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110 Cards in this Set
- Front
- Back
- 3rd side (hint)
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What is cellular division? |
The ability of organisms to produce more of their own kind |
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What is cellular division in unicellular organisms? |
Division of one cell reproduces the entire organism. |
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What is cellular division in eukaryotes? |
Development from a fertilized egg, growth, repair |
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What is the definition of the cell cycle? |
The life of a cell from formation to it’s own division. |
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What does most cell division result in? |
Two daughter cells with identical genetic information |
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What is the exception to cell division? |
Meiosis |
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What is meiosis? |
A special type of division that can produce sperm and egg cells, which produces non-identical daughter cells |
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What is a genome? |
All the DNA in a cell |
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What does the genome consist of? |
A single DNA molecule (common in prokaryotic cells) or a number of DNA molecules (common in eukaryotic cells) |
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What makes up eukaryotic chromosomes? |
Chromatin |
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What is chromatin? |
A complex of DNA and protein (histones) that condenses during cell division. |
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What happens in preparation for cell division? |
DNA is replicated and the chromosomes condense |
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What does each duplicated chromosome have? |
Two sister chromatids |
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What are sister chromatids? |
Joined copies of the original chromosome, attached along their lengths by cohesins |
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What are cohesins? |
Protein complexes that attach sister chromatids |
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What is the centromere? |
The narrow waist of the duplicated chromosome where the two chromatids are most closely attached |
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What do the two chromatids do during CD? |
Separate and move into two new nuclei |
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What are chromatids called once separated? |
Chromosomes |
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What are the two major phases of the cell cycle? |
Interphase and mitotic phase (mitosis and cytokinesis) |
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What is interphase? (G1, S, and G2) |
Cell growth and copying of chromosomes in preparations for cell division. |
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What is mitosis? |
The division of the genetic material in the nucleus. |
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What is cytokinesis? |
The division of the cytoplasm |
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What portion of the cell cycle does interphase comprise? |
About 90% of the cell cycle Cell grows during all 3 phases, but chromosomes are duplicated only during S phase |
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What is G1 phase? |
First gap, cells increase in size, get ready for the S phase |
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What is S phase? |
Synthesis, DNA replication occurs |
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What is G2 phase? |
Second gap, cells continue to grow, gets ready for mitosis. |
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What happens to the nucleus in G2 of interphase? |
A nuclear envelope encloses the nucleus. |
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In G2, what do the centromeres do? |
They form regions that organize microtubules |
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What is odd about chromosomes in S phase? |
They cannot be seen because they have not been condensed. |
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In prophase, what happens to chromatin fibres? |
They tightly coil into discrete chromosomes, becoming visible |
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In prophase, how do chromosomes appear? |
Appear as two sister chromatids joined at centromeres. |
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In Prophase, what begins to form? |
The mitotic spindle begins to form and the centromeres move away from each other. |
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In Prometaphase, what happens to the nuclear envelope? |
It fragments |
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How do microtubules behave in prometaphase? |
Microtubules from each centrosome invade the nuclear area and the chromosomes become more condensed |
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What is a kinetichore? |
Protein structure at the centromere on each sister chromatid. |
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What do non kinetichore microtubules do? |
They elongate the cell |
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What happens in metaphase? |
Centrosomes are at the opposites poles of the cells |
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What is the metaphase plate, and what happens when chromosomes arrive there in Metaphase? |
It is an imaginary plane at the middle of the cell. Centromeres lie at the metaphase plate. |
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What happens in Anaphase? |
Cohesins between chromatids are cleaved, allowing each pair to separate (becoming an independent chromosome) |
Shortest phase of mitosis |
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Summarize mitosis in 4 points |
- two daughter nuclei form - nuclear envelope reappears - chromosomes start to decondense - mitosis is now complete, creating two genetically identical nuclei |
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Summarize cytokinesis in 2 points |
Division of the cytoplasm Involves formation of a cleavage furrow, pinching cell in two. |
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What is the mitotic spindle? |
A structure made of microtubules that controls chromosome movement during mitosis |
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In animals, where does assembly of spindle microtubules begin? |
Begins at the centrosome. Microtubules organizing centre MTOC |
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What happens to the centrosome? |
Replicates during interphase The centrosomes migrate to opposite ends of the cell during prophase and prometaphase |
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What happens to the mitotic spindle during prometaphase? |
Some spindle microtubules attach to the kinetochores of chromosomes and begin to move the chromosomes |
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What are kinetochores? |
Protein complexes associated with centromeres. |
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What happens to the cohesins in anaphase? |
The cohesins are cleaved by an enzyme called separase |
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How do sister chromatids move in anaphase? |
The separate and move along the kinetochore microtubules toward opposite ends of the cell |
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How do the microtubules shorten during anaphase? |
Depolymerization at their kinetochore ends. |
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When does cytokinesis begin? What happens to the spindle? |
During anaphase or telophase, and the spindle eventually disassembles |
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How does cytokinesis occur in animal cells? |
By a process known as cleavage, forming a cleavage furrow |
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What forms in a plant cell during cytokinesis? |
A cell plate forms Derived from the Golgi apparatus |
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What drives the cell cycle? |
Specific chemical signals present in the cytoplasm |
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What directs the cell cycle? |
The cell cycle control system, which is similar to a clock |
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What does the “clock” have? |
Checkpoints. The cell cycle stops until a go-ahead signal is received. |
