Biology- Heredity Honors

genetics

study of heredity

Allele

a different version of a gene

Genotype

Genetic makeup

recessive

Must inherit 2 copies to produce phenotype

Homozygous

The same

Homozygous two other names

purebred, true-breeding

Heredity

the passing on of genetic characteristics,

Gene

Segment of DNA that codes a protein

phenotype

physical trait, not always visible

Homologous chromosomes

Where alleles are kept

Genome

collection of all organisms genes

Heterozygous/hybrid

two different alleles are inherited

linked genes

progeny

Offspring

What is a phenotypic ratio

Report resulting phenotypes of cross

What is a genotypic ratio

A way to report the resulting genotypes of a cross

How to show a genotypic ratio

\# hom dom: # hetero: # hom rec

how to show a phenotypic ratio

\#dom: # rec

In a plant called jimsonweed, flowers can be white or purp.e. A jimonsweed plant with white flowers is crossed with jimsonweed plant with purple flowers. All of the offspring have purple flowers. Based on the results, which of the following statments most likely describes the alleles for flower color in jimsonweed.

The allele for purple flowers is dominant to the allele for white flowers??

What describes a genotype

the allele/genetic makeup of an organism

Brown eyes: blue eyes 3:1 What is the ratio of phenotypes in a Punnett square

phenotypic ratio

What is the genotype for a pea plan homozygous for round seeds (R) and heterozygous for yellow seeds (Y)

RRYy

What is an example of a phenotype

Blue

True or false: a phonotype describes the physical expression of a gene, or how something looks

true

In peas, round is dominant to wrinkled and yellow is dominant to green. Based on this dihybrid cross, what fraction of the offspring will have wrinkled yellow seeds

3

There are multiple alleles for the ABO blood group Why are there only two of these alleles present in any one individual

Each parent contributes one allele

In pea plants Tall stems (T) are dominant to short stems (t) cross a homozygous tall plant with a homozygous recessive plant, what is the phenotypic ratio?

4:0

Which of the following is an example of a genotype

Bb

Which of the following is an example of a homozygous recessive genotype

rr

What are the possible gametes from AaBB

AB, AB, aB, aB

A male beetle has the genotype Ttbb. If this beetle mates with a female with genotype TTBb, what is the chance their offspring will have the genotype TtBb

4 /16

How many alleles does one have for each gene

2

Why is the gene for a disorder more likely to be found on the X chromosome than Y

The X chromosome has more genes

In guinea pigs, Black fur (B) is dominant to white (b), cross Bb x bb and determine genotypic ratio for offspring

0:2:2

A baby dragon recieves two dominant alleles which codes for dark green skin; however, they also receive two recessive alleles for skin pigment production and therefore are albino, none of teh dark green is able to show. The specific pattern of inheritance described is

recessive epistasis

What 3 alleles are responsible for the phenotypic expression of ABO blood types

IA, IB, I (recessive)

What type of inheritance is determined by multiple genes and there can be a septum of pho types

polygenic

Tomato plants usually have hairy stems. Hairless stems are present in tomato plants that are homozygous recessive for this trait. If the stem characteristics are determined by a single gene, what is the expected outcome of crossing two tomato plants that are heterozygous for hairy stems

75% hairy, 25% not

If a person has type B blood, the pho type is B. What can this genotype be

IBIB or IBi

In some carnations, flower color exhibits codominance. When crosses red (R) and white (r) flowers make speckled flowers (Rr) that show both colors. Complete a cross between 2 specked flowers and find the genotype ratio

1:2:1

H= normal blood clotting

H= hemophilia

XHXh x XHY

What is the probability that any of their offspring will have hemophilia

1/4

The ratio of homozygous dominant to heterozygous to homozygous recessive offspring

genotypic ratio

What are the 4 possible phenotypes for human blood type based solely on the ABO blood group

Type O, A, B, AB

A father has type AB blood and the mother has type O. Which option matches the phenotypic probabilities for their offspring

A: 50% B: 50%

A man with type B blood is wondering if he is the father of a type A baby. the mother is type A. Could this man be the father?

Yes, could be heterozygous

In interaction where one gene masks another gene is called

Epistasis

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In anadaluian fowls, black individuals (BB) and white individuals (bb) are homozygous. Heterozygous individuals are grey (Bb). Cross a black fowl with a white fowl. What is the photo pic ratio.

