BIOL 102 Study Guide - Midterm Guide: Spindle Apparatus, Sister Chromatids, Cleavage Furrow
How is the cell cycle controlled?
● Normal plant and animal cells have a cell cycle control system
● Checkpoints in cell cycle
● Specialized proteins
o Stop and go-ahead signals
o Key points during the cell cycle
● (Extra)
o Chroosoes: struture that otais ost of the ell’s DNA
o Gametes: egg and sperm
o Chromatin: chromosomes are made up of chromatin, fibers composed of roughly equal
amounts of DNA and protein molecules; the protein molecules help organize the
chromatin and help control the activity of ties genes.
o Histones: package and order the DNA into nucleosomes(beads in DNA packing)
o Interphase: double everything in cytoplasm
▪ S phrase: chromosome duplication
▪ G2: each chromosome in the cell consists of two identical sister chromatids and
cell prepares to divide
o Mitotic phase(cell dividing):
▪ Mitosis: divide into two daughter nuclei
● Prophase: mitotic spindle begins to form, nuclear envelope breaks, 2
sister chromatids
● Metaphase: align in the center
● Anaphase: sister chromatids of each chromosome separate, moves
towards opposite poles
● Telophase: at opposite poles, spindle disappears, cleavage furrow
▪ Cytokinesis: cytoplasm divide in two cell or cell plate
What is Cancer?
● Cancer is a disease of the cell cycle
o Abnormal response to cell cycle control
● Tumors=abnormally growing masses of cells
● Benign tumors
o Abnormal cells remain at the original state
o Okay if they are removed
● Malignant tumors
o Spread beyond site of origin
o Interfere with normal function of cells, tissues, and organs
o Spreads and invade
How are cancers treated?
● Surgery
● Treatments attack rapidly dividing cells
● Radiation therapy
o Damages DNA
o Disrupts cell division
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o Can target specific tumor, but can still damage
● Chemotherapy
o Drugs that disrupt cell division
o Interfere with the mitotic spindle
o Does’t target ell, goes through stoah ad lots of the od
● Cancer cells divide rapidly and out of control
Cancer Prevention (Certain behavior can decrease the risk of cancer)
● Not smoking
o 70/250 chemicals in smoke are carcinogenic
o Nicotine=poison and has indirect cancer promoting effects
● Adequate exercise and sleep
o Exercise promotes hormonal balance
o Less than 6 hours sleep increase cancer risk
● Avoiding exposure to the sun
o UV damages DNA
● High-fiber, low-fat diet
o Fier seeps the olo akes elluloses, our od a’t digest it so it gets seep out
along with other stuff)
o Increase fat in diet increases estrogen (affects breast and ovaries)
What exactly is sexual reproduction?
● Recombination of genetic material
● Requires two individual(parents)
o Offspring have unique combinations of genes
● Alternation of meiosis and fertilization (processes)
● Alternation of haploid(halves) and diploid states (wholes) (chromosome number)
● Zygote= product of egg and sperm
Distinguish between haploid and diploid
● Haploid (n)
o One set of chromosomes
o Gametes(egg and sperm) (only half cells in humans and animals)
o 23
● Diploid (2n)
o Two sets of chromosomes
o Somatic cells
o 46
What are homologous chromosomes? What are alleles?
● Homologous chromosomes
o Are matching pairs or sets of chromosomes
▪ Not chromatids
o Can possess the same or different versions of the same genes
o Alleles= different version of the same gene
What is a karyotype?
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● Orderly array of chromosomes of an individual
Chromosome number
● Individuals of a single species have the same number of different chromosomes
● Diploid numbers, 2n
What is the difference between autosomes and sex chromosomes?
● Humans have 23 different kinds of chromosomes
o 22 pairs of homologous chromosomes or autosomes
o One pair of sex chromosomes
o XX (female
o XY (male)
● Autosomes are not the X or Y (other 44 chromosomes)
What is the cycle in animals?
● Sequence of stages
o Adults of one generation to adults of next generation
● Meiosis and fertilization: sexual life cycle
o Gametes produced by meiosis: 2nn
▪ Prevents doubling of chromosomes number
o Zygote produced by fertilization n2n
● Mitosis takes place during growth and development
● Memorize meiosis stage
What happens during meiosis?
● As in mitosis, chromosomes are duplicated during the interphase before meiosis
● Two consecutive nuclear and cytoplasmic divisions follow
o Meiosis 1
▪ Non sister chromatids cross-over in Prophase 1
▪ Homologous chromosomes separate in Anaphase 1
o Meiosis 2
▪ Chromatids separate in Anaphase 2 as in mitosis
What’s the differee etee itosis ad eiosis
● In mitosis and meiosis: chromosomes duplicate once, during the preceding interphase.
● The number of cell divisions is different
o Mitosis: cell divides once and produces 2 diploid cells
o Meiosis: cell divides twice and produces 4 haploid cells
▪ Crossing over of non-sister chromatids during Prophases 1
▪ Alignment of homologous pair during metaphase 1
How genetic variation increased?
● Why is variation important?
● Offspring of sexual reproduction are genetically different from their parents and one another
o Crossing over during prophase 1
o Independent assortment of chromosomes
o Random fertilization
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Document Summary
Normal plant and animal cells have a cell cycle control system. S phrase: chromosome duplication: g2: each chromosome in the cell consists of two identical sister chromatids and cell prepares to divide, mitotic phase(cell dividing), mitosis: divide into two daughter nuclei. Prophase: mitotic spindle begins to form, nuclear envelope breaks, 2 sister chromatids. Anaphase: sister chromatids of each chromosome separate, moves towards opposite poles. Telophase: at opposite poles, spindle disappears, cleavage furrow: cytokinesis: cytoplasm divide in two cell or cell plate. Cancer is a disease of the cell cycle: abnormal response to cell cycle control. Benign tumors: abnormal cells remain at the original state, okay if they are removed. Malignant tumors: spread beyond site of origin. Interfere with normal function of cells, tissues, and organs: spreads and invade. Radiation therapy: damages dna, disrupts cell division, can target specific tumor, but can still damage. Chemotherapy: drugs that disrupt cell division.
