Chapter 16 - Cellular Reproduction Flashcards
Chromosome
When chromatin is tightly condensed, we call it a chromosome.
- visible under microscope
- not read easily
What is Chromatin?
Made up of DNA and proteins. The DNA is wrapped around proteins called histones.
- It’s uncondensed, and can be read easily.
- not visible under microscope.
Histones
Dna is wound around proteins called histones.
Resemble: “beads on a string”
- packaging of DNA
Nucleosomes
Groups of histones
Heredity
Traits are passed from parent to offspring.
How many chromosomes do humans have in one cell?
46
Chromatid
Each half of a duplicated chromosome is called a chromatid.
Sister chromatids
Identical strands connected by a centromere
Non-sister chromatids
Not attached by a centromere, not identical.
Centromere
Connects sister chromatids
When do we get a chromatin?
During interphase
When do we get a chromosome?
When a cell is dividing.
Rule for counting chromosomes:
Chromosomes are counted by counting centromeres.
- one centromere = one chromosome.
Rule for counting chromosomes:
Chromosomes are counted by counting centromeres.
- one centromere = one chromosome.
Homologous chromosomes
Similar-looking chromosomes that carry the same genes. Not identical because they carry different alleles.
Autosomes
All of the chromosomes except the sex chromosomes.
- chromosome pairs 1-22 = autosomes.
Sex chromosomes
Determine the sex of an individual (X and Y chromosomes)
Female
Two X chromosomes
Male
One X, one Y
Cell Cycle
The cell cycle is the sequence of activities that occurs from one cell division to the next.
Stages of cell cycle
The cell cycle is made up of two main stages: a growth stage and a division stage.
Growth Stage (Interphase) phases
- G1
- S
- G2
Where is most of the somatic cell’s life spent?
Interphase
G1 Phase
- the cell grows quickly during this phase
- most of cell’s life
- cells grows and carries out normal functions
G0 Phase
No more cell division. ex.) neurons
S Phase
Cell replicates DNA in preparation for mitosis.
G2 Phase
Cell prepares materials for mitosis and cell replication
- growth
- proteins are made
Cell Division
Two main processes in cell division:
1. Mitosis
2. Cytokinesis