Galactosemia: Autosomal Recessive Disease

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Questions and Answers

In a heterozygote (+/M) with haploinsufficient genes, which allele is considered dominant?

Both alleles are equally dominant

Wild-type allele (+)

Neither allele exhibits dominance

Mutated allele (M) (correct)

What is the expected phenotypic ratio of purple to white flowers in the second filial generation from a monohybrid cross of a pure purple flower and a pure white flower?

1:1

2:1

3:1 (correct)

4:0

According to Mendel's first law of equal segregation, what is true about gametes?

Gametes can carry two alleles of a gene pair

All gametes carry the dominant allele

Half of gametes carry one allele of a gene pair (correct)

Gametes are formed by the random fusion of homologous chromosomes

What does the term phenotype refer to in genetics?

The observable characteristics of an organism Signup and view all the answers

What is represented by 'A/a;B/b' in comparison to 'Ab/aB' and 'AB/ab'?

Genes on homologous chromosomes in heterozygous form Signup and view all the answers

Which of the following describes incomplete dominance?

Heterozygous individuals display intermediate phenotypes between homozygous types. Signup and view all the answers

What does the presence of one dominant allele indicate in the context of mutation?

The mutation can be dominant, leading to a gain of function. Signup and view all the answers

How is codominance defined?

Both alleles are detectable and expressed in heterozygotes. Signup and view all the answers

Which blood type is associated with the genotype i/i?

Type O Signup and view all the answers

Which of the following statements about ABO blood types is true?

IA and IB are codominant with each other. Signup and view all the answers

What characterizes a loss of function mutation?

It results in a complete absence of function. Signup and view all the answers

What must be true for a mutation to be considered recessive?

The gene must be functionally haplosufficient. Signup and view all the answers

What is the minimum number of units required to produce either the wild-type or mutant phenotype in a scenario involving codominance?

10 units Signup and view all the answers

What is a characteristic of non-sister chromatids?

They can be either identical or different. Signup and view all the answers

What concept was proposed by Sutton and Boveri regarding Mendel’s 'particles'?

They are associated with chromosomes. Signup and view all the answers

What defines a homogametic sex in humans?

Having a matching pair of sex chromosomes. Signup and view all the answers

Which of the following is a key feature of a reciprocal cross?

It provides information about potential sex linkage. Signup and view all the answers

In autosomal recessive pedigrees, which of the following is true?

The trait can appear in offspring from unaffected parents. Signup and view all the answers

What is indicated by the absence of skipping generations in an autosomal dominant pedigree?

Each affected individual must have at least one affected parent. Signup and view all the answers

What does pedigree analysis primarily allow geneticists to do?

Track inheritance patterns through family trees. Signup and view all the answers

Which of the following conclusions can be drawn from an autosomal dominant trait pedigree?

Both males and females can transmit the trait equally. Signup and view all the answers

What does the genotype G/g represent in a Punnett Square cross?

Heterozygous yellow phenotype Signup and view all the answers

What is indicated by performing a test cross?

To determine the genotype of an individual with a dominant phenotype Signup and view all the answers

Which of the following best describes Mendel’s Law of Equal Segregation?

The alleles segregate equally into gametes during meiosis Signup and view all the answers

In a diploid organism, how is the ploidy number denoted?

n for haploid, 2n for diploid Signup and view all the answers

Which statement is true regarding sister chromatids?

They contain identical genetic information Signup and view all the answers

In the case of an autosomal recessive disease like galactosemia, which of the following statements is true?

Two affected parents can produce unaffected children. Signup and view all the answers

What is a notable difference between polymorphisms and rare diseases?

Polymorphisms have a higher frequency compared to rare diseases. Signup and view all the answers

In X-linked recessive inheritance, what is the consequence if a father is affected?

No offspring will be affected if the mother is not a carrier. Signup and view all the answers

If a woman is heterozygous for an X-linked dominant disease, what is the likelihood that she will pass the affected allele to her offspring?

50% for both male and female offspring. Signup and view all the answers

Considering two parents where one has a rare conditions and the other is a known carrier, what is a possible outcome for their children?

Some children will be affected and others will be carriers. Signup and view all the answers

What is the main reason that individuals affected by rare diseases are assumed not to have carriers in their family unless indicated otherwise?

The rarity of the disease suggests few carriers exist. Signup and view all the answers

In the described scenario about a man whose paternal grandfather has galactosemia, what is the inheritance pattern of this condition?

It follows a recessive inheritance pattern. Signup and view all the answers

If both parents are carriers of a recessive disorder, what is the probability of their child being affected?

25% Signup and view all the answers

Study Notes

Autosomal Recessive Disease - Galactosemia

Galactosemia is a rare, autosomal recessive disorder.
The disease is caused by the inability to process galactose, a simple sugar.
Individuals with galactosemia experience muscle, nerve, and kidney malfunction.
The man's paternal grandfather is affected, indicating the man's father is a carrier.
The woman's sister is affected, indicating the woman's mother is likely a carrier.
Since the man is a carrier and the woman has a 50% chance of being a carrier, the probability of their first child having galactosemia is 1/8.
If their first child does have the disease, the probability of their second child having it is 1/4.

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Description

This quiz explores the genetic aspects of galactosemia, an autosomal recessive disorder. It covers the disease's inheritance patterns, carrier probabilities, and implications for affected individuals. Test your understanding of this rare genetic disorder and its impact on families.