Unit Test #2 Flashcards
What are linked genes?
Genes on the same chromosome.
What is the definition of a gene?
Sequence of DNA which codes for a specific protein.
Describe transcription.
Copies information from gene to a sequence of RNA.
Describe translation.
Converts RNA sequence to amino acid sequence
What is the definition of a genotype?
Actual sequence of DNA within an individual’s cell.
What is the definition of a phenotype?
The individual observable traits or characteristics.
Describe the way a mutation happen.
Wrong pairing of nitrogenous bases during DNA replication (or transcription)➡️different DNA strand➡️different mRNA strand➡️different codon➡️different amino acids➡️different amino acid sequence➡️different protein➡️different observable trait.
Explain the difference between homozygote and heterozygote alleles.
Homozygote: identical alleles
Heterozygote: different alleles
What is the difference between monohybrid and dihybrid?
Monohybrid: heterozygous for one gene
Dihybrid: heterozygous for 2 genes.
Explain the difference between domine and recessive allele. Explain homozygous dominant.
Dominant: Allele which is ALWAYS expressed ➡️ Capital Letters
Recessive:
Allele whose phenotype can be masked by a dominant allele ➡️ lowercase letter
Homozygous dominant: 2 dominant alleles.
What are the types of inheritance?
Allele effects:
-Complete dominance
-Multiple alleles
-Co-Dominance
-Incomplete Dominance
-Pleiotropy
Gene effects:
-Epistasis
-Multiple genes
-Environmental Interactions
-Multifactorial Interactions
Genes and Chromosomes:
-Linked Genes
-Sex Chromosomes
Explain the difference between incomplete dominance and co-dominance.
Incomplete: mix or blent
Co-Dominance: See phenotype separately.(blood)
What is the definition of multiple alleles?
A given gene may have more than two alleles.
Explain pleiotropy.
A single allele can have multiple effects, especially on distant and unrelated phenotypes
Explain epistasis.
Phenotypic expression of one gene is influenced by another gene
Explain polygenic inheritance.
It’s the result of combined effect of several genes.
What is the definition of natural selection? Give me some characteristics of it.
Differential contribution of offspring to the next generation by various genetic types belonging tot the same population.
Characteristics:
-Act on phenotype
-Act on individuals
-Variation MUST be heritable
What is the definition of evolution? Give me some characteristics of it.
A change in allele frequencies over time within a population.
Characteristics:
-Act on phenotype
-Act on individuals
Population evolves not individuals (change in allele frequencies over time)
What is the definition of the evolutionary fitness?
Genetic contribution that an organism makes to the next generation and to the generation thereafter.
It’s an actual quantity that can be measured or calculated.
Explain directional selection.
It favorises individuals that vary in one direction
Explain stabilizing selection.
It favorises individuals that have the average version of the trait.
Explain disruptive selection.
It favorises individuals that demonstrate either extreme version of the trait.
Explain sexual selection and its two types.
The sex that spend the most time on the offspring is more picky. It favorises traits that increase the chances of reproduction.
Intersexual selection: more attractive to opposite sex
Intrasexual: improve ability to compete for mates.
It leads to sexual dysmorphism and male/female differences.
Explain microevolution.
Allele frequency change over time→ easy to prove
Explain adaptation.
Evolution of adaptive trait.
Explain macroevolution and how to see it.
Large phenotypic changes.
Many many years:
-Fossils
-Extinction
-Transitional forms
What is the difference between a bottleneck and the founder effet.
Bottleneck: a lot of dying
Founder effect: start new population
Explain genetic drift.
Random changes in allele frequencies in a population due to random nature of sexual reproduction.
Explain speciation.
Process by which one species splits into two or more daughter species, often gradually.
Name species concept and describe them.
Morphological species:
-Look alike, but:
-Males and females don’t look alike
-Immature individuals may not look like parents
Biological species:
-Species are groups of actually or potentially interbreeding natural populations which are reproductively isolated form other such groups.
What are the modes of speciation?
Allopatric
Sympatric
Prezygotic
Postsygotic
Explain allopatric speciation.
Reproductive isolation and divergence often physical separation.
Explain sympatric speciation.
-Reproductive isolation and divergence while populations are not physically separated.
-Disruptive selection
-Sexual selection
Explain the different types of prezygotic selection.
1-Behavioral selection:
-Individuals reject or fail to recognize potential mating partners.
Habitat isolation:
2-Individuals mate in different locations.
3-Temporal isolation:
Mating periods don’t overlap.
4-Mechanical isolation:
Difference in sizes and shapes of reproductive organs.
5-Gametic isolation:
Eggs don’t have appropriate chemical signals for sperm or sperm unable to attach and to penetrate egg.
Explain the different types of postzygotic selection.
1-Low hybrid zygote viability:
Fail to mature or have severe abnormalities.
2-Low hybrid adult viability:
Lower survival rate
3-Hybrid infertility:
Offspring are healthy and viable, but infertile.