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Changes in “what” drives the cell cycle |
Changes in regulatory protein concentrations drives the cell cycle |
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What are the 3 important checkpoints? |
The ones in the G1, G2, and M phases |
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What happens if the cell does not receive the go-ahead? |
It will exit the cycle, switching to a non-dividing state called the G0 phase. |
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What happens with cancer cells in terms of checkpoints? |
Cancer cells have lost their checkpoints due to internal and external factors |
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What is meiosis? |
A special type of cell division that can produce sperm and egg cells (gametes) |
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What is meiosis? |
A special type of cell division that can produce sperm and egg cells (gametes) |
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What type of cells does meiosis produce? |
Non identical daughter cells |
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What is heredity? |
The transmission of traits from one generation to the next |
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What is heredity? |
The transmission of traits from one generation to the next |
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What is variation? |
Demonstrated by the differences in appearance that offspring show from parents and siblings |
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What is heredity? |
The transmission of traits from one generation to the next |
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What is variation? |
Demonstrated by the differences in appearance that offspring show from parents and siblings |
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What is genetics? |
The scientific study of heredity and variation |
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What is heredity? |
The transmission of traits from one generation to the next |
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What is variation? |
Demonstrated by the differences in appearance that offspring show from parents and siblings |
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What is genetics? |
The scientific study of heredity and variation |
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What are genes? |
The units of heredity and are made up of segments of DNA |
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What is heredity? |
The transmission of traits from one generation to the next |
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What is variation? |
Demonstrated by the differences in appearance that offspring show from parents and siblings |
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What is genetics? |
The scientific study of heredity and variation |
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What are genes? |
The units of heredity and are made up of segments of DNA |
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What is a locus/loci? |
A gene’s specific position along a chromosome |
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What do gametes do? |
Pass genes to the next generation |
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How do offspring acquire genes? |
By inheriting chromosomes. Most DNA is packaged in chromosomes |
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Human somatic cells have how many pairs of chromosomes? |
23 pairs. 46 total chromosomes |
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What is a karyotype? |
An ordered display of the pairs of chromosomes from a cell |
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What happens in asexual reproduction? |
A single individual passes all of its genes to its offspring without the fusion of gametes. |
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What is a clone? |
A group of genetically identical individuals from the same parent |
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What is a clone? |
A group of genetically identical individuals from the same parent |
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What happens in sexual reproduction? |
Two parents give rise to offspring that have unique combinations of genes inherited from the two parents |
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What are characteristics of somatic cells? |
Non reproductive cells Two sets of chromosomes Diploid |
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What are characteristics of somatic cells? |
Non reproductive cells Two sets of chromosomes Diploid |
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What are the characteristics of gametes? |
Reproductive cells, sperm and eggs Half as many chromosomes as somatic cells Haploid |
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How many chromosomes are in a gamete? |
A single pair Haploid number is n=23 |
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For each set of 23, how many autosomes and how many sex chromosomes exist? |
22 autosomes and 1 set of sex chromosomes |
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What is Aneuploidy? |
Abnormal number of chromosomes |
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What are the two chromosomes in each pair called? |
Homologous chromosomes/homologs |
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What are non sister chromatids? |
Chromatids in a homologous pair, one from each parents |
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How many chromosomes does a diploid cell (2n) have? |
Two sets of chromosomes. For humans, the diploid number is 46 |
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What is the life cycle? |
The generation to generation sequence of stages in the reproductive history of an organism |
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What is the life cycle? |
The generation to generation sequence of stages in the reproductive history of an organism |
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What is fertilization? what is the fertilized egg called? |
The union of gametes The fertilized egg is called a zygote. |
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What is the life cycle? |
The generation to generation sequence of stages in the reproductive history of an organism |
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What is fertilization? what is the fertilized egg called? |
The union of gametes The fertilized egg is called a zygote. |
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What are the only type of human cells produced by meiosis instead of mitosis? |
Gametes! |
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Why do fertilization and meiosis alternate in sexual life cycles? |
To maintain chromosome number |
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What are the only haploid cells in animals and how are they produced? |
Gametes are haploid. Produced by meiosis and undergo no further cell division before fertilization |
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What does meiosis do to the number of chromosomes? |
It reduces the number of chromosome sets from diploid 2n to haploid n |
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What do the two cell divisions in meiosis produce? |
It results in four daughter cells rather than the two daughter cells in mitosis |
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What two things occur in prophase 1? |
Synapsis and crossing over (Create chiasmata) |
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What happens at the metaphase plate? |
Homologous pairs line up at the metaphase plate |
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What is Meiosis 2? What is produced? |
Very similar to mitosis. During another round of cell division, the sister chromatids separate. This produces four haploid daughter cells |
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Summarize the products of mitosis |
Conserves the number of chromosome sets Produces cells that are genetically identical to the parent cell |
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Summarize the products of mitosis |
Conserves the number of chromosome sets Produces cells that are genetically identical to the parent cell |
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Summarize Meiosis |
Reduces the number of chromosome sets from diploid to haploid Produces cells that differ genetically from each other and from the parent cell |
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