Thursday, August 30, 2007

Lectures On Genes -part 1

What is a gene?

The genes are hereditary units that control our characters .Characters include everything ,right from our eye colour,hair colour,skin our behaviour,our looks,our sound,the way we look,physical characters such as tallness,shortness.......etc.This is passed on from one one generation to another.
So what do we call this "characters "that pass from our parents to us .They are called as "Traits".

How we can we define genes?(2-Mark )

Genes are the hereditary units which control the characters of living beings.A gene brings about its action by specifying the amino acid sequences of proteins.
(Proteins form the major component of the functioning of a cell. Like other biological macromolecules such as polysaccharides and nucleic acids; proteins are essential parts of organisms and participate in every process within cells. Many proteins are enzymes that catalyze biochemical reactions, and are vital to metabolism.Proteins also have structural or mechanical functions, such as actin and myosin in muscle, and the proteins in the cytoskelton, which forms a system of scaffolding that maintains cell shape. Other proteins are important incell signalling, immune responses ,cell adhesion and the cell cycle. Protein is also a necessary part of our diet, since animals cannot synthesise all the amino acids and must obtain essential aminoacids from food. Through the process of digestion, animals break down ingested protein into free amino acids that can be used for protein synthesis).
So a gene can also said to contain the directions for building all the proteins present in a cell.
Genes are present in long thread like structures called "Chromosomes" that are present inside the nucleus of a cell.Both the genes and chromosomes are made up of DNA .
A single chromosome can contain many genes .

Wednesday, June 6, 2007

30.Proteoglycans are made of proteins and
a.Glucose amine
b.sialic acid

ans. d.mucopolysaccharides.
29.The highest level of packing of DNA with hisyones is observed during

a. prophase
b. metaphase.
c. anaphase
d. G1 phase

c. Metaphase

28.The centtromeres usually cocnsists of
a.Tandem repeats
b. highly repeated satelite DNA
c. long stretches of DNA
D. redundant regions

ans. b. highy repeated satellite DNA

27.Cyclic photophoshorylation is carried out by
a.P.S 1
B. P.S 2
c. Botha&b 2 alone
Ans. a. P.S 1
26.Number of chromosomes in Drosophila is
a. 6
b. 12
c. 8
25. Homologous chrormosomes similar in both sexes are called
a. Heterosomes
b. androsomes.
d. None of the above
Ans.c. Autosomes
24.The principle of linkage was discovered by

a. Mendel
b. sutton
c. Morgan
d. Bateson and Punnet

Ans. d. Bateson &Punnet
23.The term Mutation was introduced by

a. Mendel
b. Lamarck
c. Hugo de vries
d. Darwin

Ans. c.Hugo de vries

Thursday, May 24, 2007

4. A collection of cleaved fragnebts that represent the entire genome

a. Sines


c. Library


Ans. d.cDNA

5. Amethod for transferring RNA from an agarose gel to a nitrocellulose paper on which RNA can be detected by a suitable probe.

a. Southern Blot

b.Northern blot

c.Eastern blot

d.Western blot

Ans : b.Northern blot

6. DNA is single stranded in

a. Prokaryotes

b. Eukaryotes

c. *x 174

Ans. c.*x174

7. Frame shift mutations include which of the following

1. Deletion



4. Insertion

a. 1 only


c. 2&4

d.1 &4

Ans. d. 1&4

Tuesday, May 15, 2007

Questions from life sciences-Part 1

1.Cell Organelle having electron transport system is:

2.An average eukaryotic cell is larger to prokaryotic cell

a. 100 times
b.50 times
c.10 times
d.5 times

3.The E.R occurs in the form of

d.All of the above