14 Questions
What is the function of DNA in cells?
To store and transmit genetic information
What is the main difference between prokaryotic and eukaryotic cells?
The presence of membrane-bound organelles
Where is the DNA located in a prokaryotic cell?
In the cytosol
What is the structure of DNA in prokaryotic cells?
Circular, double-stranded
What is the function of plasmids in prokaryotic cells?
To store genetic information
How many chromosomes are found in human somatic cells?
46
What is a karyotype?
A set of human chromosomes
What are the building blocks of chromosomes?
DNA molecule and histone proteins
What is the primary function of telomeres?
To protect the tips of chromosomes from breakdown
When are chromosomes visible under a light microscope?
During cell division
What is the term for the decondensed form of chromosomes?
Chromatin
Why is it important for chromatin to condense into chromosomes prior to cell division?
To protect the genetic code and ensure identical copies are transferred to both daughter cells
What is unique about the DNA found in mitochondria and chloroplasts?
It is circular and double-stranded
Why is it important for chromatin to be decondensed during the cell cycle?
To make the genetic code accessible for DNA synthesis, protein synthesis, and RNA synthesis
Study Notes
Chromosomes and DNA
- DNA is the structural unit of information in cells, storing and transmitting genetic information and managing cellular activities.
- DNA is universal and functions similarly in all living things, allowing DNA from one species to be inserted into another species' genome.
Prokaryotic Cells
- Prokaryotic cells are unspecialized and lack membrane-bound organelles, characteristic of bacterial cells.
- In prokaryotic cells, DNA is located in the cytosol, known as the nucleoid region, and consists of one circular, double-stranded chromosome.
- Prokaryotic cells also contain RNA, proteins, and plasmids, which are small, circular, double-stranded DNA molecules separate from the chromosomal DNA.
Eukaryotic Cells
- Eukaryotic cells are highly organized, specialized, and characteristic of animals, plants, and fungi.
- They contain membrane-bound organelles, such as the nucleus, mitochondria, chloroplasts, Golgi bodies, and endoplasmic reticulum, each with specific functions.
Chromosomes in Eukaryotic Cells
- Most DNA in eukaryotic cells is found in the nucleus, specifically in 46 chromosomes organized into 23 pairs (22 autosomal and 1 sex chromosome).
- Chromosomes are condensed linear strands of DNA and histone proteins, with telomeres at the ends to protect against breakdown and fusion.
- Chromosomes are only visible under a light microscope during cell division when DNA is tightly coiled around histone proteins (condensed).
Chromatin
- Chromatin is the decondensed form of chromosomes, present in the nucleus throughout the cell cycle (excluding cell division).
- Chromatin is essential for DNA synthesis, protein synthesis, and RNA synthesis, as it makes the genetic code accessible.
Mitochondrial and Chloroplast DNA
- Mitochondria (mtDNA) and chloroplasts (cpDNA) are eukaryotic membrane-bound organelles that contain double-stranded, circular DNA molecules.
This quiz covers the basics of chromosomes and DNA, including their structure and function in prokaryotic cells. Learn about the storage and transmission of genetic information and how DNA works in different species.
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