(1)

(2)

(3)

(4)

(1)

(2)

(3)

(4)

(5)

(6)

(7)

CHALAZA END

EMBRYO SAC

INTEGUMENT

MICROPYLE

RAPHE

NUCELLUS

HILUM

FUNICLE

L.S. OF ANATROPOUS OVULE

Phases of Spermatogenesis Type of

division

Type of

germ cells

46

4646

4646

46

23

23 23 23 23

23 23 23 23

23

46 46

Sp

erm

ato

go

nia

Primary spermatocyte

Secondary spermatocyte

Spermatids

Spermatozoa

or

Sperms

Meiosis-I

MaturationMeiosis-II

Fig. Stages in Spermatogenesis

Multiplication

Mitosis

Growth

(8)

Repressor

Operator

switched on

Inducer

Lactose

X

Transcription

Transcription

PermeaseTransacetylaseB-galactosidase

Lactose Metabolism

m-RNA

(9)

RG PG OG Lac Z Lac Y Lac A

Repressor

Operator

Switched off

Parents-

(10)

Operon Model in the presence of Lactose

No Transcription

No Translation

RY Ry rY ry

RRYYRY RRYy RrYY RrYy

RRYyRy Rryy RrYy Rryy

RrYYrY RrYy rrYY rrYy

RrYyry Rryy rrYy rryy

F generation2

(11)

VIRULENTS-Strain

Died

Died

SURVIVED

VIRULENTS-Strain

VirulentS-Strain

Non-VirulentR-Strain. If

Present

Absense ofbacteria

SURVIVED

NON-VIRULENTR-Strain Heat killed

virulentS.Strain Heat killed

Virulent S-Strain+Non virulent

R.Strain

(12)

b a

Mosses

Algae Lichens

Ferns

(13)

DenaturationHeat

5’

5’3’

3’ds DNA

Annealing

DNA polymerase(Tag polymerase)+ de oxynucleotides.

Primers

5’ 3’

Extension

5’

5’

3’

3’

5’

5’3’

30 cycles

3’

Primers

5’

5’3’

3’

1-billion times

(14)

(15)