Quiz Questions For Metabolism

Front 1

List 4 similarities between the citric acid cycle and beta oxidation.

Back 1

1) cycles only occur under aerobic conditions

2) both occur entirely only in the mitochondria

3)at least some intermediates are processed as coenzyme-A thioesters

4)hydrogen is extracted from a C-C single bond to yield a C=C double bond using FAD as the cosubstrate

Front 2

What amino acids can be degraded to energy-rich metabolites?

Back 2

All standard amino acids can be degraded in human metabolism.

Front 3

The sulfonylurea receptor is a __________ that mediates __________. When activated by its ligand, it causes ___________. The receptor and its associated ion channel are controlled by ________.

Back 3

- a membrane protein associated with a potassium ion channel

-mediates secretion of insulin

-when activated it causes the cell membrane to depolarize

-the receptor & the ion channel are controlled by ATP; high levels of ATP lowers the permeability of the ion channel

Front 4

The rate of insulin secretion is _________ when blood glucose is high.

Back 4

The rate of insulin secretion is high when blood glucose is high.

Front 5

The key energy-rich compound in human energy metabolism is ____.

Back 5

ATP (adenosine triphosphate)

Front 6

Carbon atoms that are oxidized in the TCA may enter it as _____ or _____.

Back 6

acetyl-CoA or in the form of TCA intermediates

Front 7

Acetyl-CoA is formed in the following reaction:

_____ + _____ --> 2 acetyl-CoA

This is catalyzed by _______.

Back 7

acetoacetyl-CoA + coenzyme A --> 2acetyl-CoA

thiolase

Front 8

Beta-oxidation produces substrates for _______.

Back 8

the citric acid cycle because fatty acids are broken down to Acetyl-CoA

Front 9

Aspartate is a precursor for __________ in the _____ cycle.

Back 9

ornithine

urea cycle

Front 10

Glucogenic amino acids can be degraded to _______ or an intermediate in the _______ Cycle.

Back 10

pyruvate

Krebs cycle

Front 11

Ketogenic amino acids produce ketones when energy sources are low: some are degraded directly to _________ such as _______, or converted to acetyl CoA.

Back 11

- ketone bodies such as acetoacetate that can be used as fuel in the brain and muscle

Front 12

Acetacetate cannot be used in __________, since acetyl CoA cannot be converted directly to __________.

Back 12

-gluconeogenesis

-cannot be converted directly to oxaloacetate.

Front 13

In humans,some examples of glucogenic amino acids are ...?

2 ketogenic amino acids?

Both keto and glucogenic?

Back 13

-serine, arginine, cysteine, proline, glutamate, aspartate

-lysine & leucine

-phenylalanine threonine, isoleucine,tryptophan and tyrosine

Front 14

Ketogenic amino acids produce ketones when energy sources are low: some are degraded directly to _________ such as _______, or converted to acetyl CoA.

Back 14

- ketone bodies such as acetoacetate that can be used as fuel in the brain and muscle

Front 15

Acetacetate cannot be used in __________, since acetyl CoA cannot be converted directly to __________.

Back 15

-gluconeogenesis

-cannot be converted directly to oxaloacetate.

Front 16

In humans,some examples of glucogenic amino acids are ...?

2 ketogenic amino acids?

Both keto and glucogenic?

Back 16

-serine, arginine, cysteine, proline, glutamate, aspartate

-lysine & leucine

-phenylalanine threonine, isoleucine,tryptophan and tyrosine

Front 17

Cholesterol and sunlight can form _____.

Back 17

Vitamin D.

Front 18

What is the precursor to bile salts and steroid hormones?

Back 18

Cholesterol.

Front 19

What happens when a person fasts (low carbohydrate diet or high fat)?

Back 19

Malonyl CoA (synthesis) decreases and in turn Carnitine transferase (oxidation) activity increases

oxaloacetate increasingly used for gluconeogenesis since no glycolytic energy demands. Thus TCA cycle slows, meaning Citrate concentration will decrease and Acetyl CoA will accumulate.

Alternative uses for Acetyl CoA begin including production of ketone bodies and thier increased use in the brain. Ketone production increases found in urine and result in urine acidosis and loss of Na ions.

Front 20

Acetyl-CoA carboxylase is _____ by citrate and ______ by epinephrine.

Back 20

activated by citrate

inhibited by epinephrine

Front 21

Beta oxidation occurs in the _________, while fatty acid synthesis mostly occurs in ________.

Back 21

beta-oxidation in the mitochondria

FA synthesis in the cytoplasm

The acetyl CoA is inside the mitochondria and must be shuttled out of the mitochondria for fatty acid synthesis

Front 22

If DNA was replicated in a conservative way Meselson and Stahl's experiment would have had a different result. They would have found _____ bands inthe ______ generation.

Back 22

two bands in the first and second generation

Front 23

The Meselson-Stahl experiment was an experiment by Matthew Meselson and Franklin Stahl which demonstrated that DNA replication was _______ .

Back 23

semiconservative

Front 24

Semiconservative replication means

Back 24

when the double stranded DNA helix was replicated, each of the two double stranded DNA helices consisted of one strand coming from the original helix and one newly synthesized

Front 25

During DNA replication nucleotides are added to to the growing chain at the

Back 25

OH group at the 3' end

Front 26

The enzymes that stabilize the DNA fork upstream during replication are called

Back 26

gyrases

Front 27

Okazaki fragments are

Back 27

short fragment of DNA (with an RNA primer at the 5' terminus) found on the lagging strand

Front 28

bidirectional replication is ______ in eukaryotes and prokaryotes?

