Chapter 6 flashcards

Question 1

What do Autotrophs do?

Answer 1

Make CO2 into their organic carbon supply (AKA, sugars, lipids,proteinsandnucleicacids)

Question 2

3 Things all cells need for metabolism

Answer 2

1) A carbon source
2) A source of energy
3) A source of electrons or hydrogen atoms

Question 3

Heterotrophs relies on?

Answer 3

They rely on autotrophs in the food chain to make their organic C source

Question 4

Organisms that utilize an inorganic source of carbon (that is, carbon dioxide) as their sole source of carbon are called?

Answer 4

Autotrophs, so named because they “feed” themselves

Question 5

Autotrophs make organic compounds from?

Answer 5

CO2 & thus need not acquire carbon from organic compounds from other organisms

Question 6

Catabolize reduced organic molecules (such as proteins, carbohydrates, amino acids, & fatty acids) they acquire from other organisms

Answer 6

Heterotrophs

Question 7

Carbon fixation allows a?

Answer 7

Food chain including heterotrophs

– PRIMARY PRODUCERS

Question 8

What are chemotrophs?

Answer 8

Organisms that acquire energy from redox reactions involving inorganic & organic chemicals

Question 9

Phototrophs are?

Answer 9

Organisms that use light as their energy source

Question 10

Lithotrophs get e- from?

Answer 10

Inorganic sources.

• Photoautotrophs
• Chemoautotrophs

Question 11

Organisms can be categorized based on their carbon & energy sources into one of four basic groups

Answer 11

1) Photoautotrophs
2) Chemoautotrophs
3) Photoheterotrophs
4) Chemoheterotrophs

Question 12

Plants, some protozoa, and algae are?

Answer 12

Photoautotrophs

Question 13

Animals, fungi, and other protozoa are?

Answer 13

Chemoheterotrophs

Question 14

Members in all four groups?

Answer 14

Bacteria & archaea

Question 15

The most common chemical elements in cells

Answer 15

Hydrogen

Question 16

Never a limiting agent

Answer 16

Hydrogen because it is so common in organic molecules and water

Question 17

Hydrogen is essential for?

Answer 17

Hydrogen bonding and electron transfer

Question 18

Heterotrophs acquire electrons (typically as part of hydrogen atoms) from the same organic molecules that provide them carbon and are called?

Answer 18

Organotrophs

Question 19

Organotrophs get e- from?

Answer 19

Organic sources

• Photoheterotrophs
• Chemoheterotrophs

Question 20

Sunlight for energy; CO2 as carbon source

- Called primary producers (Plants)

Answer 20

Photoautotrophs

Question 21

Inorganic compounds (H2S) for energy; use CO2 as carbon source

Answer 21

Chemoautotrophs

Question 22

Sunlight for energy; organic compounds as carbon source

Answer 22

Photoheterotrophs

Question 23

Organic compounds for energy and as carbon source

Answer 23

Chemoheterotrophs

Question 24

Lithotrophs are?

Answer 24

Autotrophic organisms that acquire electrons or hydrogen atoms from inorganic molecules such as H2, No2-, H2S, and Fe2+

Question 25

Oxygen is essential for _______ ________ because it serves as the final electron acceptor of electron transport chains, which produce most of the ATP in these organisms

Answer 25

obligate aerobes

Question 26

Oxygen is a deadly poison for?

Answer 26

Obligate anaerobes

Question 27

The toxic forms of O2 are those that are?

Answer 27

Highly reactive

Question 28

There are 4 toxic forms of O2

Answer 28

1) Singlet oxygen (102) 2) Superoxide radical (O2-) 3) Peroxide anion (022-) 4) Hydroxyl radical (OH)

Question 29

Molecular oxygen w/electrons that have been boosted to a higher energy state, typically during aerobic metabolism. Very reactive oxidizing agent. Phagocytic cells use it to oxidize pathogens. Also photochemically produced by the reaction of oxygen & light, phototrophic microorganisms often contain pigments called carotenoids that prevent toxicity by removing the excess energy of these

Answer 29

Singlet oxygen (1O2)

Question 30

A few of these form during the incomplete reduction of O2 during electron transport in aerobes & during metabolism by anaerobes in the presence of O2. So reactive & toxic that aerobic organisms must produce enzymes to detoxify them

Answer 30

Superoxide radical (O2-)

Question 31

These enzymes, which have active sites that contain metal ions, depending on the organism- combine two superoxide radicals & two protons to form hydrogen peroxide & molecular oxygen

Answer 31

Superoxide dismutases

Question 32

Hydrogen peroxide formed during reactions catalyzed by superoxide dismutase (and during other metabolic reactions) contains ______ _____, another highly reactive oxidant. It is this that makes hydrogen peroxide an antimicrobial agent. Aerobes contain either catalase or peroxidase, enzymes that detoxify this.

Answer 32

Peroxide anion (O22-)

Question 33

Catalase converts hydrogen peroxide to?

Answer 33

Water & molecular oxygen

Question 34

Breaks down hydrogen peroxide without forming oxygen, using a reducing agent such as the coenzyme NADH

Answer 34

Peroxidase

Question 35

Obligate anaerobes either lack both catalasse and peroxidase or have only a small amount of them, so they are susceptible to the toxic action of?

