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Flashcards in LECTURE 14 Deck (54)
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1
Q

Is oxygen toxic and why ?

A

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

2
Q

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

A

Anaerobic and aerobic

3
Q

Anaerobic

A

O2 not used

4
Q

Aerobic

A

O2 used

5
Q

Obligate anaerobes

A

O2 is toxic

6
Q

Aerotolerant anaerobes

A

O is not used

7
Q

Facilitative anaerobes

A

Use O2 when its available

8
Q

Obligate aerobes

A

O2 is required/needed

9
Q

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

A

Use a secondary metabolic pathway

10
Q

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

A

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.

11
Q

Some prokaryotes that live in anaerobic conditions can perform

A

anaerobic respiration

12
Q

Two types of fermentation

A

1) alcohol fermentation

2) lactic acid fermentation

13
Q

Alcohol fermentation

A

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

used in brewing , winemaking and baking.

14
Q

Lactic acid fermentation

A

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.

15
Q

Cancer cells becomes more

A

Hypoxic

16
Q

Hypoxic

A

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.

17
Q

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

A

Grow even larger

18
Q

As tumours get larger, cells becomes more

A

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

19
Q

PET scans so what too track tumours

A

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

This is done is isotope Fluorine-18

20
Q

Which cells dont do fermentation

A

Nerve cells

21
Q

Why would a cell not do fermentation

A

The don’t have the necessary enzymes

22
Q

The cells that dont do fermentation :

A
  • 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
23
Q

A stoke is an

A

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

24
Q

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

A

Broken down to molecules that can enter glycolysis or Krebs cycle

25
Q

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

A

Amino acids

Pyruvate, acetyl CoA, and Krebs cycle

(Glycolysis and Krebs)

26
Q

Carbohydrates break down to ________ and enter ________

A

Sugars and enter glucose

glycolysis

27
Q

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

A

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

28
Q

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

A

molecular building blocks as needed

29
Q

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

A

Inhibited

30
Q

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

A

Inhibition of PFK

31
Q

Excess glucose can be

A

1) stored

2) used in other metabolic pathways to makes other required molecules

32
Q

AMP stimulates

A

PFK to be more active

33
Q

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

A

make more ATP by stimulating PFK (glycolysis)

34
Q

Citrate, the first product in the Krebs cycle, inhibits _____

  • citrate formation Is fed by ______
A

PFK. Glycolysis

35
Q

If citrate concentrations becomes to high, the

A

cell doesn’t need to make more

36
Q

Cell division in BOTH prokaryotes and eukaryotes include

A

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.

37
Q

Reproductive signals in prokaryotes (binary fission)

A

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

38
Q

The time required to divide is called

A

Doubling time or generation time

39
Q

Generation time is determined by :

A
  • type of organism
  • level of nutrients, wastes
  • temp
40
Q

A log plot of cell division shows it in a

A

theoretician situation with unlimited nutrients and no water build up.

Real growth is shown through exponential growth

41
Q

Lag phase

A
  • Little to no division occurring

- still have metabolic activity (growing in volume, synthesizing enzymes, proteins, RNA)

42
Q

Log phase

A
  • cells begin to divide
  • cell number doubles at a rate
  • use up nutrients and excretes waste products
43
Q

Stationary phase

A
  • metabolic rate of cells decrease

- cells die and divide at the same time

44
Q

Death phase

A
  • causes not always clear
  • cells lays due to damaged cell walls
  • toxicity of waste products
45
Q

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

A

Circular chromosome

46
Q

Ori

A

(Origin) : site on DNA molecules where replication begins

47
Q

Ter

A

(Terminus) : the site where replication ends

48
Q

Prior to cell division, the bacterial chromosome starts to

A

Duplicate

  • each daughter cell will recreate a fully copy
49
Q

Prokaryotic DNA synthesis occurs at the

A

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

50
Q

DNA segregation in prokaryotes

A
  • 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
51
Q

ParM involved in

A

Plasmid partitioning

52
Q

Cytokinesis in prokaryotes

A

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

53
Q

As the membrane pinches in, new cell wall materials are

A

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

54
Q

Septum

A

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