Types of Reproduction, Genetics, and Cellular Transport

Flashcards covering reproduction types, meiosis, Mendelian and population genetics, cell division, and cellular transport based on lecture notes.

What is asexual reproduction and what are its key features?

Asexual reproduction involves only one parent, producing genetically identical offspring (clones). Key features: relies on mitosis or simple fission, does not use gametes or fertilization, is fast and consumes fewer resources, and low genetic diversity can limit adaptation to environmental changes.

What are three mechanisms of asexual reproduction and their given examples?

Binary Fission (example: Paramecium), Budding (example: Hydra), and Fragmentation and Regeneration.

What is sexual reproduction and what are its key features?

Sexual reproduction involves two parents combining genetic material via meiosis and fertilization to create unique offspring. Key features: takes more time and energy than asexual reproduction, generates high genetic variation to help populations adapt, and supports natural selection by potentially masking or removing harmful traits.

What features are shared by both asexual and sexual reproduction?

Both types copy DNA before cell division, both involve nuclear division in eukaryotic cells, and both ensure the survival of the species.

What is the difference between diploid ($2n$) and haploid ($n$) cells in humans?

Diploid ($2n$) cells contain two sets of chromosomes (e.g., human body cells with $46$ chromosomes), whereas haploid ($n$) cells contain one set of chromosomes (e.g., human gametes with $23$ chromosomes).

What occurs during Meiosis I and Meiosis II?

In Meiosis I, homologous chromosomes pair as tetrads and separate. In Meiosis II, sister chromatids separate into individual gametes.

What are the four sources of genetic variation during meiosis and sexual reproduction?

Crossing-Over (non-sister chromatids exchange DNA segments during Prophase I), Independent Assortment (chromosomes align randomly and separate during Metaphase I), Random Fertilization (any sperm can fertilize any egg), and Mutations (errors during DNA replication).

How do mitosis and meiosis compare regarding offspring cell count, genetic identity, and function?

Mitosis produces two identical diploid cells used for growth, repair, and asexual reproduction. Meiosis produces four non-identical haploid cells strictly for making gametes in sexual reproduction.

How does cytokinesis differ between animal cells and plant cells?

In animal cells, a cleavage furrow pinches apart the cells. In plant cells, a cell plate forms to divide the cells.

What are Mendel's Law of Segregation and Law of Independent Assortment?

Law of Segregation: Alleles separate during meiosis, so each gamete carries only one allele per gene. Law of Independent Assortment: Genes on different chromosomes segregate independently during gamete formation.

What phenotypic outcomes result from the monohybrid crosses $BB \times bb$ and $Bb \times Bb$?

For $BB \times bb$, $100\%$ are $Bb$ (heterozygous) showing the dominant phenotype. For $Bb \times Bb$, there is a $3:1$ phenotypic ratio ($75\%$ dominant, $25\%$ recessive).

What phenotypic ratio and key genotype frequencies result from a dihybrid cross ($AaBb \times AaBb$)?

The phenotypic ratio is $9:3:3:1$. Key genotype frequencies listed are $116$ AABb, $116$ aabb, and $144$ AaBb.

What are the Hardy-Weinberg equations for allele frequencies and genotype frequencies?

Allele Frequencies: $p + q = 1$ (where $p =$ dominant allele, $q =$ recessive allele). Genotype Frequencies: $p^2 + 2pq + q^2 = 1$.

In a group of $1000$ plants where $180$ are short ($tt$), what are the calculated Hardy-Weinberg values?

$q^2 = 0.18$, $q \approx 0.424$, $p \approx 0.576$, and the heterozygous proportion is $\approx 50\%$.

What is passive transport and how do simple diffusion, facilitated diffusion, and osmosis work?

Passive transport moves molecules from high to low concentration without energy (ATP). Simple diffusion moves solutes directly through the membrane, facilitated diffusion moves molecules via proteins without energy, and osmosis moves water from high to low water concentration.

How do isotonic, hypotonic, and hypertonic solutions affect a cell?

Isotonic: Equal solute concentration (no net water movement). Hypotonic: Lower solute concentration outside, causing the cell to swell. Hypertonic: Higher solute concentration outside, causing the cell to shrink.

What is active transport and what are two types of bulk transport?

Active transport moves molecules from low to high concentration, requiring energy (ATP). Bulk transport types include Endocytosis (cell engulfs large molecules into a vesicle) and Exocytosis (vesicles fuse with the membrane to release materials outside the cell).