Genetic Processes Flashcards
What is a somatic cell?
A plant or animal cell that forms the body of the organism; excludes reproductive cell
What are the three functions of cell division?
~growth of the organism
~repair of tissues and organs that have been damaged
~maintenance to replace dying or dead cells
How long does the cell cycle take?
For most healthy, actively dividing animal cells, the cell cycle takes about 12 to 24 hours
Which cells last the longest and shortest amount of time?
Stomach cells last a few hours and nerve cells last 60 years
What are the 6 stages of the cell cycle?
1) interphase
2) Prophase
3) Metaphase
4) Anaphase
5) Telephase
6) Cytokenisis
Phases 2 through 6 are Mitosis. It replicates DNA (nucleus) 5-10% of cells are in these phases.
What happens in Interphase?
Between 90-95% of cells are in interphase.
at the end of interphase it double its DNA
What happens in Prophase?
~nuclear membrane disappears/disintegrates, chromosomes are now free in the cytoplasm and are more susceptible to disease (i.e. cancer)
~chromatin shortens and thickens to become visible chromosomes
What happens in Metaphase?
chromosomes line up on the equator of the cell
What happens in Anaphase?
centromere splits, so each sister chromatid gets pulled to opposite poles of the cell
What happens in Telephase?
a nuclear membrane reappear (2–>1 for each pole) chromosomes become chromatin
What happens during cytokenisis?
Dividing cytoplasm with all organelles
- *in plants the rectangular cell indents in the middle (cell plate) in preparation for dividing**
- *in animals the circular shaped cell indents in the middle (cleavage furrow or “pinch”) to prepare for the cell dividing**
whats the analogy for DNA and protein?
DNA=cookbook/recipe
Protein= cookie
What is an Autosome?
a chromosome that is not involved in determining the sex of an organism
~Autosomes are chromosomes #1-22
what are sex chromosomes?
an X or Y chromosomes, which determines the genetic sex of an organism
the 23rd pair of chromosomes —> males: XY
–>females:XX
girls have 23 macthing pairs of chromosomes and boys have 22 matching pairs and an XY
What are homologous chromosomes?
they are pairs of chromosomes that appear similar, in terms of their length, centromere location, and banding pattern when stained with certain dyes. They contain the same sequence of genes as another chromosome.
homologous chromosomes are not identical
What is an allele?
a different form of the same gene.
~these different forms account for the differences in specific traits, such as brown hair versus blonde hair
~represented by letters, capitals are dominant and lower case are recessive
What is a gene?
a part of a chromosome that governs the expression of a trait and is passed on to offspring; it has a specific DNA sequence
What is a karyotype?
a photograph of pairs of homologous chromosomes in a cell
~take a blood sample; look for white blood cells during mitosis (metaphase) and take a picture of the chromosomes
~enlarge the photo, place it in a gel-like substance, then cut out all the chromosomes, pair them up and place them in order, and label them
~this checks genetic diseases and can tell gender of the body
What is a gamete?
a male or female reproductive cell
What is a zygote?
a cell formed by the fusion of two gametes
What is fertilization?
in humans, the joining of male and female haploid gametes
What is a haploid cell?
a cell that contains half the number of chromosomes as the parent cell (from the Greek word meaning single)
What is a diploid cell?
a cell that contains pairs of homologous chromosomes (from the Greek word meaning double)
What is meiosis?
the cellular process that produces cells containing half the number of chromosomes as the parent cell. The process that produces gametes with a haploid number of chromosmes