Chapter 2: Chromosomes and Cells Flashcards
What is a Model Genetic Organism?
Organisms with characteristics that make them useful for genetic analysis
What are some common characteristics of Model Organism (6)
- Short generation time
- Production of numerous progeny
- The ability to carry out controlled genetic crosses
- The ability to be reared in a lab environment
- The availability of numerous genetic variants
- An accumulated body of knowledge about their genetic systems
What are the difference in Nucleus, Cell diameter, Genome, DNA, amount of DNA, and membrane-bound organelles with prokaryotes and eukaryotes?
What helps organize DNA molecules?
Histones form tightly packed chromosomes to help regulated accessibility and enable DNA to fit into nucleus
- Bacteria do not have histones
- Archaea have histones
Are viruses prokaryotic or eukaryotic?
Neither, viruses are not alive
What is the make up of a virus?
- Outer protein coat
- Inner nucleic acid
What does Haploid mean?
Cell that contains 1 copy of every chromosome
What does Diploid mean?
Cell that contains 2 copies of every chromosome
- How many chromosomes
- How many DNA molecules
- Diploid or Haploid
- 2 chromosomes
- 4 DNA molecules
- Haploid
- How many chromosomes
- How many DNA molecules
- Diploid or Haploid
- 2 chromosomes
- 2 DNA molecules
- Diploid
- How many chromosomes 2. How many DNA molecules 3. Diploid or Haploid
- 1 chromosome
- 1 DNA molecule
- Haploid
- How many chromosomes
- How many DNA molecules
- Diploid or Haploid
- 1 Chromosome
- 2 DNA molecules
- Haploid
What is Submetacentric, Metacentric, Telocentric, and Acrocentric
What is a karyotype?
Visual display of an individuals chromosome
What is a gene?
Genetic factor that helps determine a trait; DNA that leads to transcription of an RNA
how are homologous chromosomes related to alleles?
- Homologous chromosomes have same genes, but may have different forms of gene (alleles)
- We get one chromosome from mom and one from dad. These pairs of chromosomes are called homologous chromosomes
What are telomeres?
Specific DNA sequences and associated protein located at the tips of linear DNA
What is a centromere?
The centromere is a constricted region of the chromosome where the kinetochores form and the spindle microtubules attach
What are the eukaryotic cell cycles?
Interphase
- G1
- S
- G2
M phase
- M (mitosis)
- C (cytokinesis)
What occurs during the G1 phase?
Grows and proteins necessary for cell division are synthesized
What occurs during prophase of mitosis?
Chromosomes condense.
Each chromosome possesses two chromatids.
The mitotic spindle forms
What happens during prometaphase of mitosis
The nuclear membrane disintegrates.
Spindle microtubules attach to chromatids
What happens during Metaphase of mitosis?
Chromosomes line up on the metaphase plate
What happens during anaphase of mitosis
Separation
What molecule is cleaved in order for anaphase to occur?
Cohesin keep sister chromatids together, must be cleaved for anaphase to occur
What is shugoshin?
A protein that protects cohesin from cleave during anaphase I
What occurs during prophase of Meiosis I?
Synapsis is the connect of homologous chromosomes to form a tetrad and to allow crossing over.
Synapsis: Close pairing of homologous chromosomes
Tetrad: Closely associated four-sister chromatids of two homologous chromosomes
Crossing over: exchange of genetic info between non-sister chromatids
What is the synaptonemal complex?
A protein structure that forms between homologous chromosomes during meiosis and is thought to mediate synapsis and recombination
What is crossing over?
Takes place in prophase 1, refers to the exchange of genetic material between non-sister chromatids
What is independent assortment?
how different genes independently separate from one another
