Genetics: Alleles and Chromosomes

The video tutorial explains the differences between alleles and chromosomes, focusing on dominant and recessive alleles. It begins with an introduction to cell structure and chromosomes, followed by a detailed explanation of karyotypes and homologous chromosomes. The concept of alleles is explored, highlighting genetic variation through homozygous and heterozygous conditions. The tutorial concludes with an understanding of dominant and recessive alleles, using examples like eye color to illustrate these genetic principles.

What is the most condensed form of genetic material visible during metaphase?

• Gene

• Chromosome

• Nucleus

• Allele

How many chromosomes are present in a typical human male karyotype?

• 44

• 23

• 46

• 22 pairs plus XY

What are homologous chromosomes?

• Chromosomes with the same gene position and centromeric position

• Chromosomes that are always identical

• Chromosomes with different lengths

• Chromosomes that do not pair during meiosis

What is an allele?

• A segment of DNA that codes for a protein

• A different version of a gene

• A type of cell

• A type of chromosome

What does it mean if an organism is homozygous for a trait?

• It has no alleles for a trait

• It has more than two alleles for a trait

• It has two identical alleles for a trait

• It has two different alleles for a trait

In a diploid organism, how many alleles can a single trait have?

• One

• Two

• Four

• Three

What is a dominant allele?

• An allele that never expresses

• An allele that can express with just one copy

• An allele that is always recessive

• An allele that requires two copies to express

In the context of eye color, which allele is considered dominant?

• Green eye allele

• Brown eye allele

• Blue eye allele

• Hazel eye allele

What is required for a recessive allele to express its trait?

• Three copies of the allele

• No copies of the allele

• One copy of the allele

• Two copies of the allele

What is the main takeaway about dominant and recessive alleles?

• Recessive alleles can express with one copy

• Dominant alleles can express with one copy, while recessive alleles need two

• Dominant alleles require two copies to express

• Recessive alleles are always expressed