Chapter 4-5 Study Guide Flashcards
What factors can determine a human’s height?
Several genes working together and diet/environment
Identify the reason why eye color is not necessarily controlled by a single gene.
Traits that show a large number of phenotypes are controlled by many genes and eye color has lots of different phenotypes.
Define cloning and how does offspring compare to the parent?
Cloning = produces offspring that is genetically identical to the parent. The offspring looks exactly like the parent.
By creating a punnett square, would it be possible for a person with AB blood to have a child with O blood?
Not possible. A person with O blood has to get two recessive alleles, one from mom and one from dad. If one parent has AB blood, they do not have an O allele to pass on.
Is it possible for a boy to get an X chromosome from his father? Why or why not?
No, the mother only has X to pass on so if the child receives an X from mom and an X from dad it would be a girl, not a boy. To be a boy, the dad has to give a Y.
Identify the differences between hybridization and inbreeding.
Hybridization = The crossing of two genetically different individuals. Inbreeding = Crossing two genetically similar individuals.
What is the purpose of a Punnett Square?
To show all the possible outcomes of a genetic cross.
What does the notation TT mean in genetics? What does the notation Tt mean in genetics?
TT = two dominant alleles Tt = one dominant allele and one recessive allele
Contrast the effects of harmful and helpful mutations.
Harmful mutation = Mutation that reduces the organism’s chances for survival and reproduction.
Helpful mutation = Mutation that increases the organism’s chances for survival and reproduction.
How do codominant genes work?
Both alleles show up in the offspring, neither dominant nor recessive.
Explain why recessive traits can never be hybrid.
A hybrid has one dominant allele and one recessive allele. If you have the recessive trait, that means you would have two recessive alleles, so it would not be a hybrid.
How is RNA different from DNA?
RNA is a single strand whereas DNA is two strands, like a twisted ladder.
What are DNA and RNA nitrogen bases?
DNA bases: Adenine, Thymine, Guanine, Cytosine
RNA bases: Adenine, Uracil, Guanine, Cytosine
In DNA and RNA, which bases pair together?
DNA base pairs: Adenine/Thymine, Guanine/Cytosine
RNA base pairs: Adenine/Uracil, Guanine/Cytosine
What determines the genetic code?
The order of nitrogen bases along a gene.
When sex cells combine, each sex cell will contribute ____ amount of chromosomes from the body cell.
Half
What happens during meiosis?
Chromosome pairs separate and are distributed into new sex cells.
Sex-linked genes are located on ____________________.
The X and Y chromosome
How does the Human Genome Project help genetic engineers produce human proteins?
To produce a protein, geneticists must know the sequence of DNA bases that code for a protein.
Give an example of a benefit of genetic engineering.
Creating human insulin to treat for diabetes.
What is the best way to predict the probability of a baby having cystic fibrosis?
Study the family’s pedigree chart
What are chromosomes made up of?
Many genes joined together
What are the allele combinations of females and males?
Female = XX Male = XY
Give one example of a trait controlled by a gene with multiple alleles.
Blood type
Which trait that we talked about can be altered by variations in the environment?
Height
How does a geneticist use pedigrees?
To trace the inheritance of traits in humans
Why are sex-linked traits more common in males than females?
When it comes to sex-linked traits, males only have to receive one recessive allele to have the trait.
Females have to receive two recessive alleles to have the trait. It is easier to receive one allele than it is to receive two alleles.
What are genetic disorders caused by?
DNA mutations or changes in chromosomes
Why can’t a male be a carrier of colorblindness?
A carrier is someone who has one dominant allele and one recessive allele. Since colorblindness is a sex-linked trait, males only have to receive one recessive allele to be colorblind. Therefore, they would only have one recessive allele, so they would not have one dominant and one recessive, which would be a carrier. In sex-linked genes, females are the only carriers.
What do circles and squares represent on a pedigree chart?
Females = circles Males = squares
How can we tell if the trait traced by a pedigree is a sex-linked trait?
Females are the only carriers
Define genes.
The set of information that controls a trait; a segment of DNA on a chromosome that codes for a specific trait.
Define hybrid.
An organism that has two different alleles for a trait; An organism that is heterozygous for a particular trait.
Define homozygous.
Having two identical alleles for a trait.
Define heterozygous.
Having two different alleles for a trait.
Define probability.
A number that describes how likely it is that an event will occur.
Define genotype.
An organism’s genetic makeup, or allele combination.
Define phenotype.
An organism’s physical appearance, or visible traits.
Define allele.
The different forms of a gene.
Define multiple alleles.
Three or more forms of a gene that code for a single trait.
Define pedigree.
A chart or “family tree” that tracks which members of a family have a particular trait.
Define genome.
All of the DNA in one cell of an organism.
Define inbreeding.
A selective breeding method in which two individuals with identical or similar sets of alleles are crossed.
Define carrier.
A person who has one recessive allele for a trait, but does not have the trait.
Define genetics.
The scientific study of heredity.
Define mutation.
A change in a gene or chromosome.
Define codominance.
A condition in which neither of the two alleles in the gene is dominant or recessive.
