Alleles are described as ______.
Alternate versions of a gene
A true-breeding plant that produces yellow seeds is crossed with a true-breeding plant that produces green seeds. The seeds of all of the offspring are yellow. Why?
The yellow allele is dominant to the green allele
The parents of a child with unusual disease symptoms take the child to a doctor for help. The doctor suspects that the condition might have a genetic basis. She recommends that the child be taken to a specialty clinic where physicians and staff members are trained to diagnose genetic diseases and counsel parents. Ultimately, the child is diagnosed with a rare recessively inherited disease. The parents are tested for the gene, and both are found to be heterozygous. The parents want to have another child but are afraid this child will also be affected.
A true-breeding plant that produces yellow seeds is crossed with a true-breeding plant that produces green seeds. The F1 plants have yellow seeds. What is the expected phenotypic ratio of seed color of the offspring of an F1 × F1 cross?
Attached earlobes are recessive to free earlobes. What genotypic ratio is expected when an individual with attached earlobes mates with an individual heterozygous for free earlobes?
Attached earlobes are recessive to free earlobes. What is the probability of having a child with attached earlobes when an individual with attached earlobes mates with an individual heterozygous for free earlobes?
An individual who is homozygous ______.
carries two copies of the same allele for a gene
Which of these crosses will only produce heterozygous offspring?
AA x aa
To determine the phenotype of an individual who expresses a dominant trait, you would cross that individual with an individual who ______.
is homozygous recessive for that trait
A couple has two female children. What is the probability that their next child will be male?
An individual heterozygous for cystic fibrosis ______.
is a carrier
Achondroplasia is a form of dwarfism caused by a dominant allele. The homozygous dominant genotype causes death, so individuals who have this condition are all heterozygotes. If a person with achondroplasia mates with a person who does not have achondroplasia, what percentage of their children would be expected to have achondroplasia?
What is the key to the recognition of incomplete dominance?
The phenotype of the heterozygote falls between the phenotypes of the homozygotes.
An individual with (naturally) curly hair and an individual with (naturally) straight hair mate; all of their offspring have (naturally) wavy hair. If an individual with wavy hair mates with an individual with straight hair, what is the probability that their child will have curly hair?
Marfan syndrome is the result of inheriting a single allele. Individuals with Marfan syndrome are tall and long-limbed, and have both cardiovascular and eye defects. The inheritance of Marfan syndrome is an example of ______.
In humans, the inheritance of ______ is best explained as being polygenic.
In the accompanying art you see a table with the actual number of offspring that resulted from a dihybrid cross. The numbers do not show the 9:3:3:1 ratio predicted. One phenotype occurred more than predicted; another occurred less. The reason could be because ______.
some of the alleles were linked
Recombinant offspring were produced by the mating shown in the accompanying art. What is the recombination frequency of purple round and red long offspring?
Assume that having three nostrils is inherited as a sex-linked trait on the Y chromosome. A man with three nostrils has a daughter who has a son with a man who has only two nostrils. What is the probability that the three-nostriled man's grandson has three nostrils?
Red-green color blindness is inherited as a sex-linked recessive trait. The gene is found on the X chromosome. How can a man with normal color vision father a daughter who is red-green color-blind?
He can't (unless there is a mutation).
At one point, you were just an undifferentiated, single cell. You are now made of many cells; some of these cells function as liver cells, some as muscle cells, some as red blood cells, while others play different roles. What name is given to the process that is responsible for this?
cellular differentiation
Consider the following figure, which outlines cloning by nuclear transplantation. Why does the clone not resemble the surrogate mother?
The clone would exhibit characteristics of the genetic donor, not the surrogate.
To make a clone - a genetically identical organism - from a mammalian cell, the cell must ______.
be dedifferentiated
Possible uses of reproductive cloning include ______.
the production of potentially valuable drugs the production of genetically identical animals for experimentation
the production of organs in pigs for transplant into humans
restocking populations of endangered animals
-------all of the above.
What is a difference between embryonic and adult stem cells?
Embryonic stem cells are undifferentiated; adult stem cells are partially differentiated.
Examine the figure below. In a typical colon cancer, the first step is ______.
the mutation of a proto-oncogene, producing an oncogene
Many proto-oncogenes regulate ______.
cell division
Inheritance of certain genes increases the risk of getting certain cancers; thus, it can be said that ______.
predisposition to these cancers is inherited
______ is(are) responsible for more cancers than any other carcinogen.
More people die of ______ cancer than of any other cancer.
Which of the following is the best definition for recombinant DNA?
DNA that carries genes from two different sources
The world's first genetically engineered pharmaceutical product was ______.
Which of these can act as a vector to introduce new genes into a cell?
"Sticky ends" are produced as a result of the action of ______.
a restriction enzyme
A DNA fragment with a sticky end that reads -ATTCG will bind with another DNA fragment with a sticky end that reads ______.
Which enzyme is used to bind DNA fragments together?
DNA ligase
The following figure shows that gel electrophoresis can be used to separate repetitive DNA sequences. Gel electrophoresis separates DNA fragments because ______.
the DNA fragments have different lengths
You are attempting to link an individual to a crime. The only evidence you have is a tiny drop of blood. How can you use this drop of blood to make the association?
You can use PCR to increase the amount of DNA available for restriction fragment analysis.
Gel electrophoresis separates DNA fragments on the basis of differences in their ______.
The human genome contains approximately ______ genes.
Approximately what percentage of the human genome consists of noncoding DNA?
The Human Genome Project has the potential to ______.
play a role in all of the choices listed here
Which of these statements can be logically inferred from the amount of DNA shared by chimpanzees and humans?
Humans and chimpanzees share a relatively recent common ancestor.
Genetically modifying human ______ cells may directly affect future generations.
The backbone of DNA consists of ______.
a repeating sugar-phosphate-sugar-phosphate pattern
RNA contains the nitrogenous base ______ instead of ______, which is only found in DNA.
uracil . . . thymine
If adenine makes up 20% of the bases in a DNA double helix, what percent of the bases are guanine?
If one strand of a DNA double helix has the sequence GTCCAT, what is the sequence of the other strand?
Who discovered the structure of DNA?
Watson and Crick
Evidence for the spiral nature of DNA came from ______.
X-ray crystallography studies
During replication, ______ are the enzymes responsible for joining the nucleotides of a new DNA strand together.
DNA polymerases
Examine the genetic code table, shown below. The codon AGC codes for the amino acid ______.
Consider the following figure. It indicates that a single amino acid substitution ______.
may alter a protein so that it no longer functions properly
How many amino acids are common to all living systems?
How many nucleotides make up a codon?
The shared genetic code of all life on Earth is evidence that ______.
all life shares a common ancestry
If a strand of DNA has the sequence AAGCTC, transcription will result in a(n) ______.
single RNA strand with the sequence UUCGAG
The region of DNA where RNA synthesis begins is the ______.
The expressed (coding) regions of eukaryotic genes are called ______.
The DNA codon AGT codes for an amino acid carried by a tRNA with the anticodon ______.
Where is translation accomplished?
A mutation within a gene that will insert a premature stop codon in mRNA would ______.
result in a shortened polypeptide chain
What is the ultimate source of all diversity?