Lab 12 - Human Genetics and Gene Expression

Testcross

the mating between an individual of unknown genotype for a particular character and an individual that is homozygous recessive for that same character

Penetrance

the likelihood that an individual with a given gene will express that phenotype

Polygenic inheritance

the inheritance of a phenotypic character in which the expression depends on the effect of many genes

Pedigree

a diagram of a a family history that follows the inheritance of a genetic trait over a number of generations

A pedigree for an autosomal dominant disorder can be recognized because every affected individual has at least one:

affected parent

There is also a high probability that we will see the disorder in every

Generation

The Roman Numerals represent

Generations

Codominance

the expression of two different alleles of a gene in heterozygote

What is the Rh factor?

The terms “positive” or “negative” listed after ABO blood type refer to the Rh factor, a different blood antigen

Why is it called “Rh”?

First identified in the blood or rhesus monkeys

The female has what type of chromosome in every diploid cell?

X

The Male has what type of chromosome in every diploid cell?

XY

Who determines the sex (X or Y) of offspring?

Human male

Mutation

any permanent, heritable change in the nucleotide sequence of DNA

Nondisjunction

an accident in meiosis in which a pair of homologous chromosomes or a pair of sister chromatids fail to separate anaphase

Non-disjunction of an autosome is the most common cause of

Trisomy 21 (down syndrome)

Barr Body

a density stained mass in the nucleus of a cell that represents the inactive X chromosome(s)

X chromosome inactivation

the shutting down of a majority of genes on all but one x chromosome in a cell

Name the four bases that make up DNA’s chemical alphabet

A T C G

Codon

a three nucleotide sequence that specifies a particular amine acid

Where is the DNA molecule during protein synthesis?

nucleus

What is the chemical messenger that carries the instructions of DNA to the cytoplasm for protein synthesis?

RNA (mRNA)

Flow information to the cell

DNA to mRNA to Protein

genetic code

a table that shows which mRNA codons for which amino acids

The genetic code is written in the language of

mRNA nucleotides

To know which amino acid is to be correctly added to the growing polypeptide chain next, you must translate from?

mRNA strands of codons

You see in this pedigree that both parents are affected with a disorder, but their offspring is not affected. This tells you that…..

the allele(s) causing the disorder is/are dominant

If being a student at Los Angeles Pierce College (LAPC) is dominantly inherited, and your genotype is P-, you know that…..

You can be either heterozygous or homozygous dominant for the Pierce College student character

A man cannot be the father of a child with O blood if the man has…..

Type AB blood or Klinefelter syndrome

If you have type A blood, your genotype is:

I^AI^A or I^Ai

When nondisjunction occurs, it can cause

All Choices (Klinefelter syndrome, Trisomy 21, Trisomy X, XXY syndrome)

If a male who has hemophilia reproduces with a women who is a carrier for this disorder, what is the probability that a son will have hemophilia?

50%

If you were given the tRNA anti-codon AUG, what amino acid would it code for?

Tyrosine

Regarding nucleic acid structure, which of the following is/are true about the base uracil?

It is complementary to adenine and it is in RNA, but not DNA

What will be the mRNA codon that corresponds to the DNA triplet GTA?

CAU

How could you be a female and have a karyotype of 46, XY?

You have androgen insensitively syndrome