microbiology exam 2

Question 1

Metabolism

Answer 1

Pertains to all chemical and physical workings of the cell.

Question 2

Anabolism

Answer 2

Any process that results in synthesis of cell molecules and structures.
A building and bond-making process that forms larger macromolecules from smaller ones.
Requires the input of energy.

Question 3

Catabolism

Answer 3

Breaks the bonds of larger molecules into smaller molecules.
Releases energy.

Question 4

Enzymes

Answer 4

Serve as a physical site upon which a substrate can be positioned for various reactions.
Larger in size than substrate.
Presents a unique active site that matches only that particular substrate.
Binds substrate.
Not used up by the reaction.
Can be reused.

Question 5

Holoenzyme

Answer 5

Complete functional enzymes, a combination of a protein and one or more cofactor.

Question 6

Apoenzyme

Answer 6

Protein portion of a holoenzyme.

Question 7

Cofactors

Answer 7

Either organic molecules called coenzymes or inorganic elements (metal ions).

Question 8

Enzyme-Substrate interaction

Answer 8

Described as “lock and key” fit.
Bond formed between the substrate and enzyme is weak and easily reversible.
A reaction occurs once the enzyme-substrate complex has formed…. Product is formed and released.
Enzymes can attach to another substrate molecule and repeat this action.

Question 9

Many cofactors are derived from…

Answer 9

Vitamins

Question 10

Examples of cofactors…

Answer 10

Iron, copper, magnesium, manganese, zinc, cobalt, selenium, etc.

Question 11

Changes in normal conditions cause enzymes to be…

Answer 11

Unstable or Labile.

Question 12

Activity of enzymes by the cells environment

Answer 12

Natural temperature
pH
Osmotic pressure

Question 13

Denaturation

Answer 13

Weak bonds that maintain the native shape of the apoenzyme are broken.
Causes distortion of the enzymes shape & prevents the substrate from attaching to the active site.

Question 14

Competitive inhibition

Answer 14

Inhibits enzyme activity by supplying a molecule that resembles the enzyme’s normal substrate.
“Mimic” occupies the active site, preventing the actual substrate from binding.

Question 15

Noncompetitive inhibition

Answer 15

Enzymes have two binding sites… the active site and a regulatory site (allosteric site).
Molecules bind to the regulatory site.
Slows down enzymatic activity once a certain concentration of product is reached.

Question 16

Enzyme repression

Answer 16

Genetic apparatus responsible for replacing enzymes is automatically suppressed.

Question 17

Enzyme induction

Answer 17

Enzymes appear only when suitable substrates are present.

Question 18

Metabolic pathways

Answer 18

Often occur in multi step series or pathway, with each step catalyzed by an enzyme.
Product of one reaction is often the reactant for the next, forming a linear chain of reactions.
They do not stand alone; interconnected and merge at many sites.

Question 19

Energy is mostly stored as…

Answer 19

ATP

Question 20

Exergonic reactions

Answer 20

Releases energy as it goes forward.

Question 21

Endergonic reactions

Answer 21

Require the input of energy.

Question 22

Exergonic and endergonic reactions are often

Answer 22

Coupled so that released energy is immediately put to use.

Question 23

Energy released during Exergonic reactions is stored in

Answer 23

High energy phosphate bonds in ATP.

Question 24

Oxidation

Answer 24

Loss of electrons.

Question 25

Reduction

Answer 25

Gain of electrons.

Question 26

Oxidation-reduction reactions

Answer 26

Common in the cell and are indispensable to the required energy transformations.

Question 27

Oxidoreductases

Answer 27

Enzymes that remove electrons from one substrate and add them to another. Their coenzyme carriers are NAD and FAD.

Question 28

Redox pair

Answer 28

An electron donor and an electron acceptor involved in a redox reaction.

Question 29

Dehydrogenation

Answer 29

Removal of hydrogens from a compound during a redox reaction.

Question 30

Reducing power

Answer 30

Electrons available in NADH and FADH2.

Question 31

Energy

Answer 31

Stored in the bonds of ATP.

Question 32

Aerobic respiration

Answer 32

A series of reactions that converts glucose to CO2 and allows the cell to recover significant amounts of energy. Utilizes glycolysis, Kreb’s cycle, and the respiratory chain. Relies on free oxygen as the final electron and hydrogen acceptor. Characteristic of many bacteria, fungi, Protozoa, and animals.

Question 33

Anaerobic respiration

Answer 33

Used by strictly anaerobic organisms and others who are able to metabolize with or without oxygen. Involves the same three pathways as aerobic respiration: glycolysis, Krebs cycle, and the electron transport chain.

Question 34

Fermentation

Answer 34

Incomplete oxidation of glucose. Oxygen is not required. Organic compounds are terminal electron acceptors.

Question 35

NADH and FADH2

Answer 35

Carry a lot of energy during electron transport (respiratory chain).

Question 36

Oxidative phosphorylation

Answer 36

The coupling of ATP synthesis to electron transport. NADH can give rise to 3 ATPS FADH2 produces 2 ATPS

Question 37

Products of fermentation

Answer 37

Alcoholic beverages Solvents Organic acids Vitamins Antibiotics Hormones Large-scale industrial processes Amino acid production

Question 38

Fatty acids undergo

Answer 38

Beta oxidation

Question 39

The product of fatty acids after beta oxidation that can enter the Krebs cycle…

Answer 39

Acetyl-CoA

Question 40

Proteins are broken down into amino acids by

Answer 40

Proteases

Question 41

Amino groups are removed through

Answer 41

Deamination

Question 42

Amphibolism

Answer 42

The ability of a system to integrate catabolic and anabolic pathways to improve cell efficiency.

Question 43

Polysaccharides are predominant components of

Answer 43

Capsules and glycocalyx

Question 44

Proteins

Answer 44

Account for a large proportion of a cell’s constituents. Essential components of enzymes, cytoplasmic membrane, cell wall, and cell appendages. 20 amino acids are needed to make these proteins.

Question 45

Nucleic acid

Answer 45

DNA and RNA responsible for the hereditary continuity of cells and the overall direction of protein synthesis.

Question 46

Genetics

Answer 46

The study of inheritance or hereditary of living things. It explores the transmission of biological traits from parent to offspring, how those traits are expressed in an organism, the structure and function of the genetic material, and how this material changes (mutation).

Question 47

Genome

Answer 47

The sum total of genetic material of an organism. Most of the genome exists in the form of chromosomes. Some appear as plasmids, mitochondria, or chloroplasts. Composed exclusively of DNA

Question 48

Genome of viruses

Answer 48

Can contain either DNA or RNA NOT BOTH AT ONCE!!!!!!!!!!

Question 49

Chromosome

Answer 49

A distinct cellular structure composed of a neatly packaged DNA molecule

Question 50

Eukaryotic chromosomes

Answer 50

DNA wound around histone proteins Located in the nucleus Diploid (in pairs) OR Haploid (single) Linear in appearance

Question 51

Bacterial chromosomes

Answer 51

DNA is condensed into a packet of histone-like proteins One, two, or sometimes several chromosomes Typically one (HAPLOID) and no nucleus

Question 52

Structural genes

Answer 52

Code for proteins Regulatory genes that control gene expression

Question 53

Genotype

Answer 53

The sum of all gene types An organisms distinctive genetic makeup

Question 54

Phenotype

Answer 54

The expression of the genotype creates traits (structures or functions)