Podcast
Questions and Answers
What is the genotype of an individual that is affected by a recessive trait?
What is the genotype of an individual that is affected by a recessive trait?
Which genotype represents an unaffected carrier for a recessive trait?
Which genotype represents an unaffected carrier for a recessive trait?
In a pedigree analysis, which statement is true regarding dominant traits?
In a pedigree analysis, which statement is true regarding dominant traits?
Identify the correct components of a nucleotide.
Identify the correct components of a nucleotide.
Signup and view all the answers
If a strawberry cell has a base chromosome number of 7, how many chromosomes would it have?
If a strawberry cell has a base chromosome number of 7, how many chromosomes would it have?
Signup and view all the answers
What is the chromosome number in a gamete of an organism with 46 chromosomes?
What is the chromosome number in a gamete of an organism with 46 chromosomes?
Signup and view all the answers
Why are mules typically infertile?
Why are mules typically infertile?
Signup and view all the answers
What is a characteristic of a homozygous organism?
What is a characteristic of a homozygous organism?
Signup and view all the answers
In which circumstance will a sex-linked trait appear in females?
In which circumstance will a sex-linked trait appear in females?
Signup and view all the answers
What occurs during nondisjunction in meiosis?
What occurs during nondisjunction in meiosis?
Signup and view all the answers
If a zygote has an XXY chromosome arrangement, where may the nondisjunction have occurred?
If a zygote has an XXY chromosome arrangement, where may the nondisjunction have occurred?
Signup and view all the answers
How many sets of chromosomes do strawberries have?
How many sets of chromosomes do strawberries have?
Signup and view all the answers
Which parents can produce a child with freckles if both are homozygous recessive?
Which parents can produce a child with freckles if both are homozygous recessive?
Signup and view all the answers
Study Notes
Chromosome Numbers and Reproduction
- Gametes have half the chromosomes of somatic cells (haploid). For example, if an organism has 46 total chromosomes, each gamete will have 23.
- Donkeys have 62 chromosomes (31 pairs). A donkey zygote has 62 chromosomes formed by the fusion of gametes, each with 31 chromosomes.
- Mules are infertile due to a hybrid combination of horse (64 chromosomes) and donkey (62 chromosomes). This results in 63 chromosomes, leading to pairing issues during meiosis, causing infertility.
Genetics Terms
- Homozygous: An organism with two identical alleles for a trait (e.g., AA or aa).
- Heterozygous: An organism with two different alleles for a trait (e.g., Aa).
- Genotypes: Homozygous genotypes include AA or aa, while heterozygous genotypes are represented as Aa.
- Recessive traits require both alleles to be recessive (aa) for expression, whereas dominant traits only require one dominant allele to be expressed.
Traits, Mutations, and Sex-Linked Traits
- Co-dominant traits: Both alleles are fully expressed in the phenotype. In blood types, IAIB genotype results in both A and B antigens.
- Sex-linked traits (X-linked): Females need two copies of the allele for expression (XX). Males (XY) only need one copy.
- Klinefelter syndrome (XXY): Males with extra X chromosomes (XXY) can exhibit traits usually seen in females.
- Nondisjunction: Failure of chromosomes to separate during Anaphase I or II of meiosis. Can occur in either parent (egg or sperm).
Strawberry Chromosomes
- Strawberries are octoploid (8 sets of chromosomes). If the base number is 7, a strawberry cell has 56 chromosomes (8 x 7).
Pedigree Analysis
- Recessive traits: Appear when both parents are carriers and pass down recessive traits (e.g., aa phenotype) to their offspring.
- Dominant traits: Appear in every generation.
- Genotype Deduction: Determine genotypes by analyzing inheritance patterns. Symbols like A/a can be used to deduce individual genotypes based on phenotypes.
DNA Structure
- DNA structure includes phosphate groups, deoxyribose sugars, and nitrogenous bases (A, T, G, C).
- A nucleotide consists of one phosphate, one sugar, and one nitrogenous base.
- DNA strands are antiparallel (one strand 5' to 3', the other 3' to 5') with complementary base pairing (A-T, G-C).
Pedigree Genotype Deduction
- Analyzing inheritance patterns to determine possible genotypes.
- Use symbols to deduce genotypes based on an individual's phenotype and family history. For instance, unaffected individuals might be homozygous dominant (AA) or heterozygous (Aa) for a recessive trait.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
This quiz covers fundamental concepts in genetics, including chromosome numbers in different species, the nature of gametes, and key genetic terms like homozygous and heterozygous. Dive into the world of inheritance, mutations, and reproductive biology.
