exam 6 (ch 12,13) Flashcards
Microtubule organizing center
Centrosome
Actin filaments arranged in a twisted double chain
Microfilament
Tubulin proteins that make up part of the cytoskeleton
Microtubules
Proteins associated with DNA at the centromere
Kinetochore
Chromatin condense becoming sister chromatids (chromosomes), nucleus dissolves
Prophase
Sister chromatids line up in the middle of the cell
Metaphase
The plane where chromosomes line up due to the pull from microtubules
Metaphase Plate
Sister chromatids separate
Anaphase
The cells start to separate
in animals: a cleavage furrow forms
Telophase
How does cytokinesis occur in animals?
A cleavage furrow forms from the pull of actin and myosin microfilaments
What cells undergo mitosis?
Single-celled organisms for asexual reproduction, a fertilized egg cell, cells in our body (to make more of the same cell, to repair damaged cells)
Develop when a cell undergoes transformation and evades detection
-May have an unusual number of chromosomes
-Lose attachment to neighboring cells
Stimulates blood vessel growth towards tumor
Cancer Cells
A few cells may separate and enter blood vessels, causing cancer somewhere else
Metastasis
Cannot spread beyond original tissue
Benign Tumors
Can spread to new tissues
Malignant Tumors
Damages DNA
-Affects cancer cells more than regular cells, presumably cancer cells have lost their DNA repair mechanisms
Radiation
Interfere with the cell cycle of cells–not just cancer cells
- Results in hair loss from effects on hair follicle cells
- Affects susceptibility to infection from effects on immune system
Chemotherapy Drugs
Since prokaryotes do not have a nucleus, they go through a method of asexual reproduction by “division in half,” does not involve mitosis
Binary Fission
Unregulated cell growth
Cancer
Division of cytoplasm
Cytokinesis
Replication of DNA
S phase
Nuclear division (nucleus dividing)
Mitosis
Preparation for cell division
G2 phase
Normal cell operations and cell growth
G1 phase
2 copies of every gene, cell has homologous pairs of chromosomes
Diploid
1 copy of every gene, cell has single chromatids or sister chromatids; no homologous pairs
Haploid
A region of the chromosomal DNA where the chromatid is attached most closely to its sister chromatid
Centromere
Pair of separate DNA strands that carry genes for same traits, not attached physically
Homologous pairs
Joined copies of the original chromosome
Sister chromatids
One unit of condensed chromatin
Chromatid
DNA and proteins that are coiled together
Chromatin
Duplicated homologous chromosomes pair and exchange segments
Prophase 1
Homologous pairs line up
Metaphase 1
Homologous chromosomes sort independently/randomly with respect to other chromosomes, occurs during metaphase 1
Independent Assortment
When is the rule of independent assortment broken?
When chromosomes are near each other on the same chromatid
Homlogous pairs separate
Anaphase 1
2 haploid cells form; each chromosome still consists of 2 sister chromatids
Telophase 1
A spindle apparatus forms
Prophase 2
Sister chromatids line up
Metaphase 2
Sister chromatids separate
Anaphase 2
Haploid cells are forming, nuclei form, chromosomes begin decondensing and cytokinesis occurs
Telophase 2
Results in 4 haploid daughter cells, daughter cells not identical, typically develop into egg and sperm
Meiosis
Tips of homologous pairs of chromosomes are exchanged, occurs during prophase 1, results in greater diversity among daughter cells and offspring
Crossing Over
What are 3 ways daughter cells produced by meiosis can be different from each other?
- Independent assortment
- Crossing over
- Mutation
When cells stop dividing when they come into contact with one another
Density Dependence Inhibition
Animal cells must be attached to something in order to divide
Anchorage Dependence
What would happen if sexual reproduction occurred without meiosis?
There would be too much DNA in the cell
