Exam 3 Flashcards
Chromatin
Less coiled DNA, accessible to enzymes and considered to be in an active state
Homologous chromosome
A chromosome which has undergone replication in the S phase of interphase, before mitosis or meiosis begins and looks like an X
Sister chromatid
Each half of a replicated chromosome
Interphase
The stage of the cell cycle where the cell spends most of it’s time, and undergoes normal life and produces organelles
Mitosis
One 2n cell produces 2 - 2n daughter cells.
All living things can undergo mitosis.
Only egg and sperm cells do not undergo mitosis.
There is one cell division event in mitosis.
Prophase
Chromosomes begin to condense and the nuclear envelope dissolves
Metaphase
Chromosomes attach to the spindle fibers and align at the equator or metaphase plate of the cell
Anaphase
Sister chromatids seperates and begin to move to opposite poles of the cell
Telophase
Chromatids are at the poles of the cell, a nuclear envelope reforms around the Chromosomes, and the cytoplasm is about to divide in cytokinesis
Chromosome
Highly coiled DNA seen only during cell division
Somatic cells
Normal body cells with a diploid or 2n chromosome number
Gametes
Egg or sperm with a haploid or 1n chromosome number
Meiosis
Cuts the chromosome number in half.
For example, if a stem cell has 20 chromosomes at the beginning of meiosis 1, the resulting 4 daughter cells will each have 10 chromosomes.
Genetic variability
Is increased by crossing over, sexual reproduction with two different parents, independent assortment, and occasional mutation.
Reduces genetic variability
Cloning or parthenogenesis (one parent with both sex organs producing offspring, I.e. Lizards, some snakes)
Cleavage
The fertilized egg cell or zygote begins to divide
Grastriculation
3 germ layers form.
Ectoderm, endoderm, mesoderm
Neurulation
The neural tube forms which will become the spinal cord. The notochord forms and becomes the spinal cord.
Organogenesis
The organs undergo formation and differentiation when they become functional.
Acrosomal enzymes
And actin fibers in the head of the sperm aid penetration of the sperm into the egg cell of ovum during fertilization.
Cowper’s gland or bulbourethral gland
Produces a mucus like lubricating substance in the male
Bartholin’s gland
A gland in the female which produces a mucus like lubricating substance
Prostate gland
Produces a milky white, alkaline (pH basic) fluid which increases the pH of the vagina and helps improve the chance of sperm living
Scrotum
Tissue sac which houses the testes
Epididymis
Highly coiled tube which stores the developing sperm
Seminiferous tubules
Tubule with sperm cells in the wall. Site of actual sperm production.
Vas deferens
The tube which transports sperm and seminal fluid from the region of the testes to the beginning of the urethra.
Penis
Male organ used for sperm transfer and urination
Uterus
A thick-walled, narrow organ which nourishes the embryo during development
Endometrium
The lining of e uterus
Cervix
Muscular base of the uterus. Produces secretions and closes the uterus.
Graffian follicle
One follicle per ovary which will produce a ripe egg cell or ovum