GENETICS

Question 1

TRUE OR FALSE
A PHENOTYPE REPRESENTS A CHARACTERISTIC TRAIT THAT IS OBSERVABLE + IS THE EXPRESSION OF A GENOTYPE?

Answer 1

TRUE.

GENOTYPE IS REFFERING TO THE GENETIC MAKEUP IT IS NOT OBSERVABLE.

PHENOTYPE IS THE OBSERVABLE EXPRESSION OF THE GENOTYPE.

EX: GENOTYPE = H H (SMALLER CAPITOL H)
PHENOTYPE: = BROWN HAIR

Question 2

TRUE OR FALSE
DOMINANT ALLELES ARE REPRESENTED WITH AN UPPERCASE LETTER

Answer 2

TRUE
DOMINANT ALLELES ARE REPRESENTED WITH CAPITOL LETTERS WHILE RECESSIVE ALLELES ARE REPRESENTED WITH LOWER CASE LETTERS

Question 3

CHOOSE THE ALLELE COMBINATION THAT IS HOMOZYGOUS RECESSIVE?

Answer 3

aa
“aa” IS RECESSIVE B/C IT IS LOWERCASE + IT IS HOMOZYGOUS B/C BOTH ALLELES ARE LOWERCASE

Question 4

CHOOSE THE ALLELE COMBINATION THAT IS HETEROZYGOUS?

Answer 4

Aa
“Aa’ IS HETEROZYGOUS B/C IT IS A COMBINATION OF A CAPTIOL LETTER + A LOWERCASE LETTER

Question 5

CHOOSE THE ALLELE COMBINATION THAT IS HOMOZYGOUS DOMINANT?

Answer 5

AA

“AA” IS HOMOZYGOUS B/C BOTH ALLELES ARE “THE SAME” (THEY ARE BOTH CAPITALIZED) + IT IS DOMINANT B/C THERE IS AT LEAST ONE DOMINANT ALLELE PRESENT (REPRESENTED BY THE CAPITAL LETTER)

Question 6

TRUE OR FALSE
WHENEVER A DOMINANT ALLELE IS PRESENT , THE RECESSIVE ALLELE WILL BE MASKED - IT WILL NOT MANIFEST

Answer 6

TRUE

Question 7

HINT: WHENEVER YOU SEE A CAPITOL LETTER REPRESENTING THE DOMINANT ALLELE PRESENT, THAT CHARACTERISTIC TRAIT WILL BE MANIFESTED +THE RECESSIVE WILL BE MASKED

Answer 7

EXAMPLE:
HH= DOMINANT TRAIT WILL MANIFEST

Hh= DOMINANT TRAIT WILL MANIFEST

hh= RECESSIVE TRAIT WILL MANIFEST

Question 8

TRUE OR FALSE

IN INOCMPLETE DOMINANCE THE DOMINANT ALLELE ISN’T FULLY EXPRESSED

Answer 8

TRUE

THIS REFLECTS ONE OF THE NON-MENDELIAN LAWS, THESE LAWS ARE NOT TRADITIONAL

TRADITIONALLY IF A DOMINANT ALLELE IS PRESENT IT WILL COMPLETELY BE “EXPRESSED.’

HOWEVER IN INCOMPLETE DOMINANCE THE DOMINANT ALLELE IS NOT FULLY EXPRESSED

THE MOST IMPORTANT THING TO REMEMBER HERE…
THE OFFSPRING HAS A BLEND OF THE RECESSIVE + DOMINANT TRAIT

EX:

RED FLOWER= DOMINANT
BLUE FLOWER= RECESSIVE
WHEN THEY ARE COMBINED IN INCOMPLETE DOMINANCE THE RESULT IS A BLEN OF BOTH BLUE +RED (PURPLE)

Question 9

TRUE OR FALSE

IN CO-DOMINANCE, BOTH ALLELES ARE FULLY EXPRESSED

Answer 9

TRUE.

CO-DOMINANCE IS A NON -MENDALIAN LAW. IN CO-DOMINANCE THE OFFSPRING WILL EXPRESS BOTH THE DOMINANT + RECESSIVE TRAITS.

EXAMPLE:

ONE FISH IS FULL BLUE+ THE OTHER IS FULLY YELLOW

THE OFFSPRING OF THESE TWO WILL HAVE PARTS THAT ARE FULLY YELLOW + PARTS THAT ARE FULLY BLUE

KEEP IN MIND THIS IS NOT A BLEND, LIKE IN INCOMPLETE DOMINANCE

Question 10

WHICH OF THE FOLLOWING ARE TRUE REGARDING MENDELS LAW OF HEREDITARY?

Answer 10

THE LAW OF DOMINANCE STATES THAT:

-DOMINANT ALLELES MASK RECESSIVE ALLELES THUS MAKING THE DOMINANT ALLELE EXPRESSED

• THE LAW OF SEGREGATION STATES THAT, ALLELES ARE SEPERATED IN A WAY THAT GAMETE CARRIES ONLY ONE ALLELE FOR EACH GENE
• THE LAW OF INDEPENDENT ASSORTMENT STATES ALLELES DO NOT INFLUENCE EACH OTHER WHEN THEY SEGREGATE INTO GAMETES + EACH COMB OF DIFFRENT ALLELES IS EQUALLY LIKELY.