Chapter 4

Genome

Remember that the genome is all the genes of one individual, estimated at 25,000-30,000 genes in humans.

Gene

Which of the following terms refers to a segment of DNA that codes for the production of a molecule of RNA?

Penetrance

A genotype does not inevitably produce a phenotype. Which term refers to the percentage of a population with a given genotype that actually exhibits a predicted phenotype.

Multiple allele

ABO blood type is a trait that demonstrates which type of inheritance?

homologus chromosomes

Cells contain pairs of chromosomes. Since they are the same size and shape and also code for the same information, each pair of chromosomes is called which of the following?

can cause obesity cause a stem cell to become a liver cell can cause cancer

Epigenetic effects ______.

gene expression

Epigenetic effects alter ______.

Polygenic inheritance

Eye color and skin color are traits determined by genes at multiple loci. They are examples of which type of inheritance?

free ribosomes, polyribosomes on the RER

If a protein is going to be used in the cytosol, it is likely to be made by ______. However, if it is going to be secreted from the cell, it is made by ______.

50%

If the mother is a carrier for hemophilia (X-linked trait) but the father does not have this condition, what is the chance that their son will have the disease?

Their expression is masked in the presence of a dominant allele. They are expressed only when present on both of the homologous chromosomes.

Indicate which of the following is true with regard to recessive alleles.

X-linked

Males are more likely than females to inherit a genetic disease if the gene for it is which of the following?

Homologous

One member of each_____ pair of chromosomes is inherited from the individual's mother and the other from the father.

Genes encode enzymes that synthesize these products.

Since there are no genes coding for carbohydrates, nucleic acids, or lipids, how do cells produce them?

phospholipids steroids glycogen

There are no genes that directly code for ______.

False

True or false: Dominant alleles are always more common in the gene pool than recessive alleles.

False

True or false: Genes produce their products nonstop, 24-hours a day.

True

True or false: There are no genes for glycogen, fat, steroids, phospholipids, and many other compounds, yet their synthesis is under indirect genetic control.

The nucleotide sequence in DNA

What determines the amino acid sequence of a protein?

rough endoplasmic reticulum, transport vesicle

When a protein must be exported outside the cell, it is synthesized in ribosomes bound to the ______ (indicated by a "A"). Then it is modified and packaged into a ______ (indicated by "B").

In the nucleus

Where does the making of mRNA from DNA take place?

The genetic code allows 20 amino acid to be coded by only 4 different nucleotides. The genetic code relates mRNA codons to protein structure. The genetic code is expressed as three-nucleotide long sequences called codons.

Which of the following are true statements about the genetic code?

Which proteins a cell makes is determined by which genes are activated in that cell.

Which of the following is a true statement?

It is caused by the recessive allele. Individuals with type O blood are homozygous for this trait.

Which of the following statements is true regarding type O blood?

DNA contains the genetic code that determines the amino acid sequences of proteins.

Which statement best summarizes the role of DNA in protein synthesis?

Multiple allele inheritance

Which term refers to a type of inheritance in which three or more alleles exist for the same gene?

Dominant

Which type of allele will mask the expression of a recessive allele in a heterozygote?

Polygenic

Which type of inheritance is a phenomenon in which two or more genes contribute to a single phenotypic trait?

Chromosome

is a complex of DNA and protein carrying the genetic material of a nucleus.

Pleiotropy

is a phenomenon in which one gene produces multiple phenotypic effects.

Gene

is an information-containing segment of DNA that codes for the production of a molecule of RNA, and that in most cases codes for one or more proteins.

Chromatin

is the filamentous material in the interphase nucleus, composed of DNA and associated proteins.

Polygenic inheritance

s a phenomenon in which genes at two or more loci, or even on different chromosomes, contribute to a single phenotypic trait.