Final Flashcards
Who discovered meiosis?
Gregor Mendel
What is an allele?
Alternate versions of a gene
What is a genotype?
The actual makeup of a gene (Gg, Yy, Ss)
What is a phenotype?
Observable traits (Hair color, eye color)
What is the principle of segregation?
The idea that each parent has equal opportunities of passing down either allele they have
Incomplete Dominance?
Neither allele is fully expressed
Codominance
Both alleles are expressed (speckled colors, blood types)
Polygenic inheritance
Phenotypes all working at once (height, eye color, skin color)
Sex-linked genes
Genes that are carried on the x or y chromosomes
What is epistasis?
One’s gene expressions masking another gene (baldness, widow’s peak)
Phenylketonuria (PKU)
Disease allele where it cannot make the enzyme to break down phenylalanine and causes toxic by-products. Avoid phenylalanine in the environment
Semiconservative
Each daughter DNA helix contains 1 complete template strand and 1 completely new strand
Conservative
Of 2 daughter DNA helicases, 1 is new and 1 is old
Disperse
Each daughter DNA molecules contains strands that are a mix of old and new DNA
DNA polymerase
Many types of polymerases, but all build DNA by connecting nucleotides
Prior to DNA polymerase
- Helicase opens double helix
- Single-stranded DNA binding proteins stabilize
- Topoisomerase relieves twisting strain
Primase
Makes an RNA primer as a starting point, since DNA polymerase cannot start from scratch
Lagging strand vs. leading strand
The leading strand continuously replicates towards the fork, lagging strand replicates away from the fork. The lagging strand is always shorter than the leading strand
Telomere
Located at the end of the chromosomes
Telomerase
An enzyme present in some cells that re-lengthen the telomere so more cell division can occur
Non-coding DNA
Can be in between coding or in the middle of a sequence, has functions but not as important
Transcription
Happens before translation. Turns a DNA sequence into a complementary RNA sequence in the nucleus.
Translation
Turns RNA sequences into a sequence of amino acids in order to create proteins. In cytoplasm and uses ribosomes.
mRNA (messenger)
The first step, a sequence of RNA that carries information specifying a certain amino acid sequence
rRNA (ribosomal)
Second step, RNA that forms part of the ribosomes that are made of RNA and proteins
tRNA (transfer)
RNA that binds to the mRNA on one end and an amino acid on the other end, the link between mRNA and amino acids
Codon
3 bases of RNA that code for an amino acid (AUG)
Mutations
Permanent alterations to DNA
Mismatch Repairs
Work to reduce mistakes in DNA replication
What are mutations
The raw material of evolution
Point Mutations
Affect one or a small number of base pairs
Silent mutations
Substitution that leads to a codon coding for the same amino acid, mostly on the 3rd base of a codon
Missense mutation
Usually just on one amino acid, but can have a great affect
What are the three steps of transcription and translation?
- initiation 2. elongation 3. termination
Describe protein synthesis briefly
- RNA polymerase connects RNA bases to DNA, making mRNA
- mRNA editing often to make the message
- Leaves the nucleus in eukaryotic cells
- Moves onto rRNA to translation
- tRNA brings amino acids together to create proteins
What speeds up protein synthesis?
Ribosomes being able to translate an mRNA at the same time
Introns
Non-coding DNA that gets removed