๐Ÿท๏ธ LIMITED TIME OFFER: GET 20% OFF GRADE+ YEARLY SUBSCRIPTION โ†’
Log in
Biology
2
answers
0
watching
83
views

Enzymes are long proteins, usually containing more than100 amino acids, yet the active site contains only a few aminoacids. Which amino acids appear most frequently in active sites ofenzymes? Explain why the other amino acids of the chain are presentand what would happen to the activity if the enzyme's structurewere changed significantly.

Watch
2
answers
0
watching
83
views

For unlimited access to Homework Help, a Homework+ subscription is required.

Unlock all answers

Get 1 free homework help answer.
Already have an account? Log in
Share
Jarrod Robel
Jarrod RobelLv2
28 Sep 2019
Already have an account? Log in
Share

Related textbook solutions

Molecular Cell Biology
8 Edition,
Lodish
ISBN: 9781464183393
Biology: Science for Life with Physiology
6 Edition,
Belk
ISBN: 9780134555430
Concepts of Biology
OER Edition,
Openstax
ISBN: 9781938168116
Biology
2nd Edition, 2013
Openstax
ISBN: 9781947172517
Essentials of Biology
5 Edition,
Mader
ISBN: 9781259660269

Related questions

1. The active site of an enzyme usually consists of a pocket on the enzyme surface lined with the amino acid side chains necessary to bind the substrate and catalyze its chemical transformation. Carboxypeptidase, which sequentially removes the carboxyl-terminal amino acid residues from its peptide substrates, consists of a single chain of 307 amino acids. The two essential catalytic groups in the active site are furnished by Arg145 and Glu270 .

a. How many amino acid residues apart are these two amino acids?

b. Explain how it is that these two amino acids, so distantly separated in the sequence, can catalyze a reaction occurring in the space of a few tenth of a nanometer?

c. If only these two catalytic groups are involved in the mechanism of hydrolysis, why is it necessary for the enzyme to contain such a large number of aa residues?

2. What level of protein structure would be disrupted by the following below

a. heat

b. strong acid

c. saturated salt solution

d. organic solvents such as alcohol and chloroform

(BIOCHEMISTRY QUESTION)

A. Gluconeogenesis is not just the reverse of glycolysis. Briefly describe one of the steps catalyzed by different enzymes in glycolysis and gluconeogenesis.

B. Explain how a biochemist might dicover that a certain enzyme is allosterically regulated.

C. What are the regulatory implications for the cell with regard to ATP & AMP, given the relative concentrations of ATP & AMP in a cell?

D. Describe the function of fructose 2,6-bisphosphate in overriding the control of gycolysis and gluconeogenesis in liver cells in response to lowered blood glucose levels.

E. The human disease beriberi is caused by a deficiency of thiamine in the diet. People with severe beriberi have higher than normal levels of pyruvate in their blood & urine. Explain this observation in terms of specific enzymatic reaction(s).

My Responses: Could you tell me if these are correct? If not, could you provide the correct answer and explanation?

A. Its a cellular process in which glucose is produced from pyruvate, amino acids, lactate, and other biogenic precursors.

B. They might learn that an enzyme is allosterically regulated if that protein or enzyme undergoes a conformational change modulated by the binding of one or more modulators/effectors to alternate sites on the protein, resulting in a change in its activity. And they usually have more than one polypeptide chain.

C. The regulatory implications for the cell would be that all activity would increase and concentrations would go up unless bound to PFK-1 and then the overall activity would drop.

D. Low blood glucose is when glucagon signals the liver to produce and release more glucose (gluconeogenesis) and stop consumption. Fructose 2, 6-bisphosphate mediates rapid hormonal regulation of glycolysis and gluconeogenesis.

E. Pyruvate is the product of both carbohydrate and amino acid catabolism that enters cellular respiration in the mitochondria when converted to acetyl-CoA catalyzed by the PDH complex. The first step in the PDH complex reaction is a decarboxylation reaction that cannot be catalyzed without the enzyme thiamine pyrophosphate (TPP). This coenzyme is a derivative of thiamine or vitamin B1.

Question 1

Not yet answered

Marked out of 1.00

Flag question

Question text

The function of tRNA is to

Select one:

a. provide a site for polypeptide synthesis

b. transport amino acids to the ribosome

c. transcribe DNA

d. transform DNA

Question 2

Not yet answered

Marked out of 1.00

Flag question

Question text

The lipid bi-layer is

Select one:

a. hydrophilic

b. hydrophobic

c. hydrophilic and hydrophobic

d. depends on the surrounding medium

Question 3

Not yet answered

Marked out of 1.00

Flag question

Question text

Which of the following statements is FALSE?

