Download Human Body in Action ANSWER KEY - Genes and

Genes and Heredity – Answer Sheet
1. Babies are called OFFSPRING.
2. Traits passed from parents are called INHERITED traits.
3. Human body cells contain 46 INDIVIDUAL or 23 PAIR (#) chromosomes.
4. Traits you can see are called the PHENTOYPE.
5. The GENOTYPE is the total genetic makeup of an organism.
6. TRUE: Genes are inherited in pairs. (one set from each parent)
7. The stronger gene is called DOMINANT the other half is RECESSIVE.
8. If both genes are the same, the offspring are called PUREBRED (HOMOZYGOUS).
9. If the genes are different the offspring are called HYBRID or (HETEROZYGOUS).
10. FALSE: The number of chromosomes determines how big an organism is.
11. A PUNNETT square is a diagram that shows the possible combinations of genes
for a particular trait.
12. DNA is the abbreviation for deoxyribonucleic acid.
13. FALSE: The gametes contain the same number of chromosomes as all the other
cells. (They contain half the number of chromosomes…or 23 individual
chromosomes.)
14. AMINO ACIDS are the building blocks for proteins.
15. A change in the DNA is called a MUTATION.
16. FALSE: All mutations are harmful. (Some can be beneficial.)
Reflection Questions:
How can a baby dog end up with its mother’s ears and its father’s hair color?
ORGANSISM INHERIT THEIR TRAITS FROM THEIR PARENTS. THIS IS KNOWN
AS INHERITED TRAITS. IF THE TRAIT IS A DOMINANT TRAIT, IT WILL BE
EXPRESSED IN THE PHYSICAL APPEARANCE OF THE OFFSPRING. IF IT IS A
RECESSIVE TRAIT, IT MUST BE PAIRED WITH ANOTHER RECESSIVE TRAIT IF
IT WILL BE EXPRESSED IN THE OFFSPING.
Who is considered the ‘Father of Genetics’? With what did he experiment?
GREGOR MEDNEL IS CONSIDERED THE FATHER OF GENETICS. HE
EXPERIMENTED WITH PEA PLANTS BECAUSE THEY REPRODUCED AND
DEVELOPED QUICKLY AS WELL HAD MANY OBSERVABLE TRAITS SUCH AS
HEIGHT, PEA COLOR AND PEA SHAPE.
In evening primrose flowers, the color red is dominant to the color white. Using the
letter “R” for the dominant color, use a Punnett square to show a cross between a
homozygous red flower and a heterozygous red flower.
R
r
R = RED; DOMINANT COLOR
r = WHITE; RECESSIVE COLOR
R RR
Rr
R RR
Rr
GENEOTYPE FOR HOMOZYGOUS (same) RED FLOWER = RR
GENOTYPE FOR HETEROZYGOUS (different) RED FLOWER = Rr
List the genotypes of the offspring: RR , RR , Rr , Rr
What will each genotype look like? red, red, red, red