Cell Division And The Cell Cycle Slides 1-19 Flashcards
Aspects of asexual reproduction
Offspring identical to the original cell or organism (clone)
One parent
No sperm or Egg
Aspects of sexual reproduction
Variations from parents
Involves 2 parents
Fusion of gametes and egg and sperm
Meiosis
Eukaryotic Cells
DNA found in nucleus DNA made up of chromosomes Cell division- Mitosis Multi-cellular More complex (human carries 25,000 genes)
Prokaryotic Cells
Reproduce by Binary Fission Single cell (unicellular) DNA floats in cytoplasm DNA strand (coiled/circular) No nucleus Less complex (bacteria carries 3,000 genes)
Define binary fission
Reproduces prokaryotes Cells by dividing in half
Steps of binary fission
- Chromosome duplicates, copies separate
- Cell continues to elongate, copies move apart
- Membrane grows inward to divide the cells
What is the name of the protein that helps DNA condense into chromosomes?
Histones
During what phase do chromosomes become condensed?
Metaphase
Describe how the DNA of chromatin becomes condensed.
The chromatin is wrapped around a complex histones
What are eukaryotic Cells composed of?
Chromatin
What is chromatin made up of?
DNA and proteins called histones
Eukaryotic cell division steps
- Cell duplicates all its chromosomes
- When cell divides sister chromatids separate
- Once sedated each chromatid is called a chromosome
What are the two copies of a chromosome called?
Chromatid
What do sister chromatids contain?
Incentivar copies of the dna molecule
Where are chromatids joined at?
The centromere
What is the basis of reproduction for every organism?
Cell division
What does cell division enable?
Multicellular organisms grow to adult size
What does cell division help to replace?
Worn out or damaged cells
What does cell division keep consistent?
The total number of cells in a mature organism
How big apart of the cell cycle is mitosis?
A small fraction of the cell cycle
Define the cell cycle
An order sequence of events that lead to cell division
What are the two states of the cell cycle?
Interphase (90%) Mitotic phase (10%)
What are the parts of interphase?
G1, S and G2
What is interphase?
Duplication of cell contents
G1
Growth, increase in cytoplasm
S
Duplication of chromosomes
G2
Growth, preparation for division
Mitotic Phase
Division
What are the parts of the mitotic phase?
Mitosis
Cytokinesis
Mitosis
Division of the nucleus
Cytokinesis
Division of cytoplasm
Stages of mitosis
Prophase Prometaphase Metaphase Anaphase Telophase
Control points where signals regulate the cell cycle
Checkpoints
What are the checkpoints
G1
G2
M
What is the G1 checkpoint
Allows entry into the S phase or causes the cell to leave the cycle entering a nondividing G0 phase
What types of cells go int G0 phase
Nerve and muscle cells
What makes precancerous cells different from normal cells
Precancerous Cell follow own directions, regular cells usually grow, die and reproduce, cancerous cells divide more often then a regular cells, uncontrollable
How do cancer cells move to a new location
Cancer cells move through the blood stream to new locations
What are the four stages of the cell cycle
G1(Mose important checkpoint)
S(synthesis)
G2
Mitosis
During which phase do cells divide
Mitosis
In normal cells cell division is precisely controlled by ______________
Internal clocks
What genes are accelerators of cell division
Protooncogenes
What genes are the breaks of cells division
Tumor suppressors
What is controlled
Cell division
What does controlled cell division allow for
Normal growth and development of tissues
What happens if cell division doesn’t have control
They can divide excessively
What can excessive cell division cause
Invasion of normal fussed of the body
Cancer cells divide in the absence of _________
Growth factors
How do cancer cells spread to other tissues
Circulatory System
What forms when growth is not inhibited by other cells
Tumors
Benign tumors
Remain at the original site
Malignant tumors
Spread to other locations by metastasis
Cancer treatments
Surgery (localized)-> can damage surrounding tissues
radiation (localized) -> kills all cells in area
Chemotherapy (spread)-> kills all cells
External/internal body coverings
Carcinomas
Supportive and connective tissues
Sarcomas
Blood forming tissues
Leukemia’s and lymphomas
Somatic Cells
Body cells
Includes all the cells in body except egg and sperm
Human somatic cells contain 46 chromosomes
Somatic chromosomes have pairs of homologous chromosomes (one from each parent)
Autosomes
Same size and genetic composition
Except for sex chromosomes (XandY differ and size and genetic composition)
How many pairs of sex chromosomes do humans have
One pair
Diploid Cells
Have 2 homologous sets of chromosomes (somatic cells)
Haploid Cells
Have one set of chromosomes (gametes)
Gametes
Egg and sperm have haploid (n) chromosome number
Zygote
Has diploid (2n) chromosomes number, one set from each parent
Zygote can develop into multi cellular adult during
Mitosis
Creates gamete
Meiosis
Karyotype
An ordered display of magnified images of an individuals chromosomes arranged in pairs, abnormalities can be detected by this, shown as condensed and doubled
What can be found from karyotype?
Sex
Abnormalities
How many chromosomes are organized into how many pairs in human?
46 into 23 pairs
Autosomes are numbered from what to what in humans
1-22
Sex chromomosems are 23
What shows band patterns
Stained chromosomes
Female
XX
Male
XY
What is the cause of Down syndrome
Trisomy 21
3 copies on 21 chromosome
Nondisjunction
Failure or chromosomes or chromatids to separate during meiosis