Answer 35

Hydrogen peroxide

Question 36

These result from ionizing radiation & from the incomplete reduction of hydrogen peroxide. The most reactive of the 4 toxic forms of O2, but because hydrogen peroxide does not accumulate in aerobic cells, the threat of this is virtually eliminated in aerobic cells

Answer 36

Hydroxyl radical (OH)

Question 37

Not all organisms are either strict aerobes or anaerobes; many can live in various oxygen concentrations between these two extremes. Some aerobic organisms can maintain life via fermentation or anaerobic respiration, though their metabolic efficiency is often reduced in the absence of O2. Such organisms are called?

Answer 37

Facultative anaerobes. E. coli is an example

Question 38

These do not use aerobic metabolism, but they tolerate O2 by having some of the enzymes that detoxify O2's poisonous forms

Answer 38

Aerotolerant anaerobes

Question 39

Ulcer causing pathogen

Answer 39

Helicobacter pylori

Question 40

This concentration of O2 is found in the stomach. They are damaged by the 21% concentration of O2 in the atmosphere. Requires O2 levels of 2% to 10%.

Answer 40

Microaerophiles

Question 41

Algae, most fungi & protozoa, and many prokaryotes have what type of O2 requirements?

Answer 41

Obligate aerobes

Question 42

A few yeasts & numerous prokaryotes have what type of O2 requirements?

Answer 42

Facultative anaerobes

Question 43

Many prokaryotes and a few protozoa have what type of O2 requirements?

Answer 43

Aerotolerant, microaerophilic, or obligate anaerobes

Question 44

Why are temperatures important?

Answer 44

Because they have an effect on the three-dimensional configurations of biological molecules. To function properly, proteins require a specific three-dimensional shape that is determined in part by temperature-sensitive hydrogen bonds, which are more likely to form at lower temps. and break at higher temps. Lipids are also temp. sensitive, if temp is too low membranes become rigid & fragile; if temp. is too high lipids become too fluid

Question 45

When hydrogen bonds break in proteins what happens?

Answer 45

They denature and lose function

Question 46

The lowest temperature at which an organism is able to conduct metabolism is called the?

Answer 46

Minimum growth temperature. Microbes (particularly bacteria) can survive at temps. far below this.

Question 47

The highest temperature at which an organism continues to metabolize is called the?

Answer 47

Maximum growth temperature. When an organism exceeds this value, its proteins are permanently denatured, & it dies

Question 48

The temperature at which an organism's metabolic activities produce the highest growth rate is the?

Answer 48

Optimum growth temperature

Question 49

Based on their preferred temperature ranges- the temperatures w/in which their metabolic activity and growth are best supported- microbes can be categorized into four overlapping groups

Answer 49

1) Psychrophiles- Below 15 degrees C & continue to grow at temps. below 0 degrees C 2) Mesophiles- 20-40 degrees C 3) Thermophiles- Above 45 Degrees C 4) Hyperthermophiles- Above 80-100 Degrees C

Question 50

Process in which a cell grows to twice its normal size and divides in half to produce two daughter cells of equal size

Answer 50

Binary fission

Question 51

Steps of binary fission

Answer 51

1) Cell replicates chromosome (DNA molecule) & attaches to cytoplasmic membrane 2) Elongation, growth between attachment sites pushes chromosome apart 3) Forms new cytoplasmic membrane & wall (septum) across midline 4) Septum completed daughter cells may stay attached or separate. When attached, further binary fission in parallel lines produces a chain. When divisions are in diff. planes cell becomes a cluster 5) Process repeats

Question 52

log means

Answer 52

Logarithmic

Question 53

In a log scale, each division is ___ times longer than the preceding one

Answer 53

10

Question 54

During the lag phase the cells are?

Answer 54

Adjusting to their new environment; most don't reproduce immediately instead synthesis enzymes to utilize novel nutrients in medium. Can last less than an our for for days depending on the species & chemical & physical conditions of medium

Question 55

What happens during the log phase?

Answer 55

Rapid chromosome replication, growth, and reproduction. Reproductive rates reaches a constant as DNA and protein syntheses are maximized. Preferred for industrial & lab purposes

Question 56

Populations in which phase of microbial growth are susceptible to antimicrobial drugs?

Answer 56

Log phase

Question 57

What is the stationary phase

Answer 57

As nutrients are depleted & wastes accumulate, rate of reproduction decreases. Number of dying cells equals number be reproduced, size of population constant. Metabolic rate of surviving cells declines

Question 58

What is the death phase?

Answer 58

If nutrients aren't added & wastes aren't removed, the population reaches point where cells die faster than they are produced. Decline phase. Some remain alive & continue metabolizing & reproducing

Question 59

Photoautotrophs use?

Answer 59

Carbon dioxide as a carbon source and light energy to make their own food

Question 60

Chemoautotrophs use?

Answer 60

Carbon dioxide as a carbon source but catabolize organic molecules for energy

Question 61

Photoheterotrophs are?

Answer 61

Photosynthetic organisms that acquire energy from light & acquire nutrients via catabolism of organic compounds

Question 62

Chemoheterotrophs use?

Answer 62

Organic compounds for both energy and carbon

Question 63

Organotrophs acquire?

Answer 63

Electrons for redox reactions from organic sources

Question 64

Lithotrophs acquire electrons from?

Answer 64

inorganic sources

Question 65

From coldest to warmest temperature requirements

Answer 65

Psychrophiles, mesophiles, thermophiles, or hyperthermophiles

Question 66

Superoxide dismutase

Answer 66

Detoxifies superoxide radicals

Question 67

The most reactive of the four toxic forms of oxygen is?

Answer 67

The hydroxyl radical

Question 68

Microaerophiles that grow best with a high concentration of carbon dioxide in addition to a low level of oxygen are called?

Answer 68

Capnophiles