Questions and Answers
What happens at the beginning of interphase?
Cells grow, synthesize mRNA and proteins required for DNA synthesis.
What occurs to DNA in the nucleus during interphase?
DNA is copied and the cell grows some more.
What is necessary for cell growth?
2 DNA sets.
How many chromosomes does a cell have?
Signup and view all the answers
How do chromosomes separate in anaphase I?
Signup and view all the answers
How does anaphase I in meiosis differ from anaphase in mitosis?
Signup and view all the answers
How many chromosomes are on each side at the end of anaphase I (meiosis)?
Signup and view all the answers
What happens to chromosomes during telophase I?
Signup and view all the answers
What is a contractile ring?
Signup and view all the answers
What proteins form the contractile units of skeletal muscle?
Signup and view all the answers
Before prophase II begins, does the cell duplicate itself?
Signup and view all the answers
During metaphase II, do homologous chromosomes pair up as in metaphase I?
Signup and view all the answers
How does anaphase II differ from anaphase I?
Signup and view all the answers
At the end of anaphase II, how many chromatids are on each side?
Signup and view all the answers
After cytokinesis, how many cells are there?
Signup and view all the answers
Are all cells the same size after meiosis?
Signup and view all the answers
Is there any difference between female and male cells after meiosis?
Signup and view all the answers
How do female cells look after cytokinesis?
Signup and view all the answers
What are the sizes of the 4 female cells?
Signup and view all the answers
What is the largest cell called?
Signup and view all the answers
What are the smaller cells called?
Signup and view all the answers
Why are egg cells large and sperm cells small?
Signup and view all the answers
Which color chromosomes pair together?
Signup and view all the answers
List possible chromosome combinations.
Signup and view all the answers
What is a genotype?
Signup and view all the answers
When putting pairs of homologous chromosomes together, what happens?
Signup and view all the answers
What is crossover?
Signup and view all the answers
How do random distribution of chromosomes and crossovers create more variation in the resulting gametes?
Signup and view all the answers
What happens to meiosis without DNA replication?
Signup and view all the answers
Describe what would happen if chromosomes did not attach to spindle fibers during metaphase I.
Signup and view all the answers
Describe what would happen if sister chromatids were not pulled apart at anaphase II.
Signup and view all the answers
Describe what would happen if cytokinesis did not occur.
Signup and view all the answers
Study Notes
Interphase and DNA Synthesis
- Interphase starts with cell growth, synthesis of mRNA, and proteins essential for DNA synthesis.
- During interphase, DNA within the nucleus is copied as the cell continues to grow.
Chromosome Structure and Separation
- Cells require two sets of DNA for proper growth and division.
- Each cell has four pairs of chromosomes that play a crucial role in genetic material distribution.
- In anaphase I, sister chromatids are pulled to opposite ends of the cell.
Differences Between Meiosis and Mitosis
- Mitosis results in the separation of chromatids into four distinct parts; meiosis separates two chromatids.
- Anaphase I involves chromosomes whereas anaphase II concerns sister chromatids.
- At the conclusion of anaphase I in meiosis, there are two chromosomes on each side.
Telophase and Cytokinesis
- In telophase I, chromosomes uncoil and the nuclear envelope reforms around them.
- A contractile ring, made of actin and myosin filaments, forms around the dividing cell to facilitate cytokinesis.
- Post cytokinesis, four new cells are formed, all initially the same size.
Gender and Size of Gametes
- All cells produced are initially similar in size; however, in females, gametes differ in size after cytokinesis (three smaller polar bodies and one larger ovum).
- Egg cells are larger to accommodate the resources necessary for new life, while sperm cells are smaller, focusing on genetic transmission.
Chromosome Pairing and Genetic Variation
- Chromosome pairs consist of specific color combinations (e.g., LG&DP, DG&LP).
- Various combinations of chromosomes can occur during meiosis, leading to genetic diversity.
- During crossover, homologous chromosomes can exchange genetic material, increasing genetic variation among gametes.
Consequences of Errors in Meiosis
- If DNA replication does not occur prior to meiosis, resulting gametes may lack essential genetic material.
- Improper attachment to spindle fibers during metaphase I can lead to unequal chromosome segregation, causing daughter cells with abnormal genetic content.
- Failure to separate sister chromatids during anaphase II can result in both chromatids being retained in the same gamete.
- Absence of cytokinesis leads to cell fusion and can cause polyploidy, a condition where cells possess more than two paired sets of chromosomes.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your understanding of meiosis with these flashcards that cover key concepts such as interphase, DNA replication, and chromosome separation. Perfect for students looking to reinforce their knowledge in cell biology and genetics.
