Question

1. All of the following are true of receptor kinases except:

	a.	Are found on the plasma membrane.
	b.	Are ion channels.
	c.	Dimerize when binding to their signaling molecule.
	d.	Are transmembrane proteins.
	e.	Contain a protein kinase domain.

2. During protein synthesis, a protein is made in which direction?

	a.	From the 2' end to the 3' end.
	b.	From the 3' end to the 2' end.
	c.	From the 2' end to the 3' end and from the 3' end to the 5' end.
	d.	From the amino-terminal end to the carboxyl-terminal end.
	e.	From the carboxyl-terminal end to the amino-terminal end

3. What type of molecule is ATCAGCTAG?

		Protein.
		Phospholipid.
		DNA.
		RNA.
		Glucose.

4. In the lytic cycle:

	a.	A bacteriophage interacts with an episome and stimulates transcription of the bacterial chromosome.
	b.	A bacteriophage replicates to very high numbers within a bacterial cell and eventually the bacterial cell bursts to release the new viruses.
	c.	A bacteriophage binds to the lac repressor and stimulates translation of Rubisco RNA.
	d.	A bacteriophage genome is stably integrated into the bacterial chromosome.
	e.	A bacteriophage stimulates the transcription of an R factor.

5. Which of the following organisms would be expected to have the largest genome size?

	a.	Bacteriophage T4.
	b.	Escherichia coli.
	c.	Yeast (Saccharomyces cerevisiae).
	d.	Homo sapiens (humans).
	e.	Human immunodeficiency virus (HIV).

6. For a protein to be inserted into the endoplasmic reticulum membrane:

	a.	The protein must have a promoter.
	b.	The protein must have a telomere.
	c.	The protein must have a centromere.
	d.	The protein must have a signal sequence.
	e.	The protein must be in a complex with DNA.

Answer 1

1.

Receptor Kinase

Receptor kinases are receptors present on the cell surface for many polypepetide growth factors, hormones.. They are found on the surface of plasma memebrane. They are ion channels. When these receptor kinase bind to signal molecules the receptors dimerize. They lso contain a protein kinase domain.

But receptor kinases are not transmembrane proteins. They are single pass membrane proteins.

Option d is the answer.

2.

Polypepetide chains or proteins are synthesised from amino to carboxy terminus. ( N terminus to C terminus ) during the process of translation.

So protein is made in the direction from amino terminal end to the carboxyl terminal end.

Other options are wrong. It is not synthesised as DNA or RNA .

Option d is the answer.

FROM THE AMINO- TERMINAL END TO THE CARBOXYL - TERMINAL END.

3.

ATCAGCTAG

These are bases or nucleotides. Nucleotides are the building blocks of DNA and RNA. So this is not phospholipid, protein or glucose. There is presence of Thymine/T instead of Uracil /U , which shows that the molecule is DNA. In RNA Thymine is absent and have uracil instead.

So this molecule is DNA

Option c is the answer.

DNA

4.

Lytic Cycle

Lytic Cycle is the process of viral/ bacteriophage reproduction inside cells. It involves 5 steps - Attachment, Penetration, Transription, Biosynthesis, Maturation. Firstly the bacteriophage attaches to the surface of host cell and inject its genetic material to cell( penetration ). Host cell DNA is degraded and phage DNA replicates inside cell. Then it matures and later released from cell.

So in the lytic cycle, a bacteriophage replicates to very high numbers within a bacterial cell and eventually the bacterial cell bursts to release new viruses.

Other options are wrong. Bacteriophage is not involved in transription of of bacterial chromosome or translation of Rubisco RNA. The bacteriophage genome is not stably integrated into bacterial chromosome. The bacteriophage doesnot stimulate transription of R factor.

Option b is the answer.

5.

Genome size is the total number of DNA basepairs in one copy of haploid genome.

* T4 bacteriophage

have 168,903 basepairs, 200 nm long

* E.Coli

4600000 basepairs

* Yeast- saccharomyces cerevisiae

12 mb genome size

* Hamo sapiens

3 Bilion basepairs

* HIV

9.2 kb

  

So from the data it is seen that human/ Homo sapiens have high genome size.

Option d is the answer.

HOMO SAPIENS (HUMANS )

6.

For a protein to be inserted into the endoplasmic reticulum membrane require specific topogenic sequences. These sequences of 25 aminoacids ensure that a protein acquires proper orientation during its insertion into the endoplasmic reticulum membrane.

Other options are wrong. The insertion doesnot require promoter, telomere, centromere.

Option d is the answer.

THE PROTEIN MUST HAVE A SIGNAL SEQUENCE.