Science 6B

Question 0

What are Mendel’s factors called today?

Answer 0

Alleles

Question 1

How many chromosomes does a normal human cell have?

Answer 1

46 chromosomes (23 pairs)

Question 2

What do the letters along the top and side of a Punnett square represent?

Answer 2

Mother on top

Father on side

Question 3

(dimples is dominant over no dimples)

A woman who is purebred for dimples marries a man who is hybrid for dimples. Is it possible for any of their children not to have dimples? Draw a Punnett square to prove your answer.

Answer 3

No, D dominates d in all four boxes

Question 4

Explain the difference between incomplete dominance and codominance.

Answer 4

Incomplete dominance: Traits blend together. NO trait is overly dominate over the other. they blend traits (red and white = pink)

Co- dominance: NO blending. Both traits are equally dominate, so both appear. Brown and white parent cows have a brown and white calf. Both traits are shown

Question 5

The condition where two or more genes work together to produce a certain trait is called

a. a sex-linked trait
b. multiple alleles.
c. incomplete dominance.
d. polygenic inheritance

Answer 5

Polygenic inheritance

Genes must work together

Question 6

How would you represent the genotype for a woman who is hybrid for type A blood?

a. XAi
b. IAi
c. IAIA
d. XAYi

Answer 6

B. IAi

good example of multiple alleles for a single trait in hu- mans is blood types.

IAIA is purebred for A blood
IAi is hubrid for A blood
(i is type O and is recessive)

Question 7

A woman with type O blood marries a man with type AB blood. Is it possible for any of their children to have type O blood? Explain.

Answer 7

No. In order to have type O blood, a person must be purebred recessive (ii); he cannot have either dominant allele.

Question 8

Write the genotypes for a female carrier of red-green colorblindness and a normal male.

Answer 8

?

Question 9

________ ________ is a model used to represent genetic crosses.

Answer 9

Punnett squares

Question 10

This is a grid that is divided into four boxes and uses letters to represent alleles.

Answer 10

Punnett square

Question 11

If TT and tt were used as parents on a Punnett square, all the inside boxes would have the same genotype… What would it be?

What would the phenotype be?

Answer 11

(T, t)

Tall plants

Question 12

This is when two different alleles for the same trait are both expressed, resulting in a blending of the two forms of that trait.

(red and white flowers make pink)

Answer 12

Incomplete dominance

Question 14

A Punnett square can have 4 or more boxes, but What does the number of boxes mean?

Answer 14

Generic possibilities of their offspring

Question 15

True or False: The number of boxes in a Punnett square is equal to the number of offspring the parents had?

Answer 15

False. Its the number of genetic possibilities

Question 16

Make Punnett Squares to find the following:

How many different genotypes of a TT × tt purebred cross?

How many different genotypes for a Tt × Tt hybrid cross?

Answer 16

One (T, t)

Three (T, T), (T, t), (t, t)

Question 17

This Is when there is no pure dominant or pure recessive allele expressed (phenotype)

Answer 17

Incomplete dominance

Question 18

What are the three variations to Mendel’s theories?

Answer 18

Incomplete dominance: red + white = pink

Codominance: Brown + white = brown and white

Polygenic inheritance: multiple genes result in unique trait

Question 19

Give some examples of polygenic inheritance where two or more genes “work together” to make one trait:

Answer 19

Skin color
Hair color
height
intelligence
body type

Question 20

________ _________ are the chromosomes that determine whether an organism is male or female.

Answer 20

Sex chromosomes

Question 21

A normal human has 23 pairs of chromosomes. which one determines the persons sex (gender)?

Answer 21

23

Question 22

What two alleles do female and male sex chromosomes have? same or different?

(Remember, most traits dont matter if the organism is a bot of girl, except for these traits on the sex chromosomes)

Answer 22

XX

XY

Question 23

What determines if a kid will be a boy or girl? The mom’s chromosomes or the fathers chromosomes?

Answer 23

the X or Y chromosome of the father’s sperm determines the sex of the child (50-50’chance)

Question 24

Some inherited traits are controlled by genes located on the sex chromosomes (X or Y). These traits are called ________ ________.

Answer 24

Sex-linked traits

Question 25

The Y chromosome is smaller than the X and has a few genes. Therefore, most sex-linked traits are on which chromosome, X or Y?

Answer 25

X chromosome

If on the X, its not on the smaller Y

Question 26

Its hard to tell the difference between boy and girl chicks. Reginald Punnett discovered that the color of certain feathers is a sex-linked trait.

Answer 26

True. Helped war country only save female chicks to make eggs

Question 27

__________ are people who have the allele for a trait but do not exhibit the trait them- selves.

Answer 27

Carriers

Question 41

Create a Prunnett Square to find out why Juliet has blue eyes:

What are the odds of our next kid having blue eyes (phenotype)?

Answer 41

50-50