Understanding Chromosomes and Chromatids

Dr. Crowder explains the differences between chromosomes and chromatids, focusing on their roles before and after DNA replication and cell division. The video covers the structure of DNA, chromatin, and nucleosomes, and discusses human chromosomes, including autosomes and sex chromosomes. It also delves into homologous chromosomes, DNA replication, and the formation of chromatids, providing clarity on the terminology used to describe these genetic structures.

What is the basic unit of chromatin?

• Chromatid

• Gene

• Nucleosome

• Chromosome

How many autosomes are present in a human cell?

• 24

• 46

• 23

• 22

What does it mean for humans to be diploid?

• Having two copies of each chromosome

• Having one copy of each chromosome

• Having three copies of each chromosome

• Having four copies of each chromosome

What are homologous chromosomes?

• Chromosomes with the same genes but different alleles

• Chromosomes with identical genes and alleles

• Chromosomes with different genes and alleles

• Chromosomes that are identical in every way

What is a single chromosome composed of?

• Multiple RNA molecules

• A double-stranded DNA molecule

• A protein chain

• A single-stranded DNA molecule

How many unique chromosomes are present in a human somatic cell?

• 22

• 92

• 46

• 23

What is a chromatid?

• A replicated chromosome

• A pair of homologous chromosomes

• A single-stranded DNA molecule

• A double-stranded DNA molecule

What is a pair of sister chromatids?

• Two different chromatids

• Two identical chromatids

• Two homologous chromosomes

• Two identical chromosomes

After DNA replication, how many chromatids are present in a human cell?

• 23

• 92

• 184

• 46

What happens to a cell after it undergoes M phase?

• It becomes tetraploid

• It divides into two diploid cells

• It becomes haploid

• It remains unchanged