Question

what type of inheritance is shown in the pedigree? (pedigree image) \bigcirc a sex linked dominant \bigcirc b autosomal dominant \bigcirc c sex linked recessive \bigcirc d autosomal recessive \
question 11 \
how many chromosome pairs are shown in a normal human karyotype? \bigcirc a 2 \bigcirc b 23 \bigcirc c 44 \bigcirc d 46

Explanation:

First Question (Inheritance Type)

To determine the inheritance type:

• Autosomal dominant traits often appear in every generation, affect both sexes equally, and a parent with the trait (dominant allele) has a high chance of passing it on. In the pedigree, affected individuals (filled symbols) are present across generations, and both males and females are affected (e.g., I-1 (male) passes to II-1, II-5, II-8; II-8 (female) passes to III-6, III-8).
• Sex - linked dominant would show sex - biased inheritance (e.g., more males or females affected in a pattern related to X/Y chromosomes), which is not seen here.
• Sex - linked recessive often has more males affected (since males have one X), and carriers (females with one recessive allele) are common, but this pedigree has equal male - female affected and no carrier - like patterns.
• Autosomal recessive usually has affected individuals with unaffected parents (carriers), but here affected individuals have affected or affected - and - unaffected parents, not the typical recessive pattern. So the inheritance is autosomal dominant.

A normal human karyotype has 22 pairs of autosomal chromosomes and 1 pair of sex chromosomes, totaling 23 pairs of chromosomes. Option a (2) is too few, option c (44) is the number of autosomal chromosomes (not pairs), and option d (46) is the total number of chromosomes (not pairs). So the number of chromosome pairs is 23.

Answer:

b. autosomal dominant

Second Question (Chromosome Pairs in Human Karyotype)