EXAM 2 Flashcards
(41 cards)
What are the stages of the cell cycle, and what is the function of each stage?
G1 (cell growth), S (DNA replication), G2 (preparation for mitosis), and M phase (mitosis).
How does DNA replication occur?
DNA replication is semi-conservative
meaning each new DNA molecule has one old strand and one new strand
what is base pairing?
Base pairing involves A-T and G-C pairing to create a complementary strand
Define chromosome.
A chromosome is a DNA molecule with genetic material
Define gene.
A DNA sequence coding for a trait
Define allele.
An allele is a gene variant
Define DNA
a molecule that contains the genetic code that is unique to every individual
Define genome.
The genome is all genetic material
Define sister chromatids.
sister chromatids are duplicated chromosomes
Define homologous pairs.
homologous pairs are chromosome pairs from each parent
What is the difference between autosomes and sex chromosomes?
Autosomes are non-sex chromosomes (22 pairs in humans), while sex chromosomes determine gender (XX or XY)
What is mitosis, and which cells undergo it?
Mitosis is cell division that produces identical daughter cells, occurring in somatic (body) cells for growth and repair
Name three ways mutations are introduced into DNA.
- DNA replication errors
- Environmental factors (e.g., UV radiation),
- Chemicals (mutagens).
What are three types of mutations?
- Substitution (base change)
- Insertion (extra base added)
- Deletion (base removed)
What are potential consequences of a mutation?
- nonfunctional proteins
- genetic disorders
- beneficial changes, affecting cell functions
How do cell cycle checkpoints prevent most cells from becoming cancerous?
Checkpoints verify DNA integrity
verify proper cell function. Damaged cells are stopped from dividing, preventing mutations from passing on.
Why do tumor cells display unique characteristics?
Tumor cells bypass checkpoints
divide uncontrollably
can obtain mutations that enable rapid growth and spread
What role does meiosis play in the human life cycle?
Meiosis produces gametes (sperm and eggs)
splits chromosome number for sexual reproduction and genetic diversity
What is the structure and role of homologous chromosomes in meiosis?
Homologous chromosomes pair up during meiosis, each containing different alleles. They allow for genetic variation through crossing over
How does crossing over occur, and why is it important?
Crossing over is the exchange of genetic material between homologous chromosomes, increasing genetic diversity
Describe random assortment in meiosis and its result
Random assortment is the independent separation of chromosomes, leading to varied genetic combinations in gametes
What are the differences between mitosis and meiosis?
Mitosis creates identical cells, while meiosis creates genetically unique gametes.
Meiosis includes two divisions, reducing chromosome number
Describe complete dominance with examples.
Complete dominance shows one trait (e.g., brown eyes)
Define incomplete dominance with examples
incomplete dominance blends traits (e.g., pink flowers from red and white parents).
