Test III- Ch. 9 Beyong Mendal Flashcards
Incomplete dominance and co-dominance
When a heterozygous individual inherits 2 dominant alleles, they both get expressed.
ex. Red flower + white flower = pink flower
Multiple alleles
Most genes occur in more than 2 forms
ex. Blood type
Pleiotropy
a single gene determines or influences more than 1 characteristic.
ex. sickle cell results in multiple effects
polygenic inheritance
multiple genes contribute to a single trait
ex. skin color, average height
sex linked traits
located on the X or Y chromosome and are inherited differently by males and females
autosome
non-sex linked chromosome
proteins
- composed of folded chains of amino acids
- Shape specific- function is directly related to form
Nucleic acids
DNA- double helix of nucleotides
RNA-single strand of nucleotides
Nitrogenous bases found in DNA
Adenine ——– Thymine
Guanine——–Cytosine
DNA replication
- DNA strand is “unzipped” by DNA polymerase (an enzyme)
2. Free bases attach to the strand following the base pair rule
What nitrogenous bases are used in RNA
Adenine ——– Uracil
Guanine——— Cytosine
Protein synthesis
- Gene
- RNA
- Protein
Gene role in Protein synthesis
-a specific segment of a DNA molecule which “codes” for synthesizing of one RNA molecule
Types of RNA and their functions
Coding RNA -mRNA- "messenger" Noncoding -rRNA- "ribosomal" -tRNA- "transfer"
2 steps of Protein Synthesis
- Transcription (in nucleus)
2. Translation (in cytoplasm)
Transcription 3 steps
Initiation
Elongation
Termination
Initiation (Transcription)
1st step of Transcription
-RNA polymerase attaches to the DNA at the promoter
promoter DNA
Length along the DNA strand where RNA polymerase attaches to the DNA to begin Transcription
Elongation (Transcription)
2nd stage of Transcription
-RNA polymerase grows the RNA strand using the DNA as a template.
Termination (Transcription)
3rd stage of Transcription
-Transcription stops when the RNA polymerase reaches a terminator
Terminator DNA
strand of Dna that signals an end to Transcription
RNA splicing
- Occurs in Eukaryotes
- mRNA is fitted with a cap and tail
- the introns are removed and the exons are spliced together
Intron
Sniped out of the RNA as unnecessary junk between Transcription and Translation
Exons
Expressed bits of RNA that are kept for Translation
Translation important structures
mRNA
rRNA
tRNA
mRNA
- Messenger
- Carries the specific nucleotide sequence of the gene in triplets called codons
rRNA
“Ribosomal”
-The ribosome is primarily composed of rRNA
tRNA
“transfer”
- Has the ability to transport amino acids
- Contains an anticodon
3 steps of Translation
Initiation
Elongation
Termination
Initiation (Translation)
1st step of Translation
The small and large subunit of the ribosome bind around a start codon.
-Start Codon- AUG
Elongation (Translation)
Elongation 2nd step of Translation
- Codon Recognition
- Peptide bond Formation
- Translocation
Peptide bond Formation
State of Translation Elongation
because the tRNA is bound to an amino acid, the ribosome can now form a peptide bond between amino acids.
Translocation
Stage of Translation Elongation
-the tRNA in the A site is removed; the tRNA in the P site moves over
Termination (translation)
3rd Stage of Translation
-the ribosomes stop when it reaches a “stop codon”
2 Steps of Protein Synthesis
- Transcription (in nucleus)
- Translation (in cytoplasm)
Mutations
- Random changes in DNA
- Most come fro copy errors
