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Questions and Answers
How many chromosomes are present after meiosis II?
How many chromosomes are present after meiosis II?
The chromosome count remains the same throughout the stages of mitosis.
The chromosome count remains the same throughout the stages of mitosis.
True
What is the total number of chromatids at the end of interphase during meiosis?
What is the total number of chromatids at the end of interphase during meiosis?
92
After DNA replication, the number of chromatids in meiosis is _____.
After DNA replication, the number of chromatids in meiosis is _____.
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Match the following stages of meiosis with their respective chromosome counts:
Match the following stages of meiosis with their respective chromosome counts:
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Which stage of meiosis results in the reduction of chromosome number?
Which stage of meiosis results in the reduction of chromosome number?
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Mitosis results in four daughter cells, while meiosis results in two daughter cells.
Mitosis results in four daughter cells, while meiosis results in two daughter cells.
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What is the key difference in chromosome number between after meiosis I and after meiosis II?
What is the key difference in chromosome number between after meiosis I and after meiosis II?
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What does allele E code for?
What does allele E code for?
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Allele 'a' is responsible for coding red eyes.
Allele 'a' is responsible for coding red eyes.
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What is the process called when the positions of alleles are switched during meiosis?
What is the process called when the positions of alleles are switched during meiosis?
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The alleles E and A code for _____ antennae and _____ eyes.
The alleles E and A code for _____ antennae and _____ eyes.
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Match the allele combinations with their corresponding phenotypes:
Match the allele combinations with their corresponding phenotypes:
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What is independent assortment during meiosis?
What is independent assortment during meiosis?
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Crossing over leads to genetically identical gametes.
Crossing over leads to genetically identical gametes.
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How many different types of gametes are formed from the two loci mentioned?
How many different types of gametes are formed from the two loci mentioned?
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During metaphase I, homologous chromosomes line up on the _____ of the spindle.
During metaphase I, homologous chromosomes line up on the _____ of the spindle.
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Which alleles code for short antennae?
Which alleles code for short antennae?
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What is the main purpose of bracketing linkage groups in a genetic diagram?
What is the main purpose of bracketing linkage groups in a genetic diagram?
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If two genes are linked, offspring ratios will be similar to those when genes are not linked.
If two genes are linked, offspring ratios will be similar to those when genes are not linked.
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What are the genotypes of the plants that produced the heterozygous plants in the given genetic scenario?
What are the genotypes of the plants that produced the heterozygous plants in the given genetic scenario?
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In mice, gene A produces _____ distribution of melanin in fur.
In mice, gene A produces _____ distribution of melanin in fur.
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Match the genotypes with their corresponding phenotype outcomes in mice:
Match the genotypes with their corresponding phenotype outcomes in mice:
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Which scenario describes recessive epistasis in coat color in Labrador retrievers?
Which scenario describes recessive epistasis in coat color in Labrador retrievers?
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If a white mouse is crossed with a pure-breeding black mouse (aaBB), the expected offspring from a mouse with genotype Aabb are _____ agouti and _____ black.
If a white mouse is crossed with a pure-breeding black mouse (aaBB), the expected offspring from a mouse with genotype Aabb are _____ agouti and _____ black.
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What offspring ratio is expected when crossing a white mouse with the genotype Aabb?
What offspring ratio is expected when crossing a white mouse with the genotype Aabb?
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What is the role of transcription factors in gene expression?
What is the role of transcription factors in gene expression?
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Transcription factors can only increase the rate of transcription.
Transcription factors can only increase the rate of transcription.
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What does the transcription factor PIF bind to in order to enable the production of amylase?
What does the transcription factor PIF bind to in order to enable the production of amylase?
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When gibberellin is present, it activates an enzyme that breaks down the ____ protein.
When gibberellin is present, it activates an enzyme that breaks down the ____ protein.
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Match the following terms with their descriptions:
Match the following terms with their descriptions:
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What is the primary genetic cause of sickle cell anaemia?
What is the primary genetic cause of sickle cell anaemia?
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Individuals with sickle cell anaemia always produce only sickle cell haemoglobin.
Individuals with sickle cell anaemia always produce only sickle cell haemoglobin.
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What amino acid is replaced by valine in the abnormal β-globin polypeptide?
What amino acid is replaced by valine in the abnormal β-globin polypeptide?
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The F8 gene codes for factor _____, which is crucial for blood clotting.
The F8 gene codes for factor _____, which is crucial for blood clotting.
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Match the following components with their functions:
Match the following components with their functions:
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What symptom is commonly associated with sickle cell anaemia?
What symptom is commonly associated with sickle cell anaemia?
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A heterozygous individual for the HBB gene will definitely show symptoms of sickle cell anaemia.
A heterozygous individual for the HBB gene will definitely show symptoms of sickle cell anaemia.
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What mutation in the HBB gene results in the change of amino acids in the β-globin chain?
What mutation in the HBB gene results in the change of amino acids in the β-globin chain?
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Study Notes
Meiosis and Chromosome Number
- During meiosis, the number of chromosomes is halved.
- Before interphase, a cell has 46 chromosomes and 46 chromatids.
- After interphase (DNA replication), a cell has 46 chromosomes and 92 chromatids.
- After meiosis I, a cell has 23 chromosomes and 46 chromatids.
- After meiosis II, a cell has 23 chromosomes and 23 chromatids.
Crossing Over
- During meiosis, crossing over can occur between homologous chromosomes, switching the position of alleles.
- Crossing over produces new combinations of alleles.
Independent Assortment
- The random alignment of homologous chromosomes during metaphase I of meiosis produces different combinations of alleles.
- Independent assortment contributes to genetic variation by creating different combinations of alleles in gametes.
Epistasis
- Epistasis refers to the interaction of different genes which can influence phenotypic expression.
- For example, in mice, two genes can affect fur colour: the gene for melanin distribution and the gene for melanin presence.
Sickle Cell Anaemia
- The HBB gene codes for beta-globin, a polypeptide found in haemoglobin.
- Sickle cell anaemia results from a mutation in the HBB gene leading to an abnormal amino acid sequence in beta-globin.
- This abnormal beta-globin alters the shape of red blood cells, causing them to sickle and become inflexible.
- Individuals with sickle cell anaemia experience symptoms like frequent infections, episodes of pain, and anaemia.
Haemophilia
- The F8 gene codes for factor VIII, a clotting factor crucial for blood clotting.
- Mutations in the F8 gene can lead to either reduced or abnormal factor VIII production, causing haemophilia.
Transcription Factors
- Transcription factors are proteins that bind to DNA and regulate gene expression by increasing or decreasing transcription rates.
- Transcription factors can bind to the promoter region of a gene to either allow or prevent transcription.
- For example, the production of amylase in germinating seeds is regulated by the transcription factor PIF.
- This regulation is affected by gibberellin, a plant hormone, which binds to a receptor and activates an enzyme. This enzyme breaks down a protein called DELLA, allowing PIF to bind to the promoter region of the amylase gene, initiating the production of amylase.
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Description
Test your knowledge about meiosis, chromosome number, and genetic variation. This quiz covers key concepts such as crossing over, independent assortment, and epistasis. Perfect for biology students looking to deepen their understanding of these important genetic processes.
