pdbio exam 4 Flashcards
In order for cells to grow they ____.
divide
As cells divide, genetic material (chromosomes) must be carefully duplicated, sorted and a copy passed to a new cell. The process whereby this occurs is called ____.
mitosis
Prokaryotes pass on their genetic information through ____.
Binary fission - dan replicates, moves to ends of cells, and cell pinches off into two.
Before a cell is dividing the DNA is found in the form of ____. Before replication the ____ condenses to form ____.
chromatin
chromatin
chromosomes
Chromosomes are made up of 3 things:
DNA, RNA, and protein
When a chromosome is duplicated and linked with its duplicate, the two pairs are known as ____.
sister chromatids
Mitosis involves the separation of the ____.
sister chromatids
The constriction point holding sister chromatids together is called the ____.
centromere
Whether in the x structure or the single structure, it is still called a ____.
chromosome
Humans have ____ pairs of chromosomes. (____ total chromosomes).
23 pairs
46 total
The 23 chromosomes from mom and the 23 chromosomes from dad are called _____ chromosomes.
Homologous
The 22 pairs of chromosomes in humans are called ____. The 23rd pair (xx or xy) is called ____.
22 autosomal pairs
1 pair of sex chromosomes
Diploid number
2n (two of each chromosome)
____ is a set of events for cell growth and division.
Cell cycle
The cell cycle is divided into 2 main sections:
interphase and mitotic (M) phase
3 parts of interphase
G1, S phase, G2 phase
What makes up the M phase?
mitosis and citokinesis
The majority of the cells life is spent in ____.
interphase
What happens during the G1 phase?
How many chromosomes are there in a human cell during the G1 phase?
- cell growth
- signaling molecules can cause cell to accumulate molecular changes that promote progression through the cycle
- if the cell passes the restriction point, or G1 checkpoint, the cell becomes committed to enter into S phase
- 46 chromosomes
What happens during S phase?
- chromosomes replicate
- after replication, two copies stay joined to each other and are called sister chromatids
What happens in the G2 phase?
How many chromosomes are there in a human cell during the G2 phase?
- cell synthesizes proteins needed for mitosis and cytokinesis
- 46 pairs of sister chromatids and 92 chromatids total
The decision of one cell nucleus into two, with separation of sister chromatids is what?
mitosis
Follows mitosis to divide the cytoplasm into two daughter cells?
cytokinesis
What determines the decision to divide?
External factors: -environmental conditions -signaling molecules Internal factors: -cell cycle control molecules -checkpoints
Proteins responsible for advancing a cell through the phases of the cell cycle
Cyclins or “cdks”
`What are the three checkpoints?
G1 checkpoint (restriction point) G2 checkpoint Metaphase checkpoint
Checkpoint proteins are ____ to determine if the cell is in proper condition to divide.
sensors
Loss of checkpoints can lead to what ?
mutations and cancer
In mitotic cell division, the cell divides to produce two new cells that are _____ to the original.
genetically identical
The original cell is called the _____ and the two new cells are called the _____.
mother cell
daughter cells
What is the way to remember the phases of mitosis?
PPMAT
What happens during interphase?
chromosomes are replicated
What happens during prophase?
chromosomes start to condense, mitotic spindle starts to form, nuclear envelope begins to dissociate.
What happens during prometaphase?
nuclear envelope is completely dissociated, mitotic spindle fully formed. Spindles attach to kinetochores on chromosomes.
What happens during metaphase?
sister chromatids along along metaphase plate
What happens during anaphase?
sister chromatids separate, and individual chromosomes move toward poles
What happens during telophase and cytokinesis?
nuclear envelope reforms. Cytokinesis separates mother cell into two daughter cells.
Chromosomes that are not sex chromosomes are called ____.
autosomes
In diploid cells, eukaryotic chromosomes occur in _____.
homologous pairs
Geneticists use the letter ____ to represent a set of chromosomes.
n