chapter 8 Flashcards
What is DNA replication
The process by which a cell copies its DNA before dividing so that each new cell has a complete set of DNA
What is meant by a semiconservative model of DNA replication?
A DNA double helix that includes one complete strand from the original molecule
What is the functions of DNA helicase,
unwinds the double helix
What is the functions of DNA polymerase
adds nucleotides to form new strands
What is the functions of DNA ligase?
forms covalent bonds between adjacent DNA segments
What are the functions of binding proteins and primase?
BP: stabilizes each strand, preventing them from rejoining
Primase: makes a short stretch of RNA on the DNA template
What are leading strands?
A leading strand is when replication proceeds continuously on only one new DNA strand
What are lagging strands?
When replication occurs in short 5’ to 3’ pieces
What is a replication fork
When the DNA is unwound by DNA helicase it creates a y-shaped region where the two strands are separated.
What are Okazaki fragments?
short pieces of DNA formed by the lagging strands
In which direction is DNA replication continuous?
5’ to 3’ direction
What are the parent and daughter strands?
Parental strands: The original DNA strands that serve as templates for the new strands
Daughter strands: The new DNA strands that are synthesized from the parental strands
What is a replication “bubble?”
An open region of DNA where DNA replication occurs.
What is binary fission?
type of asexual reproduction in which a prokaryotic cell divides into two identical cells
What are the four stages of binary
fission of prokaryotes?
duplication, elongation, pinching/deposition,
and division
What are mitosis and meiosis?
Mit- one way cells reproduce
mei- another way a nucleus divides
What are two functions of cell division?
1) So life can continue
2) growth
What are two reasons that
chromosomes condense before cell division?
1) to be transported easier
2) to be able to be copied
what are histones
A protein (8 forms a nucleosome)
what are nucleosomes
its a spool that DNA wraps around
what are centromeres?
attaches sister chromatids to each other.
What is the cell cycle
The life cycle of the cell
What is interphase
(A resting phase) where the cell replicates dna and grows
What generally occurs during G1, S, G2?
G1: The cell grows
S: DNA is synthesized
G2: Cell continues to grow
What is the difference between mitosis and cytokinesis?
Mitosis is nuclear division and cytokinesis is cellular division
When does cytokinesis begin?
Begins during telophase
What general events occur during prophase
The nucleus dissolves and chromosomes condense
What general events occur during prometaphase
The phase between prophase and metaphase that explains how the chromosomes get to the middle
What general events occur during metaphase,
chromosomes line up at the equator of the cell
What general events occur during
anaphase
Where copies of the chromosomes are being separated
What general events occur during telophase?
New nucleus forms and chromosomes unravel
What is the mitotic spindle and when does it form?
Its a structure made of microtubules and Forms in prophase
What are kinetochores
A structure that microtubules attach too
How do animal cells undergo cytokinesis?
The cleavage furrow is when the animal cell pinches itself to undergo cytokinesis
How do plant cells undergo cytokinesis?
Plant cells have to create a cell plate to undergo cytokinesis
here in the cell cycle are the four major checkpoints?
G1/S checkpoint:
Intra-S checkpoint:
G2/M checkpoint:
M (metaphase) checkpoint:
What are tumors?
A tumor is a abnormal mass of tissue resulting from cells dividing out of control
What are benign tumors and malignant tumors?
B: mass of abnormal cells that do not have the potential to spread
m: mass of abnormal cells that has the potential to spread throughout the body
