour grows it becomes more difficult for blood vessels to get O2 to the centre, becoming a site of lactic acid fermentation and glycolysis. Becomes primary source of ATP.

Question 17

Blood vessels may be stimulated to gorw into the tumour mass for cancer cells, allowing the tumour to

Answer 17

Grow even larger

Question 18

As tumours get larger, cells becomes more

Answer 18

efficient in importing glucose (glucose uptake correlates with poor prognosis)

Question 19

PET scans so what too track tumours

Answer 19

Trace glucose movement because cancer cells increase glycolysis and intake last of it

This is done is isotope Fluorine-18

Question 20

Which cells dont do fermentation

Answer 20

Nerve cells

Question 21

Why would a cell not do fermentation

Answer 21

The don’t have the necessary enzymes

Question 22

The cells that dont do fermentation :

Answer 22

• these are the first to die if deprived of O2
• cannot make ATP uncles O2 is present
• cannot maintain proper ion balance and membrane potential
• leads to cell damage, cessation of nerve function, death to organism

Question 23

A stoke is an

Answer 23

interruption of blood supply (oxygen) to a localized area in the brain, resulting in cell death

Question 24

All offs can be used as a source of energy IF they can be

Answer 24

Broken down to molecules that can enter glycolysis or Krebs cycle

Question 25

Proteins break down into _____ which can enter _______ ________ and ___________

Answer 25

Amino acids Pyruvate, acetyl CoA, and Krebs cycle (Glycolysis and Krebs)

Question 26

Carbohydrates break down to ________ and enter ________

Answer 26

Sugars and enter glucose | glycolysis

Question 27

Fats break down to ____and ______ and enter into ______ and _________

Answer 27

Fats break down to glycerol and fatty acids and enter into glyceraldehyde-3- and acetyl CoA

Question 28

Cells can also siphon off intermediates form glycolysis and krebs to use as

Answer 28

molecular building blocks as needed

Question 29

PFK activity is _________ allosterically by high levels of ATP in cells

Answer 29

Inhibited

Question 30

If cells generate more ATP the they can use, they prevent/slow glycolysis by

Answer 30

Inhibition of PFK

Question 31

Excess glucose can be

Answer 31

1) stored | 2) used in other metabolic pathways to makes other required molecules

Question 32

AMP stimulates

Answer 32

PFK to be more active

Question 33

As ATP is used, and AMP accumulates, this signals the cell to

Answer 33

make more ATP by stimulating PFK (glycolysis)

Question 34

Citrate, the first product in the Krebs cycle, inhibits _____ - citrate formation Is fed by ______

Answer 34

PFK. Glycolysis

Question 35

If citrate concentrations becomes to high, the

Answer 35

cell doesn’t need to make more

Question 36

Cell division in BOTH prokaryotes and eukaryotes include

Answer 36

1) a reproductive signal that tells cell when to divide (can be inside or outside of cell) 2) DNA replication: each daughter cells relieves copy of DNA 3) DNA segregation: replicated DNA gets distributed to new cells 4) Cytogenesis: each new cells has cell membrane and cell wall if parents has one.

Question 37

Reproductive signals in prokaryotes (binary fission)

Answer 37

They sense their environment and respond by alternating their cellular functions.

Question 38

The time required to divide is called

Answer 38

Doubling time or generation time

Question 39

Generation time is determined by :

Answer 39

- type of organism - level of nutrients, wastes - temp

Question 40

A log plot of cell division shows it in a

Answer 40

theoretician situation with unlimited nutrients and no water build up. Real growth is shown through exponential growth

Question 41

Lag phase

Answer 41

- Little to no division occurring | - still have metabolic activity (growing in volume, synthesizing enzymes, proteins, RNA)

Question 42

Log phase

Answer 42

- cells begin to divide - cell number doubles at a rate - use up nutrients and excretes waste products

Question 43

Stationary phase

Answer 43

- metabolic rate of cells decrease | - cells die and divide at the same time

Question 44

Death phase

Answer 44

- causes not always clear - cells lays due to damaged cell walls - toxicity of waste products

Question 45

In all prokaryotes, the genetic info is contained in a single

Answer 45

Circular chromosome

Question 46

Ori

Answer 46

(Origin) : site on DNA molecules where replication begins

Question 47

Ter

Answer 47

(Terminus) : the site where replication ends

Question 48

Prior to cell division, the bacterial chromosome starts to

Answer 48

Duplicate - each daughter cell will recreate a fully copy

Question 49

Prokaryotic DNA synthesis occurs at the

Answer 49

same time as other metabolic process in the life cycle, unlike eukaryotes, which separate DNA replication form other stages of life.

Question 50

DNA segregation in prokaryotes

Answer 50

- before DNA is replicated, it is distributed throughout the cytosol - immediately after DNA starts to replicate, dynamic actin like protein subunits bind to a region next to the ori and form filaments that help separate the two replicating nucleotides as they finish replication - ParM

Question 51

ParM involved in

Answer 51

Plasmid partitioning

Question 52

Cytokinesis in prokaryotes

Answer 52

FtsZ proteins form a ring that pinches cell membrane inwards until cytosol separates

Question 53

As the membrane pinches in, new cell wall materials are

Answer 53

deposited in the plane of the FtsZ ring (septum) which finally separated into two new cells

Question 54

Septum

Answer 54

The new barrier that forms when the FtsZ ring pinches during cytokinesis in prokaryotes