🔹 Predicting Inheritance Using Punnett Squares

Question 1

What was Mendel’s first principle relating to inheritance?

Answer 1

The various hereditary characteristics were controlled by factors (genes) that occurred in pairs

Question 2

What was Mendel’s second principle relating to inheritance?

Answer 2

1. During the formation of the gametes (humans’ sperm/eggs), the pairs of factors separate
2. Each gamete receives only one set of factors (genes) with the other set going to another gamete
3. Gametes unite at fertilisation, allowing different combinations of genes to come together.

Question 3

What is a trait?

Answer 3

The characteristics due to the genetic constitution of an individual

Question 4

What is pure-breeding?

Answer 4

The production of the same characteristic in each succeeding generation when individuals are bred among themselves; homozygous

Question 5

What is a progeny?

Answer 5

Offspring

Question 6

What are hybrids?

Answer 6

An offspring that is the result of a mating between individuals of two different genetic constitutions

Question 7

What is a dominant trait?

Answer 7

One of a pair of contrasting characteristics, which is controlled by an allele that is not masked by other alleles

Question 8

What is a recessive trait?

Answer 8

One of a pair of contrasting characteristics, which is controlled by an allele that is masked by dominant alleles

Question 9

What is the principle of segregation?

Answer 9

The principle that the alleles for a trait are separated during the formation of gametes

Question 10

What is a monohybrid cross?

Answer 10

A mating between individuals in which one pair of contrasting characteristics is being considered

Question 11

What is a genotype?

Answer 11

The genetic makeup of an individual as determined by the alleles for the characsteristic being considered

Question 12

What is a phenotype?

Answer 12

The physical appearance of an individual as determined by the expression of the alleles for that characteristic

Question 13

What are alleles?

Answer 13

An alternative form of a gene

Question 14

What does homozygous mean?

Answer 14

The situation where an individual has the same alleles for a particular characteristic (pure-breeding)

Question 15

What does heterozygous mean?

Answer 15

The situation where an individual possesses different alleles for a particular characteristic (hybrid)

Question 16

What is a gene?

Answer 16

The factor that determines an inherited characteristic; located in the chromosome

Question 17

What happens to the gametes that may affect inheritance probabilities?

Answer 17

During formation of gametes by meiosis, pairs of chromosomes separate, with 1 of each pair going to each gamete

Means that pairs of alleles segregate with only 1 allele for a characteristic carried by each gamete.

Question 18

What is a pedigree?

Answer 18

A diagram recording the ancestry of an individual and the traits inherited over several generations

Question 19

What is a Punnett Square?

Answer 19

A grid used to predict the probability of genotypes of offspring