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Questions and Answers
In a scenario where both parents have black fur (dominant trait), but their kitten is white (recessive trait), what does this indicate about the parents' genotypes?
In a scenario where both parents have black fur (dominant trait), but their kitten is white (recessive trait), what does this indicate about the parents' genotypes?
- Both parents are homozygous recessive for black fur.
- One parent is homozygous dominant and the other is homozygous recessive.
- Both parents are heterozygous for black fur. (correct)
- Both parents are homozygous dominant for black fur.
If a zygote is described as heterozygous for a particular trait, what does this imply about the alleles present?
If a zygote is described as heterozygous for a particular trait, what does this imply about the alleles present?
- The zygote contains only one allele for that trait.
- The zygote contains two identical recessive alleles for that trait.
- The zygote contains two identical dominant alleles for that trait.
- The zygote contains one dominant and one recessive allele for that trait. (correct)
In genetics, what is the primary difference between an allele and a gene?
In genetics, what is the primary difference between an allele and a gene?
- A gene is a specific version of an allele.
- An allele is a specific version of a gene. (correct)
- A gene is a physical trait, while an allele is a genetic code.
- There is no difference; the terms are interchangeable.
Suppose brown eye color (B) is dominant and blue eye color (b) is recessive. If a homozygous recessive mother and a homozygous dominant father have children, what is the probability that their child will have blue eyes?
Suppose brown eye color (B) is dominant and blue eye color (b) is recessive. If a homozygous recessive mother and a homozygous dominant father have children, what is the probability that their child will have blue eyes?
In constructing a Punnett square, what is the significance of using uppercase and lowercase letters to represent alleles?
In constructing a Punnett square, what is the significance of using uppercase and lowercase letters to represent alleles?
An individual's genotype provides the information for the possible observable traits, what is the term called?
An individual's genotype provides the information for the possible observable traits, what is the term called?
If a scientist is studying how specific traits are passed from parents to offspring in a group of dogs, which field of study are they primarily working in?
If a scientist is studying how specific traits are passed from parents to offspring in a group of dogs, which field of study are they primarily working in?
In selective breeding programs, what is the primary goal when choosing parent organisms?
In selective breeding programs, what is the primary goal when choosing parent organisms?
What is the significance of the arrangement of the four chemical bases (Guanine, Cytosine, Adenine, and Thymine) in DNA?
What is the significance of the arrangement of the four chemical bases (Guanine, Cytosine, Adenine, and Thymine) in DNA?
Imagine researchers discover a new molecule within cells that has a double-helix structure and is composed of repeating nucleotide units. Based on this information, what is the most likely function of this molecule?
Imagine researchers discover a new molecule within cells that has a double-helix structure and is composed of repeating nucleotide units. Based on this information, what is the most likely function of this molecule?
If a new organism is discovered and found to have a slightly different set of chemical building blocks in its DNA than the standard Guanine, Cytosine, Adenine, and Thymine (G, C, A, T), what would be the most reasonable hypothesis?
If a new organism is discovered and found to have a slightly different set of chemical building blocks in its DNA than the standard Guanine, Cytosine, Adenine, and Thymine (G, C, A, T), what would be the most reasonable hypothesis?
Considering the structure of DNA and its location within a cell, what is the primary reason DNA must be exquisitely thin?
Considering the structure of DNA and its location within a cell, what is the primary reason DNA must be exquisitely thin?
Which of the following statements accurately describes the relationship between genes, chromosomes, and the genome?
Which of the following statements accurately describes the relationship between genes, chromosomes, and the genome?
If a scientist is studying a specific locus on a chromosome, what biological entity is the scientist most likely examining?
If a scientist is studying a specific locus on a chromosome, what biological entity is the scientist most likely examining?
What determines the sex of a human offspring?
What determines the sex of a human offspring?
If a cell contains 46 chromosomes, how many pairs of chromosomes are present in the cell?
If a cell contains 46 chromosomes, how many pairs of chromosomes are present in the cell?
How would a scientist differentiate between a nucleotide and a base?
How would a scientist differentiate between a nucleotide and a base?
Which statement accurately describes the function of the X chromosome?
Which statement accurately describes the function of the X chromosome?
What is the primary role of DNA within a cell?
