Genetic Control of Function and Inheritance

Question 1

Transcription

Answer 1

• rewriting in the same language
• Genes as nucleic acid chains in DNA double helixes within nucleus.
• Transcribed into nucleic acids in the form of messenger (m)RNA.
• Need to transcribe it into an RNA that can leave the nucleus and then this can be read and translated in the cytoplasm in order to form the amino acid chain of a protein
• DNA strand unzipped by helicase enzymes
• One of two strands serves as template (or sense strand, and the other is the nonsense strand which is the complementary strand)

Question 2

Translation

Answer 2

• rewriting in different language
• Synthesis of protein chains from mRNA instructions.
• Going from nucleic acids to amino acids
• Final mRNA sequence an exact copy of DNA template without introns
• Therefore, it is an exact copy of JUST the exons –> Exons = EXPRESSED portion of DNA
• Ribosomal RNA on ribosome participates in the assembly of amino acids from mRNA code

Question 3

gene structure

Answer 3

• Double helix of nucleic acid chains (nucleotides).
• Individual character by presence of one of 4 nitrogenous bases.
• Purines (adenine & guanine) contain 2 nitrogen rings, pyrimidines (thymine & cytosine) contain 1.
• A-T
• G-C
• One purine binds to one pyrimidine

Question 4

how is RNA different than DNA

Answer 4

• Single stranded, more vulnerable
• Ribose sugar instead of deoxyribose
• Thymine replaced by uracil (T –> U)

Question 5

gene expression

Answer 5

• Refers to activity of genes
• Induction refers to processes increasing expression, as by an exogenous agent
• Repression is prevention of expression
• Operons control expression as promoter sites and structural genes

Question 6

mutation

Answer 6

• An accident of DNA duplication process
• Only mutations of germ cell DNA can be heritable
• Many somatic mutations fatal to embryo
• There are failures that are more minor that don’t cause demise of the embryo and are more common than the catastrophic failures

Question 7

chromosomes

Answer 7

• 23 pairs of matched DNA strands, one from each parent

- Wrapped up and coiled on histones to form chromatin within the chromosome

Question 8

meiosis vs mitosis

Answer 8

• Meiosis –> process of cloning (the way somatic tissues grow - gives off four daughter cells)
• Mitosis –> gives us germ cells

Question 9

genotype vs phenotype

Answer 9

• Genotype – gene structure
• Phenotype – gene expression, recognizable traits
• Phenotypes are specific but may have more than one genotype associated with it
• Therefore, carriers of genetic mutations may not all express their traits to the same degree

Question 10

penetrance

Answer 10

• ability of gene to express itself
• Most human traits and diseases exhibit polygenic inheritance (not as simple as mendelian genetics with the peas and the flowers

Question 11

complimentary genes

Answer 11

each gene mutually dependent on the other

Question 12

collaborative genes

Answer 12

two genes together produce phenotype neither would produce alone

Question 13

genomic imprinting

Answer 13

• Phenomenon in which one parental genome exhibits more influence over offspring than the other
• Ovarian teratomas of maternal while hydatidiform moles of paternal lineage

Question 14

linkage

Answer 14

• Genes residing in proximity to each other on a chromosome will tend to travel together without being split by crossing over events
• Ex: Color blindness with hemophilia A

Question 15

top 10 genetic disorders

Answer 15

• Familial combined hyperlipidemia
• Familial hypercholesterolemia
• Dominant otosclerosis
• Adult polycystic kidney disease
• Multiple exostoses
• Huntington’s disease
• Fragile X-syndrome
• Neurofibromatosis
• Cystic fibrosis (MC heritable disorder in Caucasians)
• Duchenne muscular dystrophy