Genetics midterm 1
the levels of organization
1. atoms
2.molecules
3. cells
4. tissue
5. organs
6.organ systems
7.organism
gameates
are haploid
contain one copy of each autosome and one sex chromosone
diploid cells
23 pairs of homologous chromosones, 22 pairs of non sex, 1 pair of sex chromosones
autosomes
non sex chromosones
sex chromosones
sex chromosones
human life cycle
1. formation of gameates (sperm or egg cells)
2. fertilization (diploid zygote)
3. Mitosis and development (germinal stage, embryonic development)
4. development of multicellular organism
DNA
consists of four nucleotide bases
1. Adenine
2.thymine
3. cytosine
4. guanine
carries genetic information depending on sequence
phenotype
the individual and its apperance/ traits/ and characteristics
proteins
chains of amino acids
transcription
information is transferred from DNA to an RNA molecule
translation
information is transferred from RNA to a protein through a code that specifies the amino acid sequence
DNA replication
information is transferred from one DNA molecule to another
ribsomes
cellular machinery that make proteins, which are located in the cytoplasm
DNA Polymerase
DNA to DNA; replication
RNA polymerase
DNA to RNA; transcription
strands of DNA
coding strand- carries the gene that encodes the protein of interest, carries the genetic code.
template strand-the complimenytary strand of the coding strand
RNA
transcribed as a single stranded molecule, contains the nucleotide uracil anstead of thymine, contains the sugar ribose, processed by the cell so its mature, unstable; degrades easily
coding region
the stretch of DNA that occurs between a start codon and a stop codon which can be potentially translated into a protein
promoter region
determines when and how often transcription occurs
core promoter
located in between the regulatory region and the protein coding region. RNA polymerase binds to a specific region of DNA called the core promoter
things found in the regulatory region
activators- activates transcription
repressors- inhibits transcription
genetic variation
is a result of changes to the DNA of an organism. it contributes to continuous development of the organism/ species. this results in phenotyoic changes
mutations
changes to DNA sequence; typically random
gene flow
organism moves from one population to another; carries genes from one population to another
sexual reproduction
gene shuffling
Natural selection
a natural gradual porocess that exists throughout all species. selection of genetic variation that imparts in adavantage to that specific environment. elimination of unfavourable genetic variations from the p[opulation
artificial selection
known as selective breeding. Humans, plants and animals have desirable traits and phenotypes so we breed them together on purpose
inherited mutations
somatic vs germaline (sex cell) mutations
spontaneous mutations
DNA replication errors
DNA polymerase and proof reading activity
induced mutations
casued by a mutagen like radiation, cigerette smoke, viruses etc
macro scale mutations
chromosomal mutations and aberrations.
-deletions
-duplications
-inversions
-insertions
-transloaction
micro scale mutations
point mutations, frameshift mutations
silent mutation
DNA change results in a new mRNA codon that specifies the same amino acid
missense mutation
DNA change results in a new mRNA codon that specifies a different amino acid
nonsense mutation
DNA change results in a new mRNA codon that is a STOP codon
Frameshift mutations
insertion or deletion of nucleotides into a gene to alter the reading frame of the gene
genes
eaxh gene has a specific position within a chromosone, two loci per gene; one gene per chromosone
alleles
different versions of the same gene in nature. For exanple blue and brown eyes
homozygous
an organism with twi identical copies of an alelle (AA or aa)
heterozygous
an organsim with two non-identical copies of an allele (Aa)
dominant allele
express phenotypes in heterozygous and homozygous genotypes
recessive allele
only express its phenotype in homozygous genotypes (aa)
punnent square
analyze single gene inheritance patterns and determine probability of offspring genotypes
null/amorphic alleles
a non functional protein is produced or no protein is produced
hypomorphic alleles
a poorly functioning protein is produced or a reduced amounts of a normally functioning protein is produced
recessive inheritance: normal phenotype
normal phenotype which produces lots of functional protein. unaffected off spring no disease
normal phenotype
phenotype produces adequate amounts of functional protein; no disease
recessive inheritance: affected phenotype
phenotype produces no functional proteins; affected/diseased
affected genotype
child with disease. Two normal (heterozygous) parents create a homozygous affected child
afffected (PKU) genotypes
two parents that are carriers give each a defective allele to create a child with disease
pedigree
consists of generations of genes and offsprings etc