Cell Structures and Organisation of Cells
What is a common function of ribosomes in a cell?
Ribosomes are responsible for protein synthesis.
What is a mitotic index and why is it important?
The mitotic index is the ratio of dividing cells to the total number of cells, indicating the growth rate of a tissue.
How can society use scientific knowledge about stem cells in medical therapies?
Stem cells can be used in regenerative medicine and therapies for diseases such as leukemia and spinal cord injuries.
Name 2 organelles that can be seen in an electron microscope image of a eukaryotic cell.
Organelle examples include the nucleus, mitochondria, Golgi apparatus, and endoplasmic reticulum.
How does the process of crossing over during meiosis contribute to genetic diversity?
Crossing over allows for the exchange of genetic material between homologous chromosomes, creating new allele combinations.
What is the role of epigenetic modification in gene expression?
Epigenetic modifications can alter gene activation without changing the DNA sequence, influencing cell functions.
Name two common features of prokaryotic cells.
Prokaryotic cells have a cell wall and circular DNA.
What is the role of mitosis in asexual reproduction?
Mitosis produces genetically identical daughter cells, allowing for growth and tissue repair in asexual organisms.
Define pluripotent stem cells and provide an example.
Pluripotent stem cells can differentiate into almost any cell type; an example is embryonic stem cells.
Describe the role of the Golgi apparatus in protein transport.
The Golgi apparatus modifies, sorts, and packages proteins for secretion or use within the cell.
What is the significance of meiosis in genetic variation?
Meiosis produces non-identical gametes through independent assortment and crossing over, contributing to genetic diversity in offspring.
How does differential gene expression lead to cell specialization?
Differential gene expression results in cells producing specific proteins that determine their function and structure.
What is the function of mitochondria in a eukaryotic cell?
Mitochondria are the powerhouses of the cell, producing ATP through cellular respiration.
Explain the process of fertilization in mammals.
Fertilization involves the acrosome reaction, where sperm penetrate the egg's zona pellucida, followed by cortical reaction and fusion of nuclei.
What are the characteristics of totipotent stem cells?
Totipotent stem cells can develop into any cell type, including extra-embryonic tissues, and are found in the earliest stages of development.