Select one:

a. carbohydrates are generally hydrophilic molecules.

b. living things use carbohydrates for structure and for energy storage.

c. carbohydrates are composed principally of carbon, hydrogen, and oxygen.

d. none of the above รขย€ย“ they are all true

Question 4

Not yet answered

Marked out of 1.00

Flag question

Question text

Which of the following terms correctly describes a compound featuring more than one double bond?

Select one:

a. saturated

b. polyunsaturated

c. monounsaturated

d. disaturated

Question 5

Not yet answered

Marked out of 1.00

Flag question

Question text

Eukaryotic mRNA transcripts are protected from modification by

Select one:

a. 5' caps

b. 5' poly-A caps

c. 3' caps

d. 5'-3' poly tails

Question 6

Not yet answered

Marked out of 1.00

Flag question

Question text

The methods of membrane transport that don't require protein channels or carriers are

Select one:

a. osmosis

b. diffusion

c. phagocytosis

d. exocytosis

e. all of the above

Question 7

Not yet answered

Marked out of 1.00

Flag question

Question text

Complete the following sentences: "Primary active transport is dependent on __________. Secondary active transport is dependent on __________ created by __________.

Select one:

a. channel proteins, electrochemical gradient, carrier proteins

b. electrochemical gradient, ATP, mitochondria

c. electrochemical gradient, ATP, primary active transport

d. ATP, electrochemical gradient, primary active transport

e. carrier proteins, electrochemical gradient, channel protein

Question 8

Not yet answered

Marked out of 1.00

Flag question

Question text

Which of the following is a reduced compound?

Select one:

a. CO2

b. O2

c. N2

d. NAD +

e. NADH

Question 9

Not yet answered

Marked out of 1.00

Flag question

Question text

Gel electrophoresis separates DNA fragments according to their:

Select one:

a. base sequence

b. size

c. percentage of labelled nucleotides

d. electrical charge

Question 10

Not yet answered

Marked out of 1.00

Flag question

Question text

G0 is:

Select one:

a. part of interphase

b. the phase of the cell cycle where DNA replication occurs

c. the phase of the cell cycle where two identical daughter cells are created

d. a special "resting" phase in which cells are in a non cycling state

e. a special phase where the number of chromosomes in a parent cell is reduced by half such that each daughter cell contains only one member of a pair of homologous chromosomes

Question 11

Not yet answered

Marked out of 1.00

Flag question

Question text

At which pH will the concentration of hydrogen ions be equal to the concentration of hydroxide ions?

Select one:

a. pH 1

b. pH 5

c. pH 7

d. pH 9

e. pH 14

Question 12

Not yet answered

Marked out of 1.00

Flag question

Question text

Which of the following enzymes has proofreading activity?

Select one:

a. Ligase

b. Helicase

c. Topoisomerase

d. DNA polymerase

e. Peptidyl transferase

Question 13

Not yet answered

Marked out of 1.00

Flag question

Question text

The process of _______________ cuts introns from the primary transcript and the final "processed" mRNA is produced.

Select one:

a. RNA cleaving

b. RNA translocation

c. RNA elongation

d. RNA splicing

Question 14

Not yet answered

Marked out of 1.00

Flag question

Question text

Transcription is initiated when RNA polymerase binds to

Select one:

a. a promoter

b. an initiator

c. a transciptor

d. a codon

Question 15

Not yet answered

Marked out of 1.00

Flag question

Question text

Complete the following sentences: "__________ connect the extracellular matrix with microfilaments. __________ connect intermediate filaments from adjacent cells."

Select one:

a. Cadherins, Integrins

b. Connexins, Cadherins

c. Integrins, Cadherins

d. Integrins, Connexins

e. Connexins, Integrins

Question 16

Not yet answered

Marked out of 1.00

Flag question

Question text

Which of the following regions of RNAs are translated?

Select one:

a. 5' UTR

b. exons

c. introns

d. 3' UTR

e. poly-A

Question 17

Not yet answered

Marked out of 1.00

Flag question

Question text

Control of gene expression in eukaryotic cells occurs at which level(s)?

