Biology Test Two Flashcards
Cell cycle description
Process by which a cell reproduces itself.
Cell cycle phases
Interphase
Mitosis and cytokinesis
Cell cycle purpose
Producing sufficient ingredients such as organelles, cytoplasm, and DNA to make two new daughter cells.
Segregating a complete copy of those ingredients to each daughter cell to create two genetically identical cells.
Mitosis products
Two identical daughter cells
Mitosis sub divisions
Prophase
Metaphase
Anaphase
Telophase
Number of chromosomes
46
23 pairs
Why cell division is important
For normal growth, development, and repair of organisms.
Heals wounds
Cell checkpoints
G1-S
G2-M
M-A
Cell checkpoint jobs
Monitor each stage of cell cycle and check for mistakes such as DNA damage.
Prevent a cell from progressing to next stage until it accurately finishes current stage
Cell cycle checkpoint two mechanisms in regulating the cycle
If DNA damage is detected at checkpoint, a cell conducts DNA repair mechanism to repair damage.
If case is severe or irreversible damage, cp directs cell to commit suicide or apoptosis
Cancer cells caused by….
Specific proteins sometimes become damaged and can’t detect DNA damage. Cells can divide over and over again causing cancer.
Cancer is a disease of unregulated cell division. Inappropriate cell division and cells divide
Methods of fighting cancer
Chemotherapy- treatment that interferes with the cell cycle
Plant derived drugs- Interfere with chromosome separation during mitosis
Radiation therapy- beams of high energy electrons that kill dividing cells in specific area. Severely damages molecules and DNA.
Meiosis products
Gametes (sex cells)
4 genetically unique haploid gametes (daughter cells)
Purpose of meiosis
To halve the chromosome number from 46 to 23
Gametes
Sperm or egg are specialized reproductive cells that carry one copy of each chromosome. Haploid. Carry 23 chromosomes.
Order of events in Meiosis
When haploid sperm fertilizes a haploid egg, the result is a diploid zygote.
The zygote carries 2 copies of every chromosome and 2 copies of every gene on 46 chromosomes or 23 pairs.
Zygote will divide by mitosis to become an embryo
That will eventually grow into a human child.
Gene
Physically transmitted from parents to children.
Sequence of DNA that contains information to make up at least one protein.
Allele
Alternative version of the same gene that have different nucleotide sequences and are on homologous chromosomes.
Ex. Ff FF ff
Ff is gene and F is allele and f is allele.
Genotype
Genetic makeup of an organism
Ex. Blood AA, AO, BO…..
Phenotype
Visible traits or physical appearance of an individual
Ex. Curly hair
Dominant allele
An allele that can mask the trait of a recessive allele
Dark eyes
Curly hair
Freckles
Dimples
Recessive allele
Allele that reveals itself in the phenotype only of the organism has two copies of that allele.
Tongue rolling
Straight hair
Blue eyes