Study Guides (248,581)
Biology (1,112)
BIOL 308 (101)

# Study_question_for_lectures_8___9.doc

6 Pages
144 Views

School
Department
Biology
Course
BIOL 308
Professor
Dragana Miskovic
Semester
Fall

Description
Study questions for the lectures 8-9 1. The human gametes have about 3 billion bp of DNA in their chromosomes. a. Express the size of the diploid genome in kb (kilo bases; 1kb = 1000bp)  Human gamete = haploid genome = 3 billion bp of DNA in their chromosomes  Diploid genome = 2 x 3 billion bp = 6 million kb of DNA in their chromosomes b. If the entire DNA was in relaxed B-DNA form, what would be the average length of a chromosome expressed in cm?  Since B-DNA is approx. 10 bp/turn and each turn is every 3.4 nm, each bp is 0.34 nm apart  6 billion bp / 46 chromosomes = 130 million bp/chromosome  130 million bp x 0.34 nm = 44 million nm x 10 = 4.4 cm c. On average, how many complete turns would be in each chromosome?  4.4 cm = 44,000,000 nm  44,000,000 nm / 3.4 nm/turn = 13 million complete turns d. If there are around 30-40,000 genes in a human gamete, how many genes are there in an average chromosome?  If there is 30-40,000 genes and 23 chromosomes in a human gamete (haploid),  30-40,000 genes/gamete ÷ 23 chromosomes/gamete = 1304–1739 genes/chromosome 2. Define homologous chromosomes.  Chromosomes that are identical in size, shape, and banding pattern (each derived from 1 parent), and carry the same genes but may have different alleles 3. Define non-homologous chromosomes.  Chromosomes that differ in size, shape, and banding pattern, and carry different genes 4. How many homologous chromosomes are there in a germ cell of a woman? Of a man?  There are 23 homologous chromosomes in the germ cell of a woman (22 homologous autosomal chromosomes + 1 homologous sex chromosome XX)  There are 22 homologous chromosomes in the germ cell of a man (not 23 like in women because the male sex chromosomes XY are not homologous) 5. Distinguish between homologous chromosomes and sister chromatids.  Homologous chromosomes: 2 non-identical chromosomes that match in size, shape, and banding pattern (each derived from 1 parent); they carry the same genes but may have different alleles  Sister chromatids: 2 identical copies of a chromosome that exist immediately after DNA replication 6. What is the purpose of cell division in Prokaryotes? In Eukaryotes?  Prokaryotes: the purpose of cell division is reproduction  Eukaryotes: the purpose of cell division is tissue growth and repair of damaged tissues (via mitosis), and reproduction (via meiosis) 7. Distinguish between DNA replication and cell division.  DNA replication occurs during S phase of the cell cycle as chromosomes duplicate (in which 2 identical copies of DNA are produced from one DNA molecule) 1 cell remains as 1  Cell division occurs at the end of the M phase (mitosis) in which the parent cell divides into 2 daughter cells 1 cell is split into 2 cells 8. Distinguish between reason/purpose for/of mitosis and reason/purpose for/of meiosis?  The purpose of mitosis is tissue growth and repair of damaged tissues by producing daughter cells that are identical to the parent cell no variabiliy  The purpose of meiosis is reproduction to form gametes that are not identical to each other or to the parent cell; the goal is to preserve information while keeping/making it variable at the same time variability due to independent assortment of homologous chromosomes 9. How is variability of genetic information attained by meiosis and fertilization?  Variability in meiosis is due to independent assortment of homologous chromosomes (different arrangements of chromosomes at metaphase I and II in meiosis)  Variability is also due to crossing over of homologous chromosomes in prophase I during meiosis  Variability of genetic information occurs in fertilization due to the fusion of 1 haploid cell from the mother and 1 haploid cell from the father 10. What is a cell cycle? What are the stages of cell cycle?  The cell cycle is the orderly set of events that take place between the formation of a new cell and the division of that “parent” cell into 2 new “daughter” cells  Stages of the cell cycle: o G 1hase: cell growth occurs as organelles double (chromosomes are unipartite) o S phase: DNA replication occurs as chromosomes duplicate (chromosomes are bipartite) o G 2hase: cell growth occurs as cell prepares to divide
More Less

Related notes for BIOL 308
Me

OR

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Join to view

OR

By registering, I agree to the Terms and Privacy Policies
Just a few more details

So we can recommend you notes for your school.