chapter 12 study guide Flashcards
How did Gregor Mendel perform cross-pollination in his experiments with pea plants?
Mendel removed the male parts from one plant and added pollen from another plant to cross-pollinate.
Who is considered the father of genetics, and what organism did he use for his experiments
Gregor Mendel is the father of genetics. He used pea plants for his experiments.
What is a gene, and how is it passed from one generation to the next?
A gene is a part of DNA that determines traits. It is passed down from parents to offspring.
What is the difference between homozygous dominant and homozygous recessive?
Homozygous dominant has two dominant alleles (like AA), and homozygous recessive has two recessive alleles (like aa).
Define heterozygous and give an example.
Heterozygous means having two different alleles (like Aa).
What is incomplete dominance? Provide an example of a trait that exhibits incomplete dominance
Incomplete dominance is when neither allele is fully dominant, creating a mix of traits. Example: red + white flowers = pink flowers.
Explain codominance and give an example of a trait that shows codominance.
Codominance happens when both alleles are fully expressed. Example: cattle with both red and white patches.
What is polygenic inheritance, and what are some examples of traits controlled by multiple genes?
Polygenic inheritance is when many genes control a trait. Examples: skin color and height.
What is mitosis, and why is it important?
Mitosis is when a cell divides to make two identical cells. It’s important for growth and repair.
What happens during crossing over in meiosis, and why is it important for genetic diversity?
Crossing over is when chromosomes exchange DNA, making genetic diversity by mixing genes.
What occurs in Metaphase II of meiosis, and how does it resemble Metaphase of mitosis?
In Metaphase II, chromosomes line up in the middle of the cell, just like in mitosis.
What are chromosomes, and how do they carry genetic information?
Chromosomes are structures made of DNA that carry genes, which determine traits.
How many chromosomes do humans have, and how are they inherited?
Humans have 46 chromosomes (23 pairs). One set comes from each parent.
What are homologous chromosomes, and why are they important in inheritance?
Homologous chromosomes are pairs of chromosomes with similar genes, one from each parent. They are important because they carry the same genes but can have different versions of alleles.
What is the difference between diploid and haploid cells?
Diploid cells have two sets of chromosomes (2n), while haploid cells have one set (n). Diploid cells are body cells, and haploid cells are sperm and egg cells.
Explain the concept of nondisjunction and describe its potential consequences for an organism.
Nondisjunction is when chromosomes don’t separate correctly during cell division. This can cause too many or too few chromosomes, leading to genetic disorders.
How does nondisjunction lead to genetic disorders like Down syndrome?
Nondisjunction can cause an extra chromosome 21 in a gamete. If this gamete combines with another, the child will have three copies of chromosome 21, leading to Down syndrome.
what’s the difference between mitosis and meiosis.
mitosis: body cells, 1 division, no cross over, genetically identical cells, 2 diploid.
meiosis: gametes, 4 haploid, 2 division, crossing over, genetically different cells.