What is the primary role of DNA within a cell?
Given the length of DNA in a single human cell, what structural adaptation allows it to fit within the cell's nucleus?
Given the length of DNA in a single human cell, what structural adaptation allows it to fit within the cell's nucleus?
Which of the following statements accurately describes the relationship between genes, DNA, and chromosomes?
Which of the following statements accurately describes the relationship between genes, DNA, and chromosomes?
If a somatic cell in an organism contains 46 chromosomes, how many chromosomes would be present in each of the new cells produced after mitosis?
If a somatic cell in an organism contains 46 chromosomes, how many chromosomes would be present in each of the new cells produced after mitosis?
What is the primary purpose of meiosis?
What is the primary purpose of meiosis?
A plant breeder crosses two pea plants. One is purebred for round seeds (RR), and the other is purebred for wrinkled seeds (rr). What will be the genotype of the offspring in the first generation (F1)?
A plant breeder crosses two pea plants. One is purebred for round seeds (RR), and the other is purebred for wrinkled seeds (rr). What will be the genotype of the offspring in the first generation (F1)?
In a certain species of flower, red color (R) is dominant over white color (r). If a heterozygous red flower (Rr) is crossed with a white flower (rr), what is the probability of producing a white flower offspring?
In a certain species of flower, red color (R) is dominant over white color (r). If a heterozygous red flower (Rr) is crossed with a white flower (rr), what is the probability of producing a white flower offspring?
Mules are typically sterile because they have an odd number of chromosomes. Which aspect of meiosis is most directly disrupted by having an odd number of chromosomes.
Mules are typically sterile because they have an odd number of chromosomes. Which aspect of meiosis is most directly disrupted by having an odd number of chromosomes.
A scientist is studying a new species of plant. They observe that the plant's flower color can be either purple or white. After conducting several crosses, they determine that purple flower color is dominant. Which of the following crosses would allow the scientist to definitively determine the genotype of a plant with purple flowers?
A scientist is studying a new species of plant. They observe that the plant's flower color can be either purple or white. After conducting several crosses, they determine that purple flower color is dominant. Which of the following crosses would allow the scientist to definitively determine the genotype of a plant with purple flowers?
In the context of genetics, what is the significance of alleles?
In the context of genetics, what is the significance of alleles?
A certain species of bird has two alleles for feather color: black (B) and yellow (b). Black is dominant to yellow. If two heterozygous birds (Bb) mate, what is the probability that their offspring will also be heterozygous (Bb)?
A certain species of bird has two alleles for feather color: black (B) and yellow (b). Black is dominant to yellow. If two heterozygous birds (Bb) mate, what is the probability that their offspring will also be heterozygous (Bb)?
How does mitosis contribute to the growth and repair of multicellular organisms?
How does mitosis contribute to the growth and repair of multicellular organisms?
Flashcards
Heritable Traits
Heritable Traits
Traits or characteristics passed down from parents to offspring.
DNA
DNA
The inherited material responsible for variation; a double-helix structure found in the nucleus.
Breeding Programs
Breeding Programs
Using genetic information to breed plants and animals with desired characteristics.
DNA Structure Discovery
DNA Structure Discovery
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Four DNA Chemicals
Four DNA Chemicals
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Genetic Code
Genetic Code
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Chromosomes
Chromosomes
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Gene
Gene
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Genome
Genome
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Nucleotide
Nucleotide
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Base Pairs
Base Pairs
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X Chromosome
X Chromosome
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Y Chromosome
Y Chromosome
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Alleles
Alleles
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Recessive Trait
Recessive Trait
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Homozygous
Homozygous
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Heterozygous
Heterozygous
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Genotype
Genotype
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Punnett Square
Punnett Square
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Somatic Cells
Somatic Cells
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Mitosis
Mitosis
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Meiosis
Meiosis
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Gamete
Gamete
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Trait
Trait
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Purebred
Purebred
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Hybrid
Hybrid
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Dominant Trait
Dominant Trait
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Study Notes
- Science 9 covers "DNA and Genetics"
Genetics Overview
- Certain traits or characteristics are inherited or heritable from parents.
- Due to sexual reproduction, variation occurs in how genes are expressed.
DNA Basics
- DNA, as inherited material, causes variation in the double-helix configuration.
