Biology : 5. GENETICS
How can knowledge of genetics be used to improve the agricultural production of food?
Using our knowledge of genetics, we can change, improve, add or get rid of certain genes for the better of the crop and food industry. Take, for example, Bt corn. What this is, is corn that has had its genetics changed for better production. What farmers saw was that there were insects and parasites coming and eating all the corn. They would then apply too much spray on the corn to get these insects away that it would harm the people who at it. How they fixed this was changed the corns genetics to produce a similar chemical. This chemical, as soon as the insect takes a bit would kill it. This, however, has no effect on humans since we do not have the same digestive track as these insects, and even if we did, our stomachs are too acidic and this poison would just die right away.
Why didn't Charles Edward, the grandson of Queen Victoria, receive hemophilia from his father Leopold?
because the disease is not on the "Y" chromosome and Helena did not have the trait
"Linkage" refers to genes for different traits
being located on the same chromosome
A pedigree chart can show a trait that is:
both dominant and a mutation
If the parent genotypes are Aa and Aa, the offspring are expected to be: 1/2 AA and 1/2aa all Aa 1/4 AA, 1/2 Aa, 1/4 aa 3/4 AA and 1/4 aa
1/4 AA, 1/2 Aa, 1/4 aa
DNA was discovered in:
1953
The second generation phenotypes resulting from the cross of true-breeding monohybrid pollination will display a ratio of: 1:4 1:2 1:3 none of the above
1:3
Indicate the phenotypic ratio of crossing the offspring of the agouti and chinchilla. 3/4 agouti, 1/4 chinchilla 3/4 agouti, 1/4 albino 1/2 agouti, 1/2 albino 3/4 albino, 1/4 agouti
3/4 agouti, 1/4 chinchilla
This cross will yield four phenotypes in the 1:1:1:1 ratio: rryy x rryy RrYy x rryy RrYy x RrYy RRYY x rryy
RrYy x rryy
Radiation damage has hereditary effects if it: changes proteins in the cytoplasm alters the DNA in somatic cells alters the DNA is autosomes alters the DNA in gametes
alters the DNA in gametes
Mendel's principle of segregation implies that the two members of an allelic pair of genes:
are distributed to separate gametes
Nitrogen bases are found on the DNA twisted ladder:
as the rungs
Within a set of human chromosomes, 22 pairs are called:
autosomes
Each P1 parent of a monohybrid cross has completely identical genes. True False
false
Genes that carry contrasting inheritance factors are called:
heterozygotes
An organism possesses one copy of each allele type for a given gene. It is said to be... homozygous recessive for both alleles heterozygous for the gene genotypically inactive
heterozygous for the gene
When the alleles of a gene pair are identical they are said to be:
homozygous
When neither of the genes of a pair are dominant nor recessive, the genes are said to be:
incomplete dominant alleles
Segregation and independent assortment of genetic material occurs during:
meiosis
Sex cells are produced in a process called____
meiosis
In the Watson-Crick model of a double helix, the "steps" of the "spiral staircase" are composed of:
nitrogen bases
Failure of homologous chromosomes to separate during meiosis is called gene _______ .
nondisjunction
Represented by word descriptions, such as black and short-haired:
phenotype only
What is meant by homologous chromosomes? chromosomes are found in pairs the gene's alleles are found in matched chromosome pairs all chromosomes contain the same genes each homologous chromosome has identical genotypes
the gene's alleles are found in matched chromosome pairs
Fertilization produces in the offspring:
double the haploid number of chromosomes
How can a mutation be inherited?
through gamete reproduction and fertilization through meiosis and fertilization
As a result of nondisjunction, a female gamete may contain:
two sex chromosomes no sex chromosomes