Back 28

the same

Front 29

A mutational change in the third base of a codon is unlikely to make a change in the resulting amino acid sequence because of

Back 29

the degeneracy of the code

Front 30

post-transcriptional processing in eukaryotes

Back 30

5' end cut and 7mG cap added

introns excised and exons spliced together

3' end cut at AAUAA

Front 31

Ames test is _______ to assess the _________ of chemical compounds.

Back 31

a biological assay using Salmonella typhimurium that carry mutations in genes involved in histidine synthesis; require histidine for growth

mutagenic potential

Front 32

The tester strains used in the Ames test are specially constructed

Back 32

to have both frameshift and point mutations in the genes required to synthesize histidine

Front 33

What is the variable being tested in the Ames test?

Back 33

the mutagen's ability to cause a reversion to growth on a histidine-free medium

Front 34

How do you conduct the Ames test?

Back 34

bacteria spread on agar plate with small amount of histidine - allows the bacteria to grow and have the opportunity to mutate; when histidine is depleted only bacteria mutated to gain the ability to produce histidine survive

plate incubated for 48 hours

mutagenicity of substance proportional to number of colonies observed

Front 35

One strategy that eukaryotic organisms have evolved to supply cells with lots of ribosomes during periods of heavy protein synthesis is to have

Back 35

many repeats of rRNA genes in the genome

Front 36

Where on the ribosome will the first charged tRNA with the anticodon UAC attach?

Back 36

P site of the small subunit

Front 37

For a new mutation to be important in the evolution of an organism (to give an organism a selective advantage in it's phenotype). The mutation must be

Back 37

in the gametic cell line

Front 38

If a single mutation causes several amino acids in a protein to change it is probably going to be a

Back 38

frameshift mutation

Front 39

do not result in a change to the amino acid sequence of a protein; may occur in non-coding region (outside of a gene or within an intron), or within an exon but w'out altering the final amino acid sequence

Back 39

silent mutation

Front 40

single base substitution, is a type of mutation that causes the replacement of a single base nucleotide with another nucleotide

Back 40

point mutation (transitions & transversions)

Front 41

replacement of a purine base with another purine or replacement of a pyrimidine with another pyrimidine

Back 41

transitions

Front 42

replacement of a purine with a pyrimidine or vice versa

Back 42

transversions

Front 43

point mutations, code for a stop, which can truncate the protein

Back 43

nonsense mutations:

Front 44

more common than

Back 44

Transition mutations are about an order of magnitude __________ transversions.

Front 45

point mutations, code for a different amino acid

Back 45

missense mutations

Front 46

what mutation causes sickle-cell disease?

Back 46

sickle-cell disease is caused by a single point mutation (a missense mutation) in the beta-hemoglobin gene that converts a GAG codon into GTG, which encodes the amino acid valine rather than glutamic acid.

Front 47

Which is the main enzyme involved in E. coli DNA replication?

Back 47

DNA Polymerase III

Front 48

The presence of nucleosomes complicates ______ in eukaryotes.

Back 48

RNA transcription

Front 49

Eukaryotes have more kinds of ______ than prokaryotes.

Back 49

RNA polymerase

Front 50

There are more _____ involved in the gene expression of eukaryotic genes than prokaryotic genes

Back 50

receptors

Front 51

Somatic mutations are expressed only if they are ______.

Back 51

dominant

Front 52

Somatic mutations are _______ from generation to generation.

Back 52

not passed down

Front 53

Gametic mutations are ____ compared to somatic mutations.

Back 53

rare

Front 54

This sequence is likelly to form pyrimidine dimers & cause a mutation in subsequent generations of DNA

Back 54

C-C

Front 55

When the lac operon is transcribed, RNA polymerase initially interacts with a stretch of DNA called the

Back 55

promoter

Front 56

When lactose is present in E.coli it binds to the

Back 56

repressor molecule

Front 57

A merodiploid is formed with an F plasmid that carries the complete lac operon. The bacterial genome carries a constitutive mutation in the lac operon operator. Will there be beta galactosidase activity if lactose is absent?

Back 57

Yes, because the mutation in the bacterial operator will cause transcription to occur all the time.

Front 58

type of eukaryotic regulatory molecules have regions that interacts with DNA

Back 58

activators

Front 59

types of of DNA-binding protein domain

Back 59

helix-turn-helix region

leucine zipper

zinc finger

Front 60

Alkaptonuria is caused by a build-up of

Back 60

homogentisic acid

Front 61

Wildtype Neurospora crassa that can grow on minimal media are called

Back 61

prototrophic

Front 62

The mutational change that produces the abnormal beta globin molecule and causes the disease sickle-cell aneamia could be described as a

Back 62

missense mutation

Front 63

The most common CF mutation, causes the abnormal gene product to

Back 63

get stuck in the endoplasmic reticulum and never reach the cell membrane

Front 64

The most common mutational change that creates a CF allele could be described as a

Back 64

deletion

Front 65

The trp operon is

Back 65

a repressible, negatively controlled operon

Front 66

RNA polymerase in eukaryotes combines with the ______.

Back 66

basal factors

Front 67

Allele frequencies for a gene with two alleles can be calculated from a population that is not in H-W equilibrium if

Back 67

heterozygotes have a distinctive phenotype

Front 68

assumptions of H-W equilibrium

Back 68

Large population size
Random mating
No migration