This pattern of inheritance results in heterozygotes with a mixed or blended phenotype

when crossing two parents who are heterozygous for two traits, what is the phenotypic ratio for the progeny?

A ___ is a segment of DNA that codes for a particular protein, which leads to a particular trait

gene

Genes/rains located close to each other on the same chromosome and therefore more likely to be passed on together are known as

Linked

Hemophilia is a recessive x-linked disorder. Which genotype represents a femele who is a carrier for hemophilia

XHXh

How many alleles do you get from each parent

1

the letters on the top and the side of a Punnett square represent

The possible alleles given before meiosis

Examples of this pattern of inheritance include eye color, hair color, skin tone and height

Polygenic

What pattern of non-Mendelian inheritance is shown by ABO blood group

multiple alleles

B=black, b= chocolate. Some labs inherit black or brown fur alleles but have light fur due to the effect of a different gene. This shows which pattern of inheritance

Epistasis

What is the probability that the offspring from the cross AaBB x Aabb will be heterozygous for both traits

1/2

Genes/traits located close to each other on the same chromosome and therefore more likely to be passed on together are known as

Linked

____ is the father of modern genetics

Gregor Mendel

Who was Mendel?

A monk in the 1800s that investigated the inheritance of physical traits of pea plants

We inherit two alleles for each gene because

chromosomes exist in homologous pairs

Mendel needed to describe the way that the alleles… he did so on his observations of traits in pea plants

interacted

alleles can be classified in two ways

dominant, recessive

Allele inhericance affects our

physical appearance

Genotype determines

phenotype

Mendel did experiments over ___ of pea plants

generations

3 steps of medals experiments

p gen, f1-gen, f2-gen

The F1 cross: 2 steps

first, p-gen crossed, then f1 gen: the cycle of mixing the parents gen

Teh f2 cross:

mixes the F1 plants, conches if they are hetero or homozygous

Go over F1, F2, and p-gen genotypes and phenotypes

The F1 gen

Self-pollinates

What is a test cross

Organism with dominant phenotype x organism with recessive

What is a dihybrid cross

Uses two traits in a Punnett square

Dihybrid experiments- mendels experiments , P-gen- YYRR x yyrr, f1 gen- 100% yellow round peas, f2=

9:3:3: yellow round, green round, yellow wrinkled: green wrinkled

We can predict _____ that would form from parent genotypes

Possible gametes

What are examples of gametes that could be made from HhRRNn

HRn, HRN, HRN, hRn

Incomplete dominance

both show up blended in a heterozygote

In incomplete dominance and codominance there is no true

dominant/recessive trait

Incomplete dominance with mendels experiment

p gen: red x white, f1: 100% pink flowers f2: 1/4 red, 1/2 pink, 1/4 white

Codominance:

two phenotypes appear in a pattern

in codominance, heterozygous have a ____ appearance

patterned

Punnett squares with codominance traits: use

superscripts to show heterozygous (codominance)

Codominance in mendels experiment: p- red x white flower

f1- 100% spotted f2- 25% red, 50% spotted, 25% white

linked genes

some alleles are not separated form each other during meiosis, too close to one another

Multiple alleles

2+ alleles for a gene exist

An organism with multiple alleles still only inherit…

2

What is a common example of multiple alleles/codominance

Blood type

Humans have ____ blood groups

ABO

Polygenic inheritance

a single trait is influenced by many (2+) genes

Some alleles in polygenic inheritance contribute an ____ on phenotype

additive effect

_____ have additive effect

certain alleles

What is an example of polygenic inheritance

producing more pigment in height, skin tone, hair color, and eye color

________ fall along a spectrum

Polygenic phenotypes

When determining polygenic phenotypes, look for where it fits on the

spectrum

What is epistatis

A form of polygenic interaction in which one gene masks or hides the phenotype produced another gene

What is recessive epistasis

Masking the gene requires two recessive alleles to hid the phenotype

dominant epistasis

masking the gene only requires one dominant allele to hid the phenotype

Two common examples of epistasis

Labs, albinism

In the Y-chromosome, there are ______ genes

Few