lab 1: mendelian genetics

Question 1

gene

Answer 1

-a hereditary factor that influences a particular trait
-portions of DNA that have the ability to code for a trait

Question 2

allele

Answer 2

a version of a gene

Question 3

locus

Answer 3

specific position on a chromosome where a particular gene is located

Question 4

gametes

Answer 4

sex cells (sperm & egg)

Question 5

genotype

Answer 5

a listing of the alleles in an individual (RR) (Rr) (rr)

Question 6

phenotype

Answer 6

an individual’s observable traits

Question 7

homozygous

Answer 7

having 2 of the same alleles (RR) (rr)

Question 8

heterozygous

Answer 8

having 2 different alleles (Rr)

Question 9

dominant allele

Answer 9

-an allele that is fully expressed in the phenotype of a heterozygote
-will always mask recessive alleles

Question 10

recessive allele

Answer 10

-an allele that is masked when a dominant allele is present
-only expressed in homozygotes

Question 11

pure line

Answer 11

individuals of the same phenotype that, when crossed, always produce offspring with the same phenotype

Question 12

hybrid

Answer 12

offspring of crosses between parents with different traits

Question 13

polygenetic traits

Answer 13

many genes coding for one trait

Question 14

particulate theory of inheritance

Answer 14

-genes that govern traits are inherited as discrete units that remain unchanged as they are passed from parent to offspring
-asserted that genes are located on chromosomes

Question 15

law of segregation (Mendel’s first law)

Answer 15

-the 2 alleles of a given gene segregates into separate gametes
-each gamete has an equal chance of possessing either member of a pair of homologous chromosomes
-when joined in fertilization they combine to produce a phenotype based on the rules of dominance
-gametes combine randomly

Question 16

law of independent assortment (Mendel’s second law)

Answer 16

-genes on non-homologous or different chromosomes will be distributed randomly into gametes
-increases genetic variation

Question 17

what is the difference between Mendel’s 1st & 2nd law?

Answer 17

the key difference is that the 1st law describes the segregation of the alleles of a given locus into separate gametes during gametogenesis while the 2nd law describes the independent transmission of alleles of genes into daughter cells without the influence of each other

Question 18

what was Mendel’s experimental method?

Answer 18

-he removed the anther (male part) then dusted the stigma (female part) with pollen from the white plant
-the resulting seeds were planted & grew

Question 19

what is the p generation?

Answer 19

original parent generation (true breeding parents)

Question 20

what is the F1 generation?

Answer 20

generation after parents (all were purple heterozygotes in Mendel’s experiments)

Question 21

what is the F2 generation?

Answer 21

generation after F1 (Mendel let them self fertilize & they had a 3:1 ratio)

Question 22

what is the phenotypic ratio for a monohybrid cross?

Answer 22

3:1

Question 23

what is the phenotypic ratio for a dihybrid cross?

Answer 23

9:3:3:1

Question 24

simple dominance

Answer 24

-the dominant one masks recessive when present
-the recessive one only can be expressed when both copies present are recessive

Question 25

incomplete dominance

Answer 25

-a pattern of inheritance in which 2 alleles, inherited from the parents, are neither dominant nor recessive -the resulting offspring have a phenotype that is a blending of the parental traits -ex: if a red & white flower are breed together then it creates a pink one

Question 26

codominance

Answer 26

-a condition in which both alleles for a gene are fully expressed -ex: if a pink & white flower was breed together, then the new flower is pink & white

Question 27

codominance example in blood types

Answer 27

type AB is a popular example since both A & B are dominant while type O is recessive

Question 28

what is the genotype of blood types?

Answer 28

-type A (I^A I^A) or (I^A i) -type B (I^B I^B) or (I^B i) -type AB (I^A I^B) -type O (ii)

Question 29

what determines your blood type?

Answer 29

-the proteins called antigens are on the surface of all the red blood cells (if you have type A you have A antigens, type B has B antigens, type AB has both A & B antigens, & type O wouldn’t have any antigens)

Question 30

what antibodies would the blood types have?

Answer 30

-the antibody against the antigen it doesn’t carry -type A: b antibodies -type B: a antibodies -type AB: none -type O: a & B antibodies

Question 31

which blood type is the universal donor? a universal acceptor?

Answer 31

-type O = universal donor -type O can only receive type O -type AB is the universal acceptor

Question 32

how can we determine which blood type it is?

Answer 32

-to determine a person’s blood type, we add serums to blood samples & see if clumps form -agglutination (clumping) occurs when blood cells stick & clumps together, when donor blood cells are incompatible with recipient serum

Question 33

how to understand which blood type it is based on the serum?

Answer 33

-will react positively if their type is in the serum = no clumps -will react negatively if their type is not in the serum = clumps

Question 34

how do we know if a blood type is positive or negative?

Answer 34

-if you have positive, then you have the protein Rh on the surface of the blood cells -if you have negative, then you do not have the Rh protein

Question 35

pedigrees (won’t be tested on but cool to know ig)

Answer 35

-a consistent graphical presentation of matings & offspring over multiple generations for a particular trait -family histories -disease trait: dominant or recessive? -symbols: male = square, female = circle, affected = full, carriers = half filled in