3.9b - Female Reproductive System

before a pregnancy occurs the uterus structure is no larger then an orange.

Ovary - meiosis occurs and production of female gamete(eggs) 

Oviducts - carry the eggs to the uterus and where fertilization takes place. where sperm cells meet the egg cells. 

Uterus - wall of the uterus is made of muscle. stretches to accommodate pregnancy and contracts during birth. 

Lining of the uterus - develops the fertilized egg into the embryo and then the child. can see the development here of the placenta 

Cervix - entrance to the uterus - where sperm cells enter. 

Uterus space - where the sperm and egg cells move. Embryo develops into the unborn child

Vagina - collects the sperm cells and allows them to pass throw the cervix into the uterus 

3.9a - Male Reproductive System

Bladder - Store urine 

Testis - 2 of them - carry out meiosis - produces the gamete, sperm 

epididymis - stored sperm cells 

vas deferens - carry sperm cells to the penis during sexual stimulation. the tube pulses making the walls contract and push the sperm from the testis to the penis

prostate - adds about 20/30% of the volume of the semen. contains sugars and is alkali. 

Seminal Vesicles - 70& of the volume of the semen. contains sugars and is alkali 

When sperm cells are combined with the prostate and seminal vesicles secretions we have semen. - carried forward and down to the urethra 

Urethra - common tube that joins the left and right testis. takes semen/urine down the penis

Penis - carries sperm cells into the vagina during sexual intercourse 

3.24 c - Mitosis

background information:

INTERPHASE

in a microscope nucleus would be seen as a spherical structure, would be unable to see chromosomes -- this is the interphase. this is when DNA replication occurs. 

PROPHASE

nucleus membrane breaks down - prophase 

chromosomes become visible - visible as a pair of "chromatids"  (two copies) 

LATE PHROPHASE

cell division proceeds - network of protein molecules (spindle and spindle fibres)

late phrophase - chrmosome pair will move towards spindle and join onto one fibre

METAPHASE

pair of chromatids are attached to spindle fibre by centromere. 

characteristic - chromosomes are arranged across the middle. the 'equator' of the cell. 

ANAPHASE 

spindle fibre shortens pulling chromatids in different directions 

pair of chromatids move apart to the poles of the cell 

separation of the pair of chromatids 

TELOPHASE

end of mitosis 

nucleus begins to reform around the chromosomes at either end of the cell

new nucleus of two new cells 

formation of two nucli at opposite ends of the cell 

CYTOKINESIS

cell splits into two - not part of mitosis! 

cell begins to move inwards to divide cytoplasm in half. - membrane fuses across equator to produce two cells 

they each contain a chromosome that is the same as the parental cell 

P - aPpear

M - Middle

A - Apart

T - Two

Cytokinesis is NOT part of Mitosis 

3.24 b - Mitosis

detail of mitosis: 

first cell has to copy its chromosomes in order for the two split cells to have he same number of chromosomes and same sets 

-  this is DNA replication (copy chromosomes) 

- DNA replication - each chromosomes undergoes copying process. held together by centromere. 

- they are now a 'pair of chromatids' 

- takes place in the nucleus while it is still intact - interphase of the cell cycle 

3.24 a - Mitosis

mitosis - cell division --> growth/increase in number of cells

Outline of process:

- begin with cell - with nucleus. 

- number of chromosomes in the nucleus - diploid number (2n) 

- for humans 2n = 46

- for cats 2n = 38

- mitosis - cell divides into two cells, each with nucleus, each cell has a diploid nucleus - these cells are identical/daughter cells

- identical because 1. Same number of chromosomes. 2. same set of chromosomes 

How are the copies of chromosomes made? and how are they separated? 

3.16 - DNA and Genetic information

first Chromosome - 1000's of genes. 

- gene loci --> double helix - parallel

- double helix --> 'sugar - phospate backbone'

- in the center, group of molecules called bases 

- Adenine, thymine, cytosine and guanine 

- in the molecule they are holding together the two helisis 

- pairing between A-T and G-C - base pairs (ALWAYS in DNA) 

- order of the bases on right side A, C, T, G, A, A, C, C, A, G --> this is the gene 

- Gene in the nucleus - order of the bases (ATGC) 

                                       - number of the bases 

this constructs a protein in the cytoplasm - gives characteristic 

Question: Why are the base pairs always arranged as  A-T and G-C? 

3.15 - Genes

Photo is a molecule of DNA - Double helix shape 

One section is a Gene 

- This gene carries the information of the characteristic of the organsim 

could be: a blood group or a petal colour on a flower 

- Genes are located in the nucleus 

- information passed to cytoplasm 

- then transformed into protein 

- this protein controls the characteristic 

information flows from gene (nucleus) to protein (cytoplasm) 

Question: Are the number of genes affected by your gender?