Tag: enzymes classification and cofactors

Quizzes (0) Questions (103)

Questions Related to enzymes classification and cofactors

Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

Name the hormone that stimulate the secretion of gastric juice.

  1. Renin

  2. Enterokinase

  3. Enterogastrone

  4. Gastrin
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Gastrin is a peptide hormone, which is secreted by the gastric glands in the stomach wall. The gastrin stimulates secretion of gastric juice rich in pepsin and hydrochloric acid. The stimulation for secretion of gastrin is presence of peptides derived from dietary proteins.

Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

Proteinaceous nature of enzyme was suggested by

  1. T. Cech

  2. Kuhne

  3. E. Buchner

  4. Northrop
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Enzymes are biological catalysts. The multitude of biochemical reactions that make cellular metabolism possible are due to enzymes. The isolation and crystallization of urease by James Sumner in 1926 provided a breakthrough in early enzyme studies. Sumner found that urease crystals consisted entirely of protein, and he postulated that all enzymes are proteins. In the absence of other examples, this idea remained controversial for some time. Only in the1930s, was Sumners conclusion widely accepted, after John Northrop and Moses Kunitz crystallized pepsin, trypsin, and other digestive enzymes and found them also to be proteins.

Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

Enzyme amylase belongs to category 

  1. Oxidoreductases

  2. Transferases

  3. Hydrolases

  4. Isomerases
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

An amylase is an enzyme that catalyses the hydrolysis of starch into sugars. A hydrolase or hydrolytic enzyme is an enzyme that catalyzes the hydrolysis of a chemical bond. So, the correct answer is option C.

Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

The enzyme which combines with a nonprotein prosthetic group to form a functional enzyme is called

  1. Apoenzyme

  2. Holoenzyme

  3. Coenzyme

  4. Proenzyme.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The non-protein component or prosthetic group along with the protein component or apoenzyme is called the holoenzyme. The prosthetic group may be metal ion or a co-enzyme that may be firmly or losely bound to the enzyme.
So, the correct answer is option B.

Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

Enzymes generally have

  1. Same pH and temperature optima

  2. Same pH but different temperature optima

  3. Different pH but same temperature optima

  4. Different pH and different temperature optima
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Enzymes are biocatalyst that affects the rate of biochemical reactions they generally have the same pH and temperature Optima at which they work efficiently. 

So, the correct option is 'Same pH and temperature optima'. 

Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

Class of enzymes contained in lysosomes is 

  1. Lyases

  2. Ligases

  3. Hydrolases

  4. Transferases
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A lysosome is a membrane-bound organelle found in nearly all animal cells. They are spherical vesicles which contain hydrolytic enzymes that can break down many kinds of biomolecules. So, the correct answer is option C.

Multiple choice enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

Which is not a hydrolase?

  1. Protease

  2. Dehydrogenase

  3. Sucrase

  4. Amylase

  5. Esterase
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation


A dehydrogenase is an enzyme that oxidizes a substrate by reducing an electron acceptor, usually a flavin coenzyme known as FMN.
While all other are hydrolases because they take part in the hydrolysis. 
So the correct answer is C.

Multiple choice enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

Ribozyme is

  1. RNA with additional phosphate.

  2. RNA without sugar.

  3. RNA without uracil.

  4. RNA acting as enzyme.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Most of the enzymes are large protein molecules except for a small category of catalytic RNA molecules. The catalytic RNA molecules are called Ribozymes. Ribozymes play an important role in intron splicing and other reactions during processing of RNA. The ribozymes are an important example of self catalytic (RNA) molecules, i.e., one type of RNA (ribozyme) acting on another type of RNA (like mRNA). Some of the introns are self splicing which catalyze their own splicing.

Multiple choice enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

Digestive enzymes are found in

  1. Lysosomes

  2. Mitochondria

  3. Chloroplast

  4. All of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Lysosomes are membrane-bound vesicles that contain digestive enzymes, such as glycosidases, proteases and sulfatases. Lysosomal enzymes are synthesized in the endoplasmic reticulum (ER), are transported to the Golgi apparatus, and are tagged for lysosomes by the addition of mannose-6-phosphate label. Digestive enzymes are not found in chloroplast and mitochondria. 

Therefore, the correct answer is option A.

Multiple choice enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

Enzymes that catalyse inter-conversion of optical, geometrical or positional isomers are

  1. Ligases

  2. Lyases

  3. Hydrolases

  4. Isomerases
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Ligases are the enzymes which catalyze joining together of two DNA segments. Lyases catalyze the breaking of chemical bonds without hydrolysis while hydrolases catalyze hydrolytic cleavage of bonds. Isomerases catalyze interconversion of optical, geometrical or positional isomers of a particular enzyme.