Semester 2 Biology Flashcards
Heterozygous
When the alleles from each parent are different
Dominant
Allele that covers up the recessive allele
Recessive
Allele that gets covered up by the dominant. (Lower case).
Gamete
Egg and sperm
Zygote
First cell formed after fertilization
Karyotype
Chromosomes removed from a dividing cell. Placed in a chart according to size with their homologous partner. Helps determine gender and genetic disorders.
Genotype
A list of alleles for possible offspring
Phenotype
List of appearances for possible offspring. Physical traits.
Probability
The likelihood that a particular event will occur
Law/principle of independent assortment
Genes for different traits can segregate independently during the formation of genes.
Principle of segregation
Each gamete carries only one allele for each gene.
Mendel
Founded genetics
Gene
A piece of DNA
Trait
A specific characteristic for an individual
Carrier
Someone who has the gene for a trait, but doesn’t express/ show it
P1 generation
The first generation
F1 generation
Second generation
F2 generation
Third generation
Test cross
A individual of unknown genotype is crossed with a homozygous recessive individual
Mono hybrid cross
A cross between individuals that uses one trait
Co dominance
Both alleles are dominant and fight for expression
Incomplete dominance
Neither allele is completely dominant. (Blending).
Sex determination
A punnet square using x and y can be used to find probability that kid will be a boy or girl. There is a 50 50 chance.
Dihybrid cross
Any cross involving two traits at a time. Use 16 squares.
Chromosome
Genetic info bundled into packages of dna
Chromatid
One of the two identical parts of a duplicated chromosome.
Centromere
Where the two sister chromatids meet and are held together.
Genetic linkage
Tendency for alleles on one chromosome to be inherited to the other due to meiosis.
Homozygous
Both alleles are the same letter and case
Pedigrees
A family tree that can be used to determine sex-linked traits of offspring
Locus
The location of a gene on a chromosome
Differences between DNA and ran
DNA is a long polymer with a phosphate and deoxyribose backbone. It has four different nitrogenous bases, adenine thymine cytosine and guanine. RNA has a ribose and phosphate backbone. It’s four bases are adenine guanine cytosine uracil. RNA1 chain DNA 2 chains
Ribose
Backbone of RNA
Deoxyribose
Backbone of DNA
Purines
2 carbon rings (a,g)
Pyrimadines
1 carbon ring (t,c)
Nucleotides
Building block of DNA. Includes 1 phosphate, 1 deoxyribose, and 1 nitrogenous base.
Mutation
Heritable changes in genetic information. Good bad lethal or neutral. Frame shift: add or delete a nucleotide. Point: one nucleotide is switched.
Hydrogen bonds
Weak. Between a and t are two hydrogen bonds. Between g and c are three hydrogen bonds
Covalent bonds
Strong. Holds backbone together
DNA replication
During the s of interphase, the DNA doubles using enzymes
Helicase
Unzips hydrogen bonds. Breaks into two strands
DNA polymerase
Deals out the correct nucleotides to the old strands of DNA, creating two new identical strands
Replication fork
When the DNA separates it takes in the appearance of a fork
Repair enzymes
Proofread and fix mutations
Promoter
Marks the beginning of a gene.
Termination signal
Where transcription stops. Marks the end of a gene.
Transcription
The process of copying instructions from DNA to mRNA
Translation
The process of decoding the mRNA into a protein
Codon
Any three mRNA nucleotide sequences that code for an amino acid
Anticodon
A three nucleotide sequence on tRNA. The exact opposite of mRNA codon
Start codon
AUG. Codes for the AA met. All polypeptides start with met
Stop codon
UAA, UAG, UGA. No AA match these sequences
MRNA
Messenger RNA. copies and transports instructions from the DNA to the ribosome. AKA: transcript
tRNA
Transfer RNA. Decodes the instructions and builds the protein. Transfers amino acids
rRNA
Ribosomal RNA. Location of protein synthesis. 2 put together = 1 ribosome. Is the most abundant organelle
Steps of protein synthesis. Steps of transcription
RNA polymerase binds to the promoter and relaxes DNA. RNA polymerase moves to the first nucleotide of the template chain. A complimentary mRNA chain is built using A,G,C,U. RNA polymerase teaches the termination signal and pops off to be recycled. MRNA transcript gets processed. DNA returns to normal.
Steps of translation
The process of decoding the mRNA into a protein. Ribosome attaches to the mRNA strand. tRNA with its anticodon and appropriate AA, attaches to the codon of the mRNA chain within the ribosome. Only two tRNA’s can fit into the ribosome at a time. Two AA’s bind together with peptide bonds. tRNA pops off to be recycled. This continues until the whole mRNA sequence is read.