genetics Flashcards
a piece of DNA that codes for a protein and controls a trait
gene
the different forms of a gene
alleles
having two identical alleles for a trait, TT or tt
homozygous
having two different alleles for a trait, Tt
heterozygous
the likelihood that an event will occur
probability
an organism’s genetic makeup
genotype
an organismm’s physical appearance
phenotype
when a trait is controlled by 3 or more alleles
multiple allele trait
a chart or “family tree” that shows the inheritance of a trait
pedigree
all the DNA of an organism
genome
a type of selective breeding where two related individuals or individuals with similar sets of alleles are crossed
inbreeding
an organism created by mixing two unlike organisms having different forms of a trait, mixing a horse and a donkey
hybrid - mule
What two factors can determine a person’s height?
genes (alleles) and environment (diet)
Identify the reason why eye color is not likely controlled by a single gene?
There are a large number of possible phenotypes which indicates more than one gene.
Define cloning, and explain how the offspring compares to the parent.
making copies of the organism, clones are exactly the same DNA as the original.
By creating a Punnett square, is it possible for a person with AB blood to have a child with O blood?
no - The AB person will pass on either an A or a B. To be O, you have to have 2 genes for O.
Is it possible for a boy to get an X from his father?
no he gets his Y from his father and the X from his mother. If he got an X from his father, he would be a girl.
Identify the difference between hybridization and inbreeding.
inbreeding - breed related individuals with similar traits
hybridization - breeds unrelated individuals with different traits to make new traits
What is the purpose of a Punnett square
to show the possible traits offspring could get
Explain the chromosome theory of inheritance
genes are passed from parents to offspring on chromosomes
How are mutations helpful?
give you a trait that helps you survive - like blending in with your environment
How are mutations harmful?
they make it harder for you to survive - like making you stand out in your environment
How do codominant traits work?
the genes are equally expressed
Why are recessive traits not hybrids?
You would show the dominant allele if you have one gene for each. You need 2 recessive genes to be recessive.
What are the nitrogen bases of DNA and RNA?
DNA - adenine, thymine, guanine and cytosine
RNA - adenine, uracil, guanine and cytosine
What determines the genetic code?
the order of nitrogen bases
When sex cells combine, each sex cell contributes how many of the chromosomes?
half
What happens during meiosis?
cells divide twice to make 4 cells with half the chromosomes - making eggs and sperm
Sex linked genes are located where?
X and Y chromosomes
How does the human genome project help genetic engineers produce human proteins?
we have to know what genes there are in the human DNA and what they code for before we can isolate them to make proteins
What is the best way to predict the probability of a baby having cystic fibrosis?
pedigree
Give an example of a benefit of genetic engineering.
making better crops that are drought resistant, pest resistant, and more nutritious
Describe cystic fibrosis
abnormal mucous in lungs and intestines
What alleles make a male? a female?
male - XY
female - XX
Give an example of a trait controlled by multiple alleles.
blood type - A, B, O
What is an example of a trait that can be altered by changes in the environment.
height
How does a geneticist use a pedigree?
trace the inheritance of a trait in a family
Why do males more commonly get sex-linked traits?
often on X chromosome and recessive - a male only has to get one copy of the bad allele
