Untitled Flashcards Set

Detailed Genetic Flashcards

Heredity

Traits: Traits are characteristics inherited from parents, encompassing physical attributes (such as height, eye color), behavioral tendencies (like aggression or sociability), and biochemical properties (such as blood type).

Alleles: Alleles are different versions of a gene that exist at a specific locus (position) on a chromosome. Each individual inherits two alleles for each gene, one from each parent, which can be dominant or recessive.

Chromosomes: Chromosomes are structures within cells that contain DNA. In humans, there are 23 pairs of chromosomes, totaling 46. Each chromosome houses many genes, and the arrangement and number are critical for proper cellular functioning and inheritance.

Homozygous vs. Heterozygous: Individuals can be homozygous, meaning they have two identical alleles for a particular trait (e.g., AA or aa), or heterozygous, with two different alleles (e.g., Aa). This distinction is important for understanding genetic variation and inheritance patterns.

Phenotype and Ratios: The phenotype refers to the observable traits of an organism, which are the result of its genotype and environmental influences. Ratios of phenotypes can be predicted using Punnett squares, which illustrate potential outcomes of genetic crosses between parents.

Genotype and Ratios: The genotype of an individual encompasses its genetic constitution, which influences its traits. Different genotypes can yield varying phenotypes, and understanding this relationship helps in predicting inheritance patterns. Ratios of offspring genotypes can also be calculated using tools like Punnett squares.

XX and XY: The sex chromosomes, represented as XX for females and XY for males, determine an individual's sex. The presence of the Y chromosome is responsible for male characteristics, while the absence leads to female characteristics.

Mendel and Peas

Gregor Mendel: Known as the father of modern genetics, Mendel conducted experiments with pea plants in the mid-19th century. Through his observations, he established key principles of inheritance.

Law of Segregation: This law states that during gamete formation, the alleles for a trait separate, so each gamete carries only one allele for each gene.

Law of Independent Assortment: It asserts that genes for different traits assort independently during gamete formation, which leads to genetic variation in offspring.

Cells and Organelles Jobs

Organelle Functions: Each organelle within a cell performs specific functions vital for the cell’s survival and operation:

• Mitochondria: Known as the powerhouse of the cell, mitochondria produce ATP (adenosine triphosphate), the energy currency of the cell, through cellular respiration.

• Ribosomes: These are the sites of protein synthesis, where mRNA is translated into polypeptide chains that will fold into functioning proteins.

• Endoplasmic Reticulum (ER): This organelle is involved in the synthesis and transport of proteins (rough ER) and lipids (smooth ER), playing a key role in the modification and transport of biomolecules.

• Golgi Apparatus: It modifies, sorts, and packages proteins and lipids for secretion or delivery to other organelles, acting as a shipping center within the cell.

Mitosis and Meiosis

Mitosis: A process of cell division leading to two identical daughter cells, crucial for growth, development, and tissue repair. It includes phases: prophase, metaphase, anaphase, and telophase.

Meiosis: A specialized form of cell division that produces gametes (sperm and eggs). It includes two rounds of division — meiosis I and meiosis II — resulting in four genetically diverse haploid cells; this process introduces genetic variation through processes such as crossing over.

Cell Cycle

Phases: The cell cycle is divided into several key phases:

• Interphase: The cell undergoes growth and DNA replication, preparing for division.

• Mitosis: The nucleus divides, separating the duplicated chromosomes into two new nuclei.

• Cytokinesis: This phase includes the division of the cytoplasm, resulting in two distinct daughter cells.

Dichotomous Key

Taxonomy Tool: A dichotomous key is used in taxonomy to identify organisms based on a series of choices leading to the correct name of a species, using paired statements or questions that reflect observable characteristics.

Taxonomy

Classification Science: Taxonomy is the science of classifying organisms into hierarchical levels: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species. This system helps organize biological diversity and understand evolutionary relationships.

DNA

Genetic Material: DNA stands for Deoxyribonucleic Acid, and it is the molecule that carries genetic information in living organisms.

Double Helix Structure: The structure of DNA is a double helix, composed of two intertwined strands made up of nucleotides.

Nucleotides: These building blocks of DNA consist of a sugar (deoxyribose), a phosphate group, and a nitrogenous base (adenine, thymine, cytosine, or guanine) which encode genetic information.

Diffusion and Osmosis

Movement of Molecules:

• Diffusion: The process where molecules move from an area of higher concentration to an area of lower concentration, seeking equilibrium.

• Osmosis: A specific type of diffusion involving the movement of water across a semi-permeable membrane, which is crucial for maintaining cell turgor and homeostasis.

Hierarchy of Life

Organization Levels: The hierarchy of life consists of levels ranging from atoms to biospheres, which are organized as follows:

• Atoms → Molecules → Cells → Tissues → Organs → Organ Systems → Organisms → Populations → Communities → Ecosystems → Biosphere.

Pedigrees

Genetic Diagrams: Pedigrees are diagrams that display the occurrence and inheritance patterns of a genetic trait across several generations of a family, serving as a valuable tool in genetics to track hereditary conditions and relationships between family members.

Characteristics of Life

Defining Criteria: Living organisms are characterized by their ability to:

• Maintain cellular organization,

• Carry out metabolism,

• Achieve homeostasis,

• Grow and reproduce,

• Respond to stimuli,

• Adapt through evolution.

Genes

Units of Heredity: Genes are segments of DNA that serve as units of heredity, encoding information necessary for the production of proteins, which ultimately determine specific traