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Questions and Answers
What are homologous chromosomes?
What are homologous chromosomes?
How many pairs of homologous chromosomes are present in human body cells?
How many pairs of homologous chromosomes are present in human body cells?
Which component of the cell contains the genetic information in the form of chromosomes?
Which component of the cell contains the genetic information in the form of chromosomes?
From which parent do you inherit the ovum, and how many chromosomes does it contain?
From which parent do you inherit the ovum, and how many chromosomes does it contain?
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What process makes chromosomes most visible?
What process makes chromosomes most visible?
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What is the organization of genetic information from larger to smaller components?
What is the organization of genetic information from larger to smaller components?
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Which of the following represents a type of variation in genetics?
Which of the following represents a type of variation in genetics?
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How many total chromosomes are present in human body cells, excluding sex cells?
How many total chromosomes are present in human body cells, excluding sex cells?
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What defines a species?
What defines a species?
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Which of the following is an example of environmental variation?
Which of the following is an example of environmental variation?
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Which pair correctly distinguishes continuous variation from discontinuous variation?
Which pair correctly distinguishes continuous variation from discontinuous variation?
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Which of the following traits exhibits discontinuous variation?
Which of the following traits exhibits discontinuous variation?
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What is the distinction between inherited and environmental characteristics?
What is the distinction between inherited and environmental characteristics?
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Which trait can be considered a form of continuous variation?
Which trait can be considered a form of continuous variation?
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Which of the following traits is NOT a discontinuous variation?
Which of the following traits is NOT a discontinuous variation?
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Which statement correctly describes a characteristic of heterochromia?
Which statement correctly describes a characteristic of heterochromia?
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What are the two types of sex chromosomes present in human beings?
What are the two types of sex chromosomes present in human beings?
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How many chromosomes does a human cell typically have?
How many chromosomes does a human cell typically have?
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From whom does a baby boy inherit his Y chromosome?
From whom does a baby boy inherit his Y chromosome?
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What is the process called through which sex cells are produced?
What is the process called through which sex cells are produced?
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How are chromosomes organized in a karyotype?
How are chromosomes organized in a karyotype?
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Which chromosome pair determines the sex of an individual?
Which chromosome pair determines the sex of an individual?
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What is a chromosomal disorder?
What is a chromosomal disorder?
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What is the total number of chromosomes contributed by a sperm and an egg together?
What is the total number of chromosomes contributed by a sperm and an egg together?
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What is Klinefelter Syndrome characterized by?
What is Klinefelter Syndrome characterized by?
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What do chromosomes primarily contain?
What do chromosomes primarily contain?
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How many chromosomes are present in most human cells?
How many chromosomes are present in most human cells?
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What process forms sex cells from diploid cells?
What process forms sex cells from diploid cells?
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What is the karyotype of a normal female?
What is the karyotype of a normal female?
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What is the chromosomal composition of an individual with Down syndrome?
What is the chromosomal composition of an individual with Down syndrome?
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Why are mules considered infertile?
Why are mules considered infertile?
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Which of the following best defines a karyotype?
Which of the following best defines a karyotype?
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What is the genotype of an individual who expresses the recessive phenotype for blue eye color?
What is the genotype of an individual who expresses the recessive phenotype for blue eye color?
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What is the purpose of a Punnett square?
What is the purpose of a Punnett square?
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If a mother is a carrier for cystic fibrosis (X'X) and the father is normal (XY), what is the likelihood of having a child with cystic fibrosis?
If a mother is a carrier for cystic fibrosis (X'X) and the father is normal (XY), what is the likelihood of having a child with cystic fibrosis?
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How many copies of a recessive allele are required to express a recessive trait?
How many copies of a recessive allele are required to express a recessive trait?
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Which genotype will result in brown eye color?
Which genotype will result in brown eye color?
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What is the phenotype for an individual with the genotype 'BB'?
What is the phenotype for an individual with the genotype 'BB'?
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Why are calico cats predominantly female?
Why are calico cats predominantly female?
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Which of the following statements is true about dominant and recessive alleles?
Which of the following statements is true about dominant and recessive alleles?
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Study Notes
Species
- A group of organisms that can reproduce with one another to produce offspring that can also reproduce.
Variation
- Definition: Differences between individuals of the same species.
- Inherited Variation: Passed on from parents.
- Environmental Variation: Influenced by surroundings.
-
Continuous Variation: Features with a complete range of measurements.
- Examples: Height, weight, wingspan, milk yield in cows
-
Discontinuous Variation: Features that cannot be measured across a complete range.
- Examples: Eye color, male or female, blood group
Inherited vs. Environmental Variation
- Inherited: Characteristics passed from parents.
- Environmental: Characteristics not inherited.
- Many characteristics are a combination of both.
Discontinuous Variation
- Examples:
- Color blindness
- Wet or Dry earwax
- Number of fingers
Continuous Variation Examples
- Height
- Weight
Our Inheritance
- Heterochromia: Difference in melanin distribution
Genes and Chromosomes
- Genes: Units of heredity that determine traits.
-
Chromosomes: Long strands of genetic information located in the nuclei of cells.
- Made of DNA wrapped around proteins.
Genes and Chromosomes: Where do your Genes come from?
- We inherit half of our chromosomes from our mother and half from our father.
Level of Organization in Gene
- Cell
- Nucleus
- Chromosome
- DNA
- Gene
Homologous Chromosomes
- Matching pairs of chromosomes.
- One chromosome from each parent.
Human Chromosomes
- Human body cells (except sex cells) have 46 chromosomes.
- There are 23 pairs of homologous chromosomes.
X and Y Chromosomes
- X Chromosome: Females have two X chromosomes.
- Y Chromosome: Males have one X chromosome and one Y chromosome.
- A baby boy inherits his Y chromosome from his father.
Chromosomal Disorder
- A change in the number or structure of chromosomes.
- Examples:
- Down Syndrome: Extra copy of chromosome 21.
- Turner Syndrome: One of the X chromosomes is missing or partially missing. Affects only females.
- Klinefelter Syndrome: Male born with an extra X chromosome.
Summary (Genes)
- Different variations between humans are due to genes (alleles).
- Long strands inside the nucleus are called chromosomes.
- DNA and proteins make up chromosomes.
- Humans have 46 chromosomes in most cells.
- Sex cells have 23 chromosomes.
- The cell division process to form sex cells is different from other cells: Meiosis and mitosis.
- Chromosomes are chemically stained and categorized digitally from large to small, forming a Karyotype.
Short Summary
- Karyotype: A diagram of a complete set of chromosomes.
- Chromosome: Long strands of genetic information located in the nuclei of cells.
- A person with Down Syndrome has 47 chromosomes.
Why are mules infertile?
- Mules are hybrids resulting from a cross between a horse (64 chromosomes) and a donkey (62 chromosomes). They inherit an uneven number of chromosomes, making them infertile.
Recessive vs Dominant
-
Recessive Allele: Only shows if an individual has two copies of it.
- Example: Blue eye color.
-
Dominant Allele: Always shows, even with one copy.
- Example: Brown eye color.
Punnett Square
- A diagram showing the possible combinations of genes, based on the genes of parents.
- Used to predict the outcome of a particular cross or breeding experiment.
Calico Cats
- Mostly female because the gene for coat color is located on the X chromosome.
- Males only have one X chromosome, so they can't be calico.
Preimplantation genetic screening (PGS)
- A technique used to test embryos for genetic disorders before implantation.
Cystic Fibrosis
- A genetic disorder caused by a recessive allele.
- Affects mostly the lungs, but also the pancreas, liver, kidneys, and intestine.
- If both parents are carriers of the recessive allele, their children have:
- 25% chance of having cystic fibrosis.
- 50% chance of being a healthy carrier.
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Description
This quiz explores the concepts of variation within species, focusing on inherited versus environmental traits. It delves into continuous and discontinuous variation with relevant examples, enhancing your understanding of biological inheritance. Test your knowledge on how these variations affect organisms and populations.