cell division: mitosis
TRANSCRIPT
BIO 221
Nouf AlSubhiKing Abdulaziz University
Lecture 2
Introduction
All Cells Have Three Basic Features: Cell Membrane, Genetic Material, Cytoplasm
Types of cells
1-Prokaryotic 2-Eukaryotic
.
Introduction
Transverse section of bacteria and animal cell
Transverse sections of animal and plant cell
Introduction
Nucleus structure:
A Nucleus is made up of 5 parts
1- Nuclear Envelope
2- Nuclear Pores
3- Nuclear sap
4-Chromatin / Chromosomes
5- Nucleolus
Central dogma of genetics
DNA Transcription RNA Translation Protein
A- Chromosome Morphology:
1 -Two arms separated by
centromere
2 -Two sister chromatids
contains tightly coiled DNA
Chromosomes
Chromosomes
Identify the numbered part on chromosome?
B- Chromosome Number :1-Diploid chromosome number: is the
number of chromosome in somatic cell (2N) in human = 23pairs
2-Haploid chromosome number: is the number of chromosome in gametes (from eggs, sperm ) cell (1N) in human = 23single
Chromosomes
Eukaryotic Cell Cycle
• The eukaryotic cell cycle consists of two basic stages: Interphase and mitosis.
Interphase:is the phase of the cell cycle in which the cell spends the majority of its timePreparing for cell division
Interphase =20 h Mitosis =1 h
• Mitosis for proliferation of somatic cell.
• Mitosis results in:
division in the nucleus to produce two nuclei has the same type and numbers of chromosomes .
• Mitosis is divided into four stages: prophase, metaphase, anaphase, and telophase.
Cell division: Mitosis
Nuclear envelope disappears
Chromosome along the equator of the cell
formation of cell plate
formation of two Nucleoli as same number and type of
chromosome
Nucleoli and
Cytokinesis and cleavage
• Cytokinesis follows mitosis, and it is the last stage of the cell cycle.
• Cytokinesis divides the entire cell into two new cells.
• Cytokinesis plant cell• Cleavage + Cytokinesis
animal cell
Steps of root tip squash method
1-Growing onions and wait it for root growth and then treated it by 2ml Carnoy fixative or alchohol 70% for 24 h.
2- Using scissors , cut 2 roots tips about 1cm long and transfer them into a test tube
3- Fill the tube about 2-3ml with 1N HCL and cover the tube by gauze then tie it with rubber
4- Place the tube in 60 °C water bath and incubate for 5 min.
5- Remove the tube from water bath
Steps of root tip squash method
6- remove the HCL from the test tube and rinse the roots in the water about 3 times
7- cover the root with the aceto carmine stain and incubate the root in the stain for 12 min.
8- Transfer a root to the slide
9- using a razor blade cut off most of the unstained part of the root and discard it
10-Cover the root tip by a cover slip then press down formally with one finger for flattening the sample
Steps of root tip squash method
11- put one more drop of stain and leave it for 1min then rinse it and cover the root tip by a cover slip
12-Examine under the microscope at low power and high power
الحازمي : - إيمان أ إعداد
Steps of root tip squash method
Mitosis in Onion Root Tips
Cell division: Mitosis
Cell division: Mitosis
Cell division: Mitosis
Cell division: Mitosis