BLD 430 EXAM QUESTIONS AND CORRECT ANSWERS
Mendelian genetics - answer As genes are passed down from parent to child, generation
to generation, they can move around on the chromosome and allow for there to be new
combinations of genes and traits that havent been seen before.
Law of segregation - answer A person has 2 genes for each trait, one from the mother
and one from the father. During gamete formation, the genes can separate and then
when fertilization occurs the individual will receive 1 trait when the genes unite.
Law of independent assortment - answer each gene pair segregates independently, all
possible combinations of genes can occur in gametes if genes are linked.
Locus - answer Specific spot on each chromosome where they can have different forms
of the same gene
Polymorphism - answer -When there are 2 or more alleles that are located at a single
locus, or any difference in DNA sequence among individuals.
-Generally thought to be a mutation but it does not have a huge effect on phenotype.
-This change that can occur in DNA sequence occurs in 1-2% of a population.
Uniparental disomy/monosomy: - answer -Disomy refers to when an individual receives
both chromosomes from 1 parent.
-Monosomy refers to when there is only ONE chromosome, and there is one missing.
Penetrance - answer If a mutation occurs for a disease in a gene, this is the probability
that a specific gene will actually be expressed phenotypically, or will show up as a
physical characteristic of the individual.
Multigenic - answer A trait that is present due to different genes combining and forming
new patterns. (skin color, eye color, height)
Epistasis - answer A gene interaction in which a pair of recessive genes at one locus
prevents expression of a dominant allele at another locus
Genotype vs phenotype - answer Genotype: the genetic makeup of an organism
Phenotype: The expressed physical traits of an organism
long and short arms of chromosomes - answer The short arm: "p"
long arm q.
Autosomal dominant - answer Autosomal Dominant: This means that the child of a
parent will receive the trait if one or both of the chromosomes are mutated. In many
,cases this means that a child will develop the disease even if only one chromosome is
affected.
-affected individuals are not sex realted and they are spread in every generation
Autosomal recessive - answer For the child to develop a disease or a trait, there must be
two abnormal forms or mutations of a gene, each one passed down from each parent.
-Only in homozygous individuals, inbreeding
Sex-linked: - answer This means that the trait or mutation is carried by one of the sex
chromosome, either X or Y. Most sex linked mutations are carried on the X chromosome
and there are very few carried on the Y.
-affected individuals are males and the mutant gene is carried by the female
-male
-female
-Affected individuals
-heterozygous for autosomal recessive
-carrier of sex linked recessive
-Death - answer -Square
-circle
-shaded
-half shaded
-bullseye
-slash
Consagunity - answer This means that two individuals that are related in some way
breed and have offspring.
Sexual vs asexual organisms recombination - answer -For sexually: crossing over
occurs during meiosis, DNA pieces are swapped between chromosomes.
-random assortment occurs, chromsomes randomly placed in different gametes
-merging of gametes from each parent
-As for asexual reproduction, the steps for recombination are conjugation, transduction
and transformation.
Linkage - answer This basically means that two genes are associated together and are
,passed down between generations together. So if the genes for red hair and blue eyes
were linked these phenotypes would always be seen together.
Linkage disequilibrium - answer -Nonrandom association of alleles at linked loci.
-Diminish through time due to recombination
LOD score
-affected by - answer tests to see if genes will be linked and inherited together.
-greater than 3 than the loci are linked, less than -2 means they are not linked.
Affected by:
-Penetrance, this is the probability that a gene will actually have any phenotypic
expression
-Males and females have different recombination frequencies
-It can be uncertain what the mode of inheritance is
Normal distribution - answer Normal distribution is a statistical term that is used to
represent many random variables as a bell shaped curve.
Hardy Weinberg assumptions - answer -Random mating
-No mutations
-No gene flow
-No natural selection
-large population size.
-no migration
Human Genome
-within which chromosomes - answer all of the genes are genetic information found in a
person within their nuclear and mitochondria chromosomes.
Homologues: - answer Carry matching genetic information, one from the mother and
one from the father
Allele - answer The alternate forms of a gene on homologous chromosomes
Homozygous vs heterozygous - answer Homozygous: two alleles that are the same
Heterozygous: two alleles that are different. An organism with two different alleles for a
single trait is said to be heterozygous for that trait.
, Chromatin and chromsome - answer -Chromatin is made up of DNA and proteins that is
condensed onto nucleosomes.
-Once the chromatin continues to to get condensed and packed even more it will
become chromosome.
Differentiate heterochromatin from euchromatin - answer -Heterochromatin is
chromatin is very tightly packed and not easily accessible.
-Euchromatin: open and actively involved in gene expression (transcription)?
Nucleosome composition - answer -146 base pairs of DNA that wraps and makes 1.65
negative superhelical turns around the octamer
-The octamer has 8 histone proteins,
2(H2a), 2(H2b), 2(H3), 2(H4)
-. A nucleosome looks like a bead like structure that is divided up into units by a double
helix that is not wound or linker regions.
Gene - answer -a region of DNA producing a polypeptide or a functional RNA molecuel
-The fundamental physical and functional unit of inheritance that encodes a functional
product is
Exons vs introns - answer Exons are the coding regions that actually code for a
something (usually proteins) and can be transcribed. Introns are spliced out if the gene
because they dont code for anything.
Nucleic acids vs nucleotides - answer -Nucleic Acids are the basic unit of DNA and RNA
and they are made up of nucleotides.
-Nucleotides are bound together through the bond between their phosphate and
hydroxyl groups located on their sugars.