- Arrangement of DNA is located inside the nucleus of all the cells.
- The DNA is the transmitter of the genetic code.
- Offspring resemble parents because characteristics pass from generation to generation.
- Breeding programs use genetic information to produce plants and animals with specific characteristics.
Watson, Crick, and Franklin
- James Watson and Francis Crick explained in 1953 that DNA has chemical building blocks.
- These blocks carry instructions causing diversity.
- The work was accomplished based on X-ray photos by Rosalind Franklin.
DNA Molecule Construction
- DNA molecule construction is in the form of a twisted ladder.
- The sides of the ladder are identical.
- Its steps are components with four chemicals that are different: Guanine, Cytosine, Adenine, and Thymine.
- Composition and arrangement of these chemicals code what cells can read.
- Arrangement into instructions is the "genetic code", that makes a particular organism look the way it does and acts as a blueprint.
DNA Location & Structure
- DNA is in the nucleus of animal and plant cells.
- DNA fits into the nucleus because it is exquisitely thin.
- 20 billion strands the width of a human hair.
- DNA divides into segments: chromosomes and shorter units called genes.
- All genes add up to become the genome.
- Chromosomes are large DNA pieces containing many genes.
- Base pair refers to the terms nucleotide, with slightly different meanings.
- A nucleotide is the structure of Cytosine, Adenine, Guanine, or Thymine, attached with deoxyribose sugar attached to phosphate.
- A base is Cytosine, Adenine, Guanine, or Thymine.
- A always pairs to T, and G always pairs to C, as base pairs.
- DNA is the large molecule in cells' nuclei that stores/passes on offspring information.
- The name is deoxyribonucleic acid.
- Humans have 46 chromosomes and 25,000 genes in their genome.
- The human genome has over 3 billion base pairs.
- There is 1 meter of DNA packed into every cell.
- If formed into a single strand, total DNA would stretch 10 billions miles.
Chromosomes & Sex
- Because DNA is responsible for a cell's physical and chemical characteristics, lots of DNA is inside the cell.
- DNA is approximately 2 meters in length.
- Total length is 1,000,000 bigger than what cell fits into, therefore DNA arranges itself into packages, or chromosomes.
- Each cell nucleus has 46 chromosomes arranged in 23 pairs.
- X chromosomes: Present in both males and females, contains genes needed for body and vision functions.
- Y chromosomes: Only in males and contains gene development.
- Mothers always provide an X chromosome and fathers provide either Y or an X.
Genes & Alleles
- Genes are DNA segments contributing to phenotype or exterior look/function.
- Genes occupy a fixed position or a locus on a chromosome.
- Offspring inherit genes from both parents.
- Genes in color are represented with two possibilities.
- Possible forms are known as alleles.
- Alleles are different versions of same gene.
- Genotype has a genetic code that informs cells for a particular trait.
- Phenotype is a visible expressed trait.
Cell Division - Mitosis
- Mitosis produces two new cells with same the number of chromosomes.
- Mitosis are used for growth and repair, replacing dead cells.
- 50-70 billion cells die in one's body every day.
- Mitosis essentially produces more of the same cells.
Cell Division - Meiosis
- 2nd type of cell division.
- Meiosis produces 1/2 the DNA of a normal cell or gamete.
- The cell division is used for sexual reproduction.
- Produces cells with 1/2 the DNA that is 1/2 the chromosomes of a cell.
- Gametes are male and female.
- Mules are from horses and donkeys.
- Mules get mules 63 chromosomes.
- Mules are very sterile.
Traits, Purebreds and Hybrids
- Traits are genetically determined characteristics.
- A purebred is an organism with identical alleles/genes.
- A hybrid: organism produces offspring that are genetically dissimilar from parents.
- Dominant traits express preferentially over another.
- Alleles are what causes a kitten to have black coat.
- Recessive traits are preferentially masked but not expressed or visible.
- A zygote is a cell that results from the fusing of male and female gametes, has a set of chromosomes.
- Homozygous refers to having two of the same alleles, with the same version.
- Heterozygous refers to having two different alleles.
- An upper case letter is used for the dominant trait and a lower case letter is used for a recessive trait.
- Incomplete dominance: intermediate inheritance or combined phenotype.
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