Unit 3: Mitosis and Meiosis
1. Diagram of Mitosis
(You can create a simple drawing showing the stages of mitosis: Prophase, Metaphase, Anaphase, Telophase, and Cytokinesis. Include labels like "Chromosomes", "Spindle fibers", "Nuclear Envelope", etc.)
2. Diagram of Meiosis
(You can create a drawing showing Meiosis I and Meiosis II with stages such as Prophase I, Metaphase I, Anaphase I, Telophase I, Meiosis II stages like Prophase II, Metaphase II, etc. Include labels like "Crossing Over", "Homologous Chromosomes", etc.)
3. T-Chart: Compare and Contrast Mitosis and Meiosis
| Mitosis | Meiosis | |-------------------------------------------|-------------------------------------------| | Produces 2 identical diploid cells | Produces 4 genetically diverse haploid cells | | Occurs in somatic (body) cells | Occurs in gametes (sex cells) | | Consists of 1 division | Consists of 2 divisions | | No crossing over | Crossing over occurs | | Used for growth and repair | Used for sexual reproduction |
4. Define Diploid and Haploid
- Diploid (2n): A diploid cell has two complete sets of chromosomes, one set inherited from each parent. Humans are diploid organisms with 46 chromosomes (23 pairs).
- Haploid (n): A haploid cell has only one set of chromosomes. Gametes (sperm and egg cells) are haploid, having 23 chromosomes.
Word Problems:
- Diploid to Diploid: A parent cell with 46 chromosomes undergoes mitosis. How many chromosomes will each daughter cell have?
- Diploid to Haploid: In a pea plant, a diploid cell with 14 chromosomes undergoes meiosis. How many chromosomes will the resulting gametes have?
- Haploid to Diploid: Two haploid gametes, each with 23 chromosomes, fuse during fertilization. What is the total number of chromosomes in the resulting zygote?
5. Why is crossing over important?
Crossing over is important because it increases genetic diversity in a population. During meiosis, homologous chromosomes exchange segments of genetic material, creating new combinations of genes. This genetic variation can lead to differences in traits, which is crucial for evolution and adaptation to changing environments.
6. Diagram of the Cell Cycle
(You can draw the cell cycle showing G1 phase, S phase, G2 phase, M phase with a description below.)
- G1 Phase: Cell growth and normal functions.
- S Phase: DNA replication occurs, doubling the amount of genetic material.
- G2 Phase: Cell continues to grow and prepares for mitosis.
- M Phase: Mitosis & cytokinesis, where cell division happens.
7. Explanation of Mitosis and Meiosis in Genetic Continuity
Mitosis and meiosis both play essential roles in maintaining genetic continuity within organisms. Mitosis ensures that as somatic cells divide and grow, each new cell receives an identical set of chromosomes, preserving the genetic information. On the other hand, meiosis introduces genetic variation necessary for evolution through the production of haploid gametes. While meiosis creates diversity in offspring that can adapt to environmental changes, mitosis ensures that cellular functions can continue without losing genetic information. Together, they balance stability and variation, which is crucial for the survival of species.
Unit 4: DNA, RNA, DNA Replication, Protein Synthesis
1. Venn Diagram: Compare and Contrast DNA and RNA
(Draw two overlapping circles. One circle for DNA and one for RNA.)
| DNA | | RNA | |-------------------------------------------|--------|-------------------------------------------| | Double-stranded | | Single-stranded | | Contains deoxyribose | | Contains ribose | | A, T, C, G bases | | A, U, C, G bases | | Stores genetic information | | Transmits genetic information |
2. Picture to Represent DNA Replication
(You can draw a simple DNA double helix unwinding, with new complementary strands being formed.)
Importance: DNA replication is crucial because it ensures that each new cell has an identical copy of the DNA when cells divide. This is essential for growth, healing, and reproduction.
Enzymes Involved: The key enzymes include DNA helicase (which unwinds the DNA), DNA polymerase (which adds new nucleotides), and ligase (which joins the Okazaki fragments on the lagging strand).
Semiconservative Explanation: Semiconservative means that during DNA replication, each new double helix consists of one old strand and one new strand. This process helps maintain the integrity of the genetic information.
3. Purpose of Transcription
The purpose of transcription is to convert the genetic information from DNA into messenger RNA (mRNA), which can be used to make proteins. This process takes place in the nucleus of eukaryotic cells.
4. Purpose of Translation
The purpose of translation is to synthesize proteins from the mRNA transcript by using amino acids. This process occurs in the cytoplasm, specifically on ribosomes.
5. Describe the 3 Types of RNA
- mRNA (Messenger RNA): Carries the genetic information from DNA to the ribosome for protein synthesis.
- tRNA (Transfer RNA): Brings the appropriate amino acids to the ribosome during translation.
- rRNA (Ribosomal RNA): Makes up the ribosome, facilitating the translation process.
6. Determine the Sequence of Amino Acids
To determine the sequence of amino acids from the DNA sequence CATGGACGC, we first need to transcribe it into mRNA, changing A to U, T to A, C to G, and G to C.
Original DNA: CAT GGA CGC Transcribed mRNA: GUA CCU GCG
Using the codon chart:
- GUA = Valine (Val)
- CCU = Proline (Pro)
- GCG = Alanine (Ala)
So, the sequence of amino acids is Val-Pro-Ala.
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