Lecture 2 Flashcards
(17 cards)
What is a karyotype?
A karyotype is the arrangement of chromosomes, showing their number and types.
- Diploid (2n): Two copies of each chromosome (e.g., humans).
- Haploid (n): One copy (e.g., gametes).
Visual Mnemonic: A grid showing paired socks labeled ‘Diploid’ and single socks labeled ‘Haploid.’
What are examples of ploidy levels in organisms?
- Diploid (2n): Humans.
- Polyploid (4n/6n): Some plants like wheat (hexaploid).
Visual Mnemonic: A tomato with ‘4x’ written on it and a wheat stalk labeled ‘6x’ alongside human chromosomes ‘2x.’
What are the two types of cell division?
- Mitosis: Produces identical somatic cells.
- Meiosis: Produces gametes with genetic variation.
Visual Mnemonic: A copy machine for mitosis and a slot machine for meiosis (indicating randomness).
Who is Gregor Mendel and what did he discover?
Mendel discovered the principles of inheritance using pea plants, publishing his work in 1866.
Visual Mnemonic: A garden with peas labeled ‘Round’ and ‘Wrinkled,’ with Mendel holding a notebook.
What is a phenotype, and what is a genotype?
- Phenotype: Observable characteristics (e.g., blue eyes).
- Genotype: Genetic makeup (e.g., BB, Bb).
Visual Mnemonic: A flower labeled ‘Phenotype = color’ with hidden roots labeled ‘Genotype = genes.’
What is a Punnett square, and how is it used?
A Punnett square predicts offspring genotypes from parental alleles.
Example: Crossing Rr x Rr for peas.
Visual Mnemonic: A grid with parent traits along the edges and offspring combinations inside.
What are co-dominant alleles?
Co-dominant alleles both contribute to the phenotype (e.g., ABO blood groups).
Visual Mnemonic: A red and white flower producing a pink flower labeled ‘Co-dominance.’
What is sex-linked inheritance?
Inheritance of genes located on sex chromosomes (e.g., hemophilia on the X chromosome).
Visual Mnemonic: A family tree showing males affected by hemophilia.
What is X-chromosome inactivation?
In females, one X chromosome is randomly inactivated.
Example: Tortoiseshell cats.
Visual Mnemonic: A calico cat with patches labeled ‘Black X-active’ and ‘Orange X-active.’
What is a polygenic phenotype?
Traits controlled by multiple genes, such as height or skin color.
Visual Mnemonic: A graph of human heights forming a bell curve.
What are linked genes, and how do they recombine?
Linked genes are on the same chromosome and recombine during meiosis, increasing variation.
Visual Mnemonic: Two trains labeled ‘Genes’ on the same track splitting at a junction (recombination).
What is Down syndrome, and how does it occur?
Down syndrome is caused by trisomy 21, an extra copy of chromosome 21.
Visual Mnemonic: A chromosome labeled ‘21’ with three copies instead of two.
What is Klinefelter syndrome?
Klinefelter syndrome occurs in males with an extra X chromosome (XXY).
Visual Mnemonic: A male symbol (♂) with an extra ‘X’ next to it.
What is Patau syndrome?
Patau syndrome is caused by trisomy 13 (an extra chromosome 13).
Visual Mnemonic: A ‘13’ balloon with three strings.
What are the genotypes and phenotypes of ABO blood groups?
- Genotypes: AA, AO (A), BB, BO (B), AB (AB), OO (O).
- Phenotypes: A, B, AB, O.
Visual Mnemonic: Four labeled blood bags: A, B, AB, O, connected to a DNA strand.
What generates genetic variation in populations?
- Mutations: Changes in DNA.
- Recombination: Mixing during meiosis.
- Independent Assortment: Random distribution of chromosomes.
Visual Mnemonic: A kaleidoscope labeled ‘Genetic Variation.’
What is the difference between autosomal and sex-linked inheritance?
- Autosomal Inheritance: On non-sex chromosomes.
- Sex-Linked Inheritance: On X or Y chromosomes.
Visual Mnemonic: A tree splitting into two: one branch labeled ‘Autosomal’ and the other ‘Sex-Linked.’
