Chapter 12
What is a genome?
the complete set of genes or genetic material present in a cell or organism.
The two sister chromatids are attached at the _______________.
centromere
Phenotype vs Genotype
Genotype is the combination of alleles an individual contains, while phenotype is the physical appearance.
Genes located near each other on the same chromosome tend to be inherited together and are called
linked genes
What are the 3 parts of a nucleotide?
Phosphate group, ribose or deoxyribose sugar, nucleotide base.
The condensed histone protein-DNA complex is called
Chromatin.
Name the common five stages of mitosis and meiosis I.
Prophase, prometaphase, metaphase, anaphase, and telophase.
What is meant by P, F1 and F2 generations?
The true-breeding parents are referred to as the P generation (parental generation), and their hybrid offspring are the F1 generation (first filial generation, the word filial from the Latin word for “son”). Allowing these hybrids to self-pollinate (or to cross-pollinate with other hybrids) produces an F2 generation (second filial generation).
Define genetic recombination.
Genetic recombination (also known as genetic reshuffling) is the exchange of genetic material between different organisms which leads to production of offspring with combinations of traits that differ from those found in either parent.
Which bases are pyrimidines and purines and what pairs with what?
pyrimidines: T and C
purine: A and G
A pairs with T
G pairs with C
Differentiate among human somatic cells and gametes? How many chromosomes are present in both?
Somatic cells are non-reproductive cells that have two sets of chromosomes, whereas gametes are reproductive cells such as sperm and eggs and have one set or half as many chromosomes as somatic cells. 46 somatic and 23 gametic.
Prokaryotes produce by a type of cell division known as
binary fission.
What is Mendel’s law of independent assortment?
What is the purpose of a Barr body?
How does replication start? What prevents the unwound DNA for twisting back?
Helicase unzips DNA, single stranded binding proteins keep it unzipped.
During the interphase DNA is in _________ form and during M phase DNA is in _______ form.
1. chromatin
2. chromosome
M checkpoint:
This occurs in mitosis near the end of metaphase. It checks whether the sister chromatids are correctly attached to the spindle fibers before the cell enters the irreversible anaphase stage.
What does Mendel’s law of segregation state?
It states that the two alleles for a heritable character segregate (separate from each other) during gamete formation and end up in different gametes. Thus, an egg or a sperm gets only one of the two alleles that are present in the somatic cells of the organism making the gamete. One allele from each parent for each gene.
________is a condition in which an organism has more than two complete sets of chromosomes
Polyploidy
Identify the enzyme called as molecular glue that joins the okazaki fragments by forming phosphodiester bonds is
ligase
What do you know about Interphase? What are its subphases and what do they stand for?
Interphase is where cells spend about 90% of their time. G1 phase is the “first gap”, S phase is for synthesis and that is where the chromosomes are duplicated. The G2 phase is the “second gap.”
3 differences between mitosis and meiosis.
In a cross between a white-eyed female fruit fly and red-eyed male, what percent of the female offspring will have white eyes? (White eyes are X-linked, recessive).
0%
What happens in nondisjunction?
pairs of homologous chromosomes (a) OR sister chromatids (b) do not separate normally during meiosis
Why the two strands of the helix have to be elongated by two slightly different mechanisms?