BIO301 Midterm Past Papers Updated

BIO- 301 · CURRENT MID TERM FILE · LION GROUP OF ZOOLOGIST · Non disjunction · one · gamete · receives · two · copies · of

homologous chromosomes and other will have no copy.

2Cluster rule

Stated that pyrimidines often occur in clusters, and hence on the complementary strand purines do likewise

4. Chromosome structure:

chromosomes are made of DNA And associated proteins. Chromosome carries part or all of a cell’s genetic information. Chromosomes

have

sister

chromatids.

Centromere

is constricted

region,

where · chromatids · are

attached.

A

chromosome constitutes DNA molecule, a protein Histones and supercoiled DNA.

5.Polyploidy: · Multiples of haploid number · • Triploidy or tetraploidy etc · • Fetus does not survive · Two major types · Autopolyploidy · Allopolyploidy · 6.Acquired Variation

Acquired variation result from an individual’s activities or nutrition

or · from · environment · conditions · during · a lifetime. Acquired · characteristics · can · not · be

inherited. Language, obesity, athletic skills etc Example: Apples - different position on same tree.

Variation by genetic and environment

Many variations - both genetic and environmental. Height depend on what genes you inherit and the amount of food you get. There are six common types of epistasis gene interactions: dominant, dominant inhibitory, duplicate dominant, duplicate recessive, polymeric gene interaction, and recessive.

Q7. What is Inherited Variations?

Inherited variations result from the activity of genes. Genetically controlled and cannot be altered. Blood groups, finger prints and sex etc.

8.Genetic mapping

9.Size at stages of mitosis:

There is variation in the sizes of chromosomes during different stages of mitosis such as

Interphase: Chromosomes are longest & thinnest. Prophase: there is a progressive decrease in their length accompanied with an increase in thickness. Anaphase: chromosomes are smallest.

Metaphase: chromosomes can be easily observed. Chromosomes are studied during metaphase

Measurement of chromosomes: Chromosomes are generally measured during mitotic metaphase.