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the particular genetic makeup of an individual
The visable measureable features of an individual
a single, large DNA molecule wrapped around proteins (histones); located in the nuclei of most eukaryotic cells
- one of the two identical DNA molecules that make up a duplicated chromosome following DNA replication
- connected at a region of the chromosome known as the centromere
- Same gene different alleles
- The two copies of each chromosome in a diploid cell. one chromosome in the pair is inherited from the mother, the other is inherited from the father
How are the X and Y chromosomes different from homologous chromosomes?
Genes located on the X and Y chromosome in males do not have a second copy
What are alleles?
Alternative versions of the same gene that have different nucleotide sequences
- having two copies of every chromosome
- sex cells or gametes
- Having only one copy of every chromosome
- somatic cells (non-reproductive cells)
paired chromosomes present in both males and females; all chromosomes except the X and Y chromosomes
- Paired chromosomes that differ between male and female
- XX= Female
- XY= Male
In humans, does the male or female determine the sex of the child?
Having two different alleles of a given gene
Having two identical alleles of the same gene
An allele that can mask the presence of a recessive allele
an allele that reveals itself itself in the phenotype only if the organism has two copies of that allele
What is the genotype of a person who is heterozygous dominant?
***What are the two major sources by which genetic variation is introduced into offspring?
- -chromosomes passed down
- Homologousmaternal and paternal chromosomes pair up and swap genetic information. Maternal chromosomes actually contain segments from paternal chromosomes and vice versa
- Meiosis I
- Alleles of different genes are distributed independently of one another, not as a package. A unique combination of maternal and paternal chromosomes is distributed into each sperm and each egg.
- Meiosis II
Describe the 3D structure of DNA.
- two strands of linked nucleotides are bound together and twisted around each other to form a spiral-shapped double helix
- the sugars and phosphates = backbone
- bases = rungs
Where is DNA found in a cell?
inside the nucleus in the form of chromosomes
What are the componets of chromosomes?
DNA and protein (histones)
What holds the sugar and phosphate groups together?
What holds the bases together?
What are the three componets of a nucleotide?
a sugar, a phosphate and a base
Describe the assembly of the nucleotide into the 3D structure of DNA.
- the outside is phosphate groups and sugars alternating
- the middle is A,T,C,G held together by hydrogen bonds attached to a sugar
Describe the process of DNA replication.
- 1. the helix unwinds and the two strands unzip
- 2. DNA polymerase pairs new nucleotides to each individual DNA strand matich A with T and C with G.
- 3. The end result is 2 molecules of DNA
What enzyme is involved in DNA replication?
Is there any difference in the DNA found in different cells of the human body?
No, just different parts of the DNA are being read
What is PCR?
- Polymerase Chain Reaction
- a laboratory technique used to replicate, and thus ampify, a specific DNA segment
Describe the steps of PCR.
- 1. Heating- separates DNA strands
- 2. Cooling- Allows DNA polymerase to pair new nucleotides with the original template strand
What are the "ingredients" required for PCR?
- -Nucleotides A,T,C,G
- -DNA polymerase
Describe the stpes in running a gel.
- 1. Collect cells and extract DNA from the crime scene evidence.
- 2. PCR amplify multiple STR regions
- 3. Separate STR's using gel electrophoresis
Why does DNA move through the gel?
because it has a negative charge, and therefore it moves towards the positive end of the gel.
Sequences of DNA that serve as instructions for making proteins
DNA sequences that do not hold instructions to make protein
Are coding or non-coding regions more variable?
Non-coding sequences vary much more between individuals
Which region is used in making DNA fingerprints?
STR (Short Tandem Repeat) Regions
How many chromosomes are found in haploid cells?
How many chromosomes are found in diploid cells?
A type of asexual reproduction in which one parental cell divides into two
a group of organisms of the same species living together in the same geographic area
Chance in allele frequencies in a population over time
The relative ability of an organism to survive and reproduce in a particular environment
Differential survival and reproduction of individuals in response to environmental pressure that leads to chance in allele frequencies in a population over time
The response of a population to environmental pressure, so that advantageous traits become more common in the population over time
Occurs when a single phenotype predominates in a paticular environment
occurs when phenotypes at each end of the spectrum are less suited to the environment than organisms in the middle of the phenotypic range
Tupically occurs in a "patchy" environment, in which extremes of the phenotypic range do better than middle range individuals