Nucleotide composition - answer Nucleotides are made up of a nitrogenous base, a
Mendelian genetics - answer As genes are passed down from parent to child, generation
to generation, they can move around on the chromosome and allow for there to be new
combinations of genes and traits that havent been seen before.
Law of segregation - answer A person has 2 genes for each trait, one from the mother
and one from the father. During gamete formation, the genes can separate and then
when fertilization occurs the individual will receive 1 trait when the genes unite.
Law of independent assortment - answer each gene pair segregates independently, all
possible combinations of genes can occur in gametes if genes are linked.
Locus - answer Specific spot on each chromosome where they can have different forms
of the same gene
Polymorphism - answer -When there are 2 or more alleles that are located at a single
locus, or any difference in DNA sequence among individuals.
-Generally thought to be a mutation but it does not have a huge effect on phenotype.
-This change that can occur in DNA sequence occurs in 1-2% of a population.
Uniparental disomy/monosomy: - answer -Disomy refers to when an individual receives
both chromosomes from 1 parent.
-Monosomy refers to when there is only ONE chromosome, and there is one missing.
Penetrance - answer If a mutation occurs for a disease in a gene, this is the probability
that a specific gene will actually be expressed phenotypically, or will show up as a
physical characteristic of the individual.
Multigenic - answer A trait that is present due to different genes combining and forming
new patterns. (skin color, eye color, height)
Epistasis - answer A gene interaction in which a pair of recessive genes at one locus
prevents expression of a dominant allele at another locus
Genotype vs phenotype - answer Genotype: the genetic makeup of an organism
Phenotype: The expressed physical traits of an organism
long and short arms of chromosomes - answer The short arm: "p"
long arm q.
Autosomal dominant - answer Autosomal Dominant: This means that the child of a
parent will receive the trait if one or both of the chromosomes are mutated. In many
,cases this means that a child will develop the disease even if only one chromosome is
affected.
-affected individuals are not sex realted and they are spread in every generation
Autosomal recessive - answer For the child to develop a disease or a trait, there must be
two abnormal forms or mutations of a gene, each one passed down from each parent.
-Only in homozygous individuals, inbreeding
Sex-linked: - answer This means that the trait or mutation is carried by one of the sex
chromosome, either X or Y. Most sex linked mutations are carried on the X chromosome
and there are very few carried on the Y.
-affected individuals are males and the mutant gene is carried by the female
-male
-female
-Affected individuals
-heterozygous for autosomal recessive
-carrier of sex linked recessive
-Death - answer -Square
-circle
-shaded
-half shaded
-bullseye
-slash
Consagunity - answer This means that two individuals that are related in some way
breed and have offspring.
Sexual vs asexual organisms recombination - answer -For sexually: crossing over
occurs during meiosis, DNA pieces are swapped between chromosomes.
-random assortment occurs, chromsomes randomly placed in different gametes
-merging of gametes from each parent
-As for asexual reproduction, the steps for recombination are conjugation, transduction
and transformation.
Linkage - answer This basically means that two genes are associated together and are
,passed down between generations together. So if the genes for red hair and blue eyes
were linked these phenotypes would always be seen together.
Linkage disequilibrium - answer -Nonrandom association of alleles at linked loci.
-Diminish through time due to recombination
LOD score
-affected by - answer tests to see if genes will be linked and inherited together.
-greater than 3 than the loci are linked, less than -2 means they are not linked.
Affected by:
-Penetrance, this is the probability that a gene will actually have any phenotypic
expression
-Males and females have different recombination frequencies
-It can be uncertain what the mode of inheritance is
Normal distribution - answer Normal distribution is a statistical term that is used to
represent many random variables as a bell shaped curve.
Hardy Weinberg assumptions - answer -Random mating
-No mutations
-No gene flow
-No natural selection
-large population size.
-no migration
Human Genome
-within which chromosomes - answer all of the genes are genetic information found in a
person within their nuclear and mitochondria chromosomes.
Homologues: - answer Carry matching genetic information, one from the mother and
one from the father
Allele - answer The alternate forms of a gene on homologous chromosomes
Homozygous vs heterozygous - answer Homozygous: two alleles that are the same
Heterozygous: two alleles that are different. An organism with two different alleles for a
single trait is said to be heterozygous for that trait.
, Chromatin and chromsome - answer -Chromatin is made up of DNA and proteins that is
condensed onto nucleosomes.
-Once the chromatin continues to to get condensed and packed even more it will
become chromosome.
Differentiate heterochromatin from euchromatin - answer -Heterochromatin is
chromatin is very tightly packed and not easily accessible.
-Euchromatin: open and actively involved in gene expression (transcription)?
Nucleosome composition - answer -146 base pairs of DNA that wraps and makes 1.65
negative superhelical turns around the octamer
-The octamer has 8 histone proteins,
2(H2a), 2(H2b), 2(H3), 2(H4)
-. A nucleosome looks like a bead like structure that is divided up into units by a double
helix that is not wound or linker regions.
Gene - answer -a region of DNA producing a polypeptide or a functional RNA molecuel
-The fundamental physical and functional unit of inheritance that encodes a functional
product is
Exons vs introns - answer Exons are the coding regions that actually code for a
something (usually proteins) and can be transcribed. Introns are spliced out if the gene
because they dont code for anything.
Nucleic acids vs nucleotides - answer -Nucleic Acids are the basic unit of DNA and RNA
and they are made up of nucleotides.
-Nucleotides are bound together through the bond between their phosphate and
hydroxyl groups located on their sugars.
Nucleotide composition - answer Nucleotides are made up of a nitrogenous base, a
