Bio Unit 2 quiz 2

Alleles meaning

different form of the same gene

Dominant allele meaning

 the allele that if present, is always expressed

how is dominant allele expressed

Capital letter

what is recessive allele and how is it expressed

the allele that is expressed only if the dominant allele is not present

-expressed with lowercase letter

Homozygous meaning

describes an individual that carries two of the same alleles for a given characteristic

heterozygous meaning

describes an individual that carries two different alleles for a given characteristic

example of homozygous

mom and dad both have brown eyes

example of heterozygous

mom has brown eyes dad has blue eyes

Genotype: meaning

genetic makeup of an individual

Phenotype meaning

an individual's outward appearance (what you see)

who is the father of genetics and why did he crossbreed pea plants in his garden to oberserve patterns of inheritance

-gregor mendel

-they reproduce quickly

-easily observable traits

-can self pollinate or cross pollinate

what is self pollinate

has both male and female reproductive parts

what did father of genetics do (in depth)

• He started with true-breeding pea plants (plants that always produce the same trait, like always tall or always short).

• To control the experiment, he removed the anthers (the pollen-making parts) from one plant so it couldn’t self-pollinate.

• Then he took pollen from a different pea plant and manually transferred it to the first plant. This is called cross-pollination.

what did father of genetics do (simple)

He carefully “mixed” two different parent plants on purpose to see what traits their offspring would have.

By doing this over many generations, Mendel discovered the basic rules of inheritance—like how some traits are dominant and others are recessive.

3:1 represents what

the ratio of dominant traits to recessive traits

explain the law of segregration

• Inherited traits (like the traits you gave your “baby”) are inherited from EACH parent

• Parent organisms can only donate one copy of each gene in their gametes (sex cells) because during meiosis two copies of each gene separate (segregate)

whats a punnet square used for

•  a grid-like diagram that summarises every possible combination of allele from each parent.

It is used to predict the  proportion of genotypes and phenotypes  in the offspring resulting from a  cross between two individuals

what is incomplete dominance and example

• Occurs when neither allele is dominant over the other

• Results in blending (partial expression of both traits)

• -Red flower (RR) × White flower (WW)

• Offspring = Pink flowers (RW)

whats complete dominance

If a dominant gene is present, it overpowers the recessive one, so you only see the dominant trait.

whats codominance

Codominance is when both traits show up fully at the same time—neither one hides the other and they don’t blend.

Human blood type is both a ____ and ____ genetic trait

co-dominant, completetly dominant

what are antigens

proteins on the surface of red blood cells

what are the three possible alleles for blood type gene

I^A, I^B, and i

I^A 🡪codes for___

I^B 🡪codes for___

i codes for___

-a antigen

-b antigen

-no antigen

If the recessive allele (i) is paired with either I^A or I^B, the individual expresses the ____ allele this is an example of____

-dominant

-complete

If an individual has both I^A and I^B alleles, their RBCs possess both A and B surface antigens, this is an example of ___

codominance

Type O= universal donor meaning

can give blood to everyone

Type AB=universal recipient meaning

can recieve blood from everyone

type a can recieve from

O and A

type O can recieve from

only o

type B can recieve from

B and O

what was the first discovery of Sex-Linked Inheritance

Thomas Morgan concluded that the gene for eye colour was found on the X chromosome

explain sex-linked inhertiance

• Some genes are found on the X or Y chromosomes and therefore occur more frequently in one sex

whats Haemophilia

genetic bleeding disorder in which blood does not clot properly

whats a pedigree

A pedigree is a chart of the genetic history of a family over several generations.

If most of the males in the pedigree are affected the disorder is likely____

x-linked

f it is a 50/50 ratio between men and female the disorder is likely___

autosomal

explain autosomal

• In an autosomal disorder, the disorder is not found on the X or Y chromosome.  It is found on the other 22 chromosomes in the human body.  This means that men and women have an equal chance of having the disorder.  The mother and father can be homozygous dominant, heterozygous, and homozygous recessive

how do yk if the disorder is dominant

• If the disorder is dominant, one of the parents must have the disorder.

how to know if the disorder is recessive

• If the disorder is recessive, neither parent has to have the disorder because they can be heterozygous.

steps to begin to interpret a pedigree

• determine if the disease or condition is autosomal or X-linked and dominant or recessive  then start listing potential genotypes.