Exam 3: Questions Flashcards
What is non-coding DNA (such as intron) and what purpose might it serve?
Many regions of noncoding DNA play a role in the control of gene activity, meaning they help determine when and where certain genes are turned on or off. Other regions of noncoding DNA are important for protein assembly.
Describe the process of gene expression (transcription/translation), using appropriate terminology (RNA polymerase, mRNA/tRNA, codons, etc)
It consists of two major steps: transcription and translation. Together, transcription and translation are known as gene expression. During the process of transcription, the information stored in a gene’s DNA is passed to a similar molecule called RNA (ribonucleic acid) in the cell nucleus.
Discuss the causes and results of mutations (good, bad, neutral)
Many mutations are neutral and have no effect on the organism in which they occur. Some mutations are beneficial and improve fitness. An example is a mutation that confers antibiotic resistance in bacteria. Other mutations are harmful and decrease fitness, such as the mutations that cause genetic disorders
Explain what heredity is, discussing chromosome, genes and alleles, haploid and diploid
Germ line cells are haploid, which means they contain a single set of chromosomes. In diploid cells, one set of chromosomes is inherited from the individual’s mother, while the second is inherited from the father. Humans have 46 chromosomes in each diploid cell.
What do Mendel’s principles of segregation and independent assortment mean?
The law of segregation states that every individual possesses two alleles and only one allele is passed on to the offspring. The law of independent assortment states that the inheritance of one pair of genes is independent of inheritance of another pair.
How would you identify a trait as dominant or recessive? How does incomplete dominance differ from complete dominance? From co-dominance?
Codominance and Incomplete dominance are two types of genetic inheritance. Codominance essentially means that no allele can block or mask the expression of the other allele. On the other hand, incomplete dominance is a condition in which a dominant allele does not completely mask the effects of a recessive allele. Read on to explore more differences between the two.
Explain the difference between genotype and phenotype. Can environemnt impact phenotype?
An organism’s phenotype is all of its observable characteristics — which are influenced both by its genotype and by the environment. The phenotype is the visible or expressed trait, such as hair color.
What is pleiotropy? Polygenic inheritance
Pleiotropy is defined as the regulation of numerous characteristics by a single gene. The regulation of several characteristics by a single gene is referred to as phylogenetic inheritance.
How is inheritance of a sex linked trait different from an autosomal trait?
Sex-linked inheritance occurs via the genes located on sex chromosomes (X and Y chromosomes) while autosomal inheritance occurs via the genes located on autosomes.
Can you establish genotype from pedigree or phenotypic information?
Can you complete a monohybrid or dihybrid cross to estimate genotype and phenotype ratios of offspring in either F1 and F2 generation?
Monohybrid cross the F1 generation is all heterozygous while the F2 is a combination of homozygous and heterozygous offspring.
What is the difinition of evolution? Why is it not that species improve over large span of time?
Biological evolution refers to the cumulative changes that occur in a population over time. These changes are produced at the genetic level as organisms
List and briefly describe the three random mechanism of evolution
Natural selection is considered the main mechanism that causes populations to evolve. However, there are several other mechanisms of evolution, including mutation, genetic drift, and gene flow.
What is the natural selection? What are the three requirement for natural selection?
The essence of Darwin’s theory is that natural selection will occur if three conditions are met. These conditions, highlighted in bold above, are a struggle for existence, variation and inheritance. These are said to be the necessary and sufficient conditions for natural selection to occur.
How are directional, stabilizing, disruptive, and sexual selection different? How are they similar?
Stabilizing, directional, and diversifying selection either decrease, shift, or increase the genetic variance of a population.
