LT’s #1,2,3: quiz #1 Flashcards
Genetics
Study of heredity and variation of inherited characteristics
DNA
DNA stores the hereditary information in organisms. It is the information carrying molecule located in the nucleus of eukaryotic cells.
- long chain of nucleotide building blocks
- pair of nucleotide chains twist together to form double helix (A&T, G&C)
Chromatin
Term used to describe the genetic material during interphase. All of the DNA molecules and the associated proteins in the nucleus
Gene
Segment of DNA that encodes for a specific piece of information/trait (ie. gene for eye colour) Occupies specific location (locus or loci) on a chromosome
Diploid
Cells have 2 copies of each chromosome (2n)
ie. human somatic cells=46 chromosomes
Haploid
Cells have half the number of chromosomes (n)
ie. human gametes=23 chromosomes
Chromosomes
The individual coiled up molecules of DNA that contain thousands of genes. Found in nucleus of eukaryotic cells.
Homologous Chromosomes
Chromosomes that code for the same info (not genetically identical) Pair of chromosomes carrying different alleles of the same genes. (Matching pairs of chromosomes, similar in size and carrying the info for the same genes)
Chromatid
A single “arm” in a duplicated chromosome
Sister Chromatids
The two chromatids of a duplicated chromosome that are attached together at their centromere. Genetically identical
Cell Cycle
A continuous sequence of cell growth and division for all body (somatic) cells. Consists of three stages: 1) Interphase 2)Mitosis 3)Cytokinesis
For most of cell cycle DNA exists as chromatin
Interphase
The period between cell divisions. Cells undergo their normal activities of obtaining energy, synthesizing products and repairing damage.
The Three Stages of Interphase
1) G1 phase- “gap 1 phase” Cells carry out normal processes and prepare for S phase.
2) S phase- “synthesis phase” DNA is replicated for cell division. (chromatin replicate to form sister chromatids)
3) G2 phase- “gap 2 phase” Cells begin final preparations for cell division.
Mitosis
The process of cell division. Genetic material in nucleus divided equally into 2 new nuclei. There are 4 main stages (PMAT)
- occurs in somatic cells
- purpose of process is to grow, repair injured organisms, replace old+dead cells
- 1 cell division
- 2 cells produced that are genetically identical to parent cell
- 46 chromosomes in daughter cell (diploid number)
Prophase
- nuclear membrane dissolves
- preparing for division
- chromatins condense
Asexual Reproduction
Production of offspring from single parent; genetic makeup of offspring is identical to parent
ie. copperhead snake and starfish (can produce sexually or asexually)
Advantages of Asexual Reproduction
- no finding mate
- no specialized mating behaviours
- no specialized anatomy
- heredity direct and invariable
Sexual Reproduction
Production of offspring from fusion of 2 sex cells (usually from 2 different parents); genetic makeup of offspring is different from either parent (merging of 2 haploid gametes)
Advantages of Sexual Reproduction
Variable offspring and traits to adapt to change
Metaphase
-chromosomes line up in middle of cell
Anaphase
The chromatids are separated by the spindle fibres which are attached for eh centrioles and the new chromosomes are pulled to opposite sides of the cell.
Telophase
Nuclear membrane reforms. There are 2 nuclei. Chromatins begin to uncoil.
Cytokinesis
The division of the cytoplasm and organelles. Occurs after mitosis.
Cell Division
The mother cell divides into 2 identical daughter cells.