BIO EXAM REVIEW Flashcards
Diploid
two complete sets of chromosomes, one from each parent.
what cells are diploid in the body?
Muscle cells
Skin cells
Blood cells
Nerve cells
Bone cells
Haploid
a cell that contains a single set of chromosomes
what cells are haploid in the body?
only egg and sperm cells
how many chromosomes do humans have?
46
Gamete
reproductive cell of a plant or animal
how many chromosomes do gametes have?
23
why do gametes have only 23 chromosomes?
gametes are produced during meiosis, which is a type of cell division that reduces the number of chromosomes in a parent diploid cell by half.
what is fertilization?
the fusion of a haploid male and female gamete to create a diploid cell (zygote)
Somatic cells
any cell in a living organism besides reproductive cells
germ line cell
the cells that form eggs in women and sperm in males
what is mitosis used for?
during mitosis one cell divides to create 2 identical cells, this is for growth and to replace damaged or worn out cells
Stages of mitosis
prophase
metaphase
anaphase
telophase
cytokinesis
what happens in prophase?
condensation of chromosomes
movement of the centrosomes
formation of the mitotic spindle
beginning of nucleoli break down
what happens in metaphase?
mitotic spindle is fully developed
centrosomes are at opposite poles of the cell chromosomes are lined up at the metaphase plate
what happens in anaphase?
sister chromatids will separate and move to opposite poles of the cell, pulled by microtubules
what happens in telophase?
the chromosomes begin to decondense
the spindle breaks down
the nuclear membranes and nucleoli re-form.
what happens in cytokinesis?
splits the parent cell into two identical daughter cells
what is meiosis used for?
allows sexual reproduction of diploid organisms
enables genetic diversity
aids the repair of genetic defects
how does meiosis provide genetic variety?
meiosis creates new combinations of genetic material in each of the four daughter cells
crossing over
the exchange of DNA between paired homologous chromosomes (one from each parent) that occurs during the development of egg and sperm cells (meiosis).
what are homologous pairs?
a set of one maternal and one paternal chromosome that pair up with each other inside a cell during fertilization
what are sister chromatids
two identical chromatids that are formed by replication of a chromosome
what are bivalents/recombinants?
2 sister chromatids