Select one:

a. only the transcriptional level

b. epigenetic and transcriptional levels

c. epigenetic, transcriptional, and translational levels

d. epigenetic, transcriptional, posttranscriptional, translational, and posttranslational levels

Question 18

Not yet answered

Marked out of 1.00

Flag question

Question text

Cellular organelles containing hydrolytic enzymes are called:

Select one:

a. peroxisomes

b. lysosomes

c. ribosomes

d. mesosomes

Question 19

Not yet answered

Marked out of 1.00

Flag question

Question text

______ are chemicals or combinations of chemicals that take up excess hydrogen ions or hydroxide ions in order to keep the pH constant.

Select one:

a. acids

b. bases

c. salts

d. buffers

e. carbohydrates

Question 20

Not yet answered

Marked out of 1.00

Flag question

Question text

Which of the following proteins appear in some stages of the cell cycle and are degraded at other stages?

Select one:

a. kinases

b. cyclins

c. nucleotides

d. phosphatases

e. none of the above

Question 21

Not yet answered

Marked out of 1.00

Flag question

Question text

Which of the following correctly matches an organelle with its function?

Select one:

a. mitochondrion photosynthesis

b. nucleus cellular respiration

c. ribosome manufacture of lipids

d. lysosome movement

e. central vacuole storage

Question 22

Not yet answered

Marked out of 1.00

Flag question

Question text

What is the sequence corresponding to the following electropherogram obtained by Sanger sequencing (green: A; red:T; black: G; blue: C)?

Select one:

a. CCGTTATGAAC

b. GGCTTATGAAG

c. CAACTATTGCC

d. GGCAATAGTTG

e. CCGTTATCAAC

Question 23

Not yet answered

Marked out of 1.00

Flag question

Question text

Which of the following statement is true

Select one:

a. the two DNA strands are parallel and complementary

b. the two DNA strands are anti parallel and non-complementary

c. the two DNA strands are anti-parallel and complementary

d. none of these

Question 24

Not yet answered

Marked out of 1.00

Flag question

Question text

The energy-requiring process by which small molecules are joined to form larger molecules is specifically called

Select one:

a. metabolism

b. anabolism

c. catabolism

d. enzymatic reactions

Question 25

Not yet answered

Marked out of 1.00

Flag question

Question text

When DNA replication starts

Select one:

a. the phosphodiester bonds between the adjacent nucleotides break

b. the bonds between the nitrogen base and deoxyribose sugar break

c. the leading strand produces Okazaki fragments

d. the hydrogen bonds between the nucleotides of two strand break

Question 26

Not yet answered

Marked out of 1.00

Flag question

Question text

A(n)_______ is the movement of a segment of a chromosome from one chromosome to another nonhomologous chromosome

Select one:

a. inversion

b. translocation

c. deletion

d. duplication

Question 27

Not yet answered

Marked out of 1.00

Flag question

Question text

Complete the following sentences: "Replication forks from the same origin of replication extend __________. __________ DNA strand is used as template for the leading strand at one fork and for the lagging strand at the second fork. New DNA is synthesized from 5' to 3' on the __________."

Select one:

a. unidirectionally, A different, both the leading and lagging strands

b. bidirectionally, The same, leading strand

c. bidirectionally, The same, lagging strand

d. unidirectionally, A different, leading strand

e. bidirectionally, The same, both the leading and lagging strands

Question 28

Not yet answered

Marked out of 1.00

Flag question

Question text

Manufacturing recombinant DNA molecules involves cutting a gene from its normal location, inserting it into a circular piece of DNA from a bacterial cell, and then transferring the circle of DNA to cells of another species. Which of the below describe the circular piece of DNA?

Select one:

a. restriction enzyme

b. plasmid

c. bacteriophage

d. transposon

Question 29

Not yet answered

Marked out of 1.00

Flag question

Question text

Complete the following chemical equation to make it balanced: glycerol + ___ ? triacylglycerol + ___

Select one:

a. 3 fatty acid, 3 H2O

b. fatty acid, H2O

c. 3 OH-, 3 H+

d. 3 H2O, 3 fatty acid

e. fatty acid, 3 H2O

Question 30

Not yet answered

Marked out of 1.00

Flag question

Question text

Which structure is found in plant cells but not animal cells? Check all that apply.

Select one or more:

a. Cell wall

b. Chloroplast

c. Plastid

d. Central vacuole

e. Lysosomes

Weekly leaderboard

Home
Homework Help 3,900,000
Biology 460,000
Start filling in the gaps now
Log in