Kategóriák: Minden - genetics - meiosis - rna - chromosomes

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Cell division & Mendelian Genetics & Genetic Inheritance &Molecular genetics

Cell division and genetic inheritance are fundamental concepts in biology. Eukaryotic cells undergo mitotic and meiotic divisions, with mitosis focusing on growth and repair, and meiosis on producing reproductive cells.

Cell division
& Mendelian Genetics & Genetic
Inheritance &Molecular genetics

Cell division & Mendelian Genetics & Genetic Inheritance &Molecular genetics

DNA

DeoxyriboNucleic Acid
• Right-handed fashion
Antiparallel strands
double helix
Chargaff’s rules
A=T, C=G
The base composition of DNA varies between species
dictates life in two manners
controls the production of proteins
transfers hereditary information from generation to generation
the complex chemical

Genetics

Sex Chromosomes
Haplo-diploid system
Z-W system
X-O system
X-Y system
Linked Genes
Pedigree Analysis
Family tree

Inheritance patterns

interrelationships of parents and children across generations

Non-mendelian inheritance
Codominance
Incomplete dominance
Probability and Genetics
Rule of addition

Chance that an event can occur 2 or more different ways

– probability of Bb x Bb -> Bb

– sum of the separate probabilities

Rule of multiplication

Chance that 2 or more independent events will occur together

– probability of Pp x Pp -> pp

Mendel’s Law of Segregation
Different pairs of alleles assort independently
Two alleles of the same gene segregate equally
test-cross
breeding the mystery individual with a homozygous recessive individual
Dominant phenotype couldbe either homozygous dominant or heterozygous
To test the equal gamete formation in F1
Gregor Johann Mendel
Mendel’s Principles

Members of one gene pair segregate independently from other gene pairs during gamete formation

genes become separated in gamete formation

Experimented with pea plantsfor 8 year

The ratio of two classes of progeny was 3 : 1

In F 2, the missing trait reappears in ¼ of the progeny

F 1 progeny resembles one of the parents

RNA

There are three kinds of RNA
Ribosomal RNA
Transfer RNA (tRNA)
Messenger RNA (mRNA)
Ribose
Uracil
Ribonucleotides

Chromosomes

Bacterial Chromosome
Plasmids help bacteria to survive stress
pick up new plasmids or lose them
smaller circular DNA molecules
not bound with proteins
located in the cytoplasm
single circular chromosome
Double-stranded DNA
Human
46 per cell
23 pairs of chromosomes

Cell division

Eukaryotes
Meiotic cell division

Stage of Meiosis

telophase II,

the chromosomes arrive at opposite poles

Subtopic

anaphase II

the sister chromatids separate.

metaphase II

the sister chromatids are arranged at the metaphase plate

Meiosis II

is very similar to mitosis

telophase I

anaphase I

One chromosome of each pair moves toward opposite poles, guided by the spindle apparatus.

metaphase I

pairs of homologs line up at the metaphase plate, with one chromosome facing each pole.

prophase I

chromosome pairs with its homolog (synapsis) and crossing over occurs

Objectives

To produce reproductive cells

. Sexual life cycle

Mitotic cell division

Cells that can undergo mitotic cell division include

Shoot and root apical meristems of plant tissue

Epithelial cells, Bone marrow of animal tissues

Mitosis and cytokinesis

Cytokinesis occurs during telophase

In plant cells, a cell plate forms during cytokinesis

In animal cells, cytokinesis occurs by a process known as cleavage, forming a cleavage furrow

Mitosis

Telophase

Anaphase

Metaphase

Prometaphase

Prophase

Interphase

Chromosomes are duplicated only during the S phase.

The cell grows during all three phases

- Can be divided into 3 phases

G2 phase

S phase

G1 phase

~90% of the cell cycle

Prokaryotes
Binary fission
Chromosome
Eukaryotic cell

consist of chromatin

Linear chromosome

Prokaryotic cell

Not associated with proteins

Circular chromosome