Chapter 2- Reproduction Flashcards
Germline vs Autosomal Cells
Diploid (2n) vs Haploid (n)
Number of chromosomes
Autosomal (2n) 46 chromosomes
Germline (n) 23 chromosomes
Stages of the Cell Cycle
G1 organelles produced, cell growth, restriction point 1
S dna replication (chromatids replicate 46 chromosomes)
G2 growth, restriction point 2
M Mitosis and Cytokinesis
What are the total number of chromosomes after the S phase of the cell cycle?
46
What stages of the cell cycle are the two quality checkpoints?
The restriction points are between the do you want an S phase and a G2 and M phase of the cell cycle
What proteins assist with the restriction checkpoints of the cell cycle?
p53
What molecules are responsible for the cell cycle?
Cyclins and Cyclin dependent kinases
Ultimately lead to phosphorylation on transcription factors
How do CDK’s promote transcription
Cyclins bind to cyclin dependent kinases in order to activate the CDK – cyclone complex. The complex can then phosphorylate transcription factors in the transcription factors promote transcription of genes required for the next stage of the cell cycle.
What is the gene mutation most commonly found in cancer?
Mutation in the TP53 gene that produces p53
What are the four phases of mitosis?
Prophase
Metaphase
Anaphase
Telophase
Mitosis only occurs in what cells?
Somatic cells (cells not involved in sexual reproduction)
Prophase
🤍Nuclear membrane dissolves
🤍Chromosomes condense
🤍Centriole pairs separate and move to opposite poles of the cell
🤍Spindles/kinetochore form (microtubules)
Metaphase
Kinetochore fibers interact with spindle fiber apparatus
Chromosomes align af equitorial plate (metaphase plate)
Anaphase
Centromeres split and sister chromatids separate and are pulled toward opposite sides of the cell by the shortening of the kinetichore fibers
Telophase and Cytokinesis
Spindle apparatus disappears
Nuclear membrane reforms Chromosomes uncoil
Separation of the cytoplasm so that each daughter cell has enough material to survive on his own
Meiosis occurs in ____________ cells.
Gameteocytes (germ cells)
Meiosis I
Homologous chromosomes separate resulting in 2 haploid daughter cells
Meiosis II
Similar to meiosis separation of chromosomes resulting in haploid daughter cells
The human genome consists of how many homologous pairs of chromosomes?
23
After S phase, what is the number of chromatids, chromosomes, homologous pairs?
96,46,23
What special things occurs at prophase one?
Formation of tetrads in a process called synapsis.
Crossing over the chromatids of homologous chromosomes break at the chiasma and exchange equivalent pieces of DNA.
What proteins holds together homologous chromosomes in a tetrad?
Sunaptomemal complex
Does crossing over occur between sister chromatids or homologous chromosomes?
Crossing over occurs between homologous chromosomes. Crossing over of sister chromatids would not produce any change.
Are genes that are located closer together or farther apart more likely to undergo crossing over?
Genes that are located farther apart are more likely to undergo crossing over and thus less likely to be inherited together.
Mendeld second law
Law of independent assortment
Inheritance of one allele has no effect on the likelihood of inheriting certain alleles for other genes.
Mendels first law of segregation
Law of Segregation
Distribution of homologous chromosomes to the intermediate daughter cell is random with respect to parental origin
What is disjunction and when does it occur in meiosis?
Anaphase 1 of meiosis 1
Each chromosome of parental origin separates from its homologue of maternal origin and the daughter cell can inherit either chromosome randomly.
Sex chromosomes are which number in the human genome?
23rd pair of chromosomes
What gene is found on the Y chromosome that determines sex?
SRY (Sex determining region Y) codes for a transcription factor that initiates testis differentiation and formation of male gonads.
What two components make up the testes?
Seminiferous tubules, interstitial cells of leydig
What structure helps elevate and lower the testes to maintain an optimal temperature?
Layer of muscle around the vas deferens
What structures combined produces seminal fluid?
Bulbourethal gland, seminal vesicles, prostate gland
Seminal vesicles secrete
Seminal fluid, fructose to nourish sperm as well as alkaline fluid
Bulbourethral glands secrete
Seminal fluid and clear fluid that cleans out urine during sexual arousal
Prostage gland secretes
Seminal fluid, alkaline fluid
Which part of the sperm produces ATP from fructose?
Midpiece (filled with mitochondria
Eggs are ovulated into what area?
Peritoneal sac
Which structure surrounds the oocyte itself and protects it?
Zona pellucide
Surrounded by Corona radiata
What causes ovarian atrophy in menopause?
Ovaries become less were sponsored to FSH and LH. Drop in estrogen and progesterone levels causes atrophy of the endometrium.
What age is menopause?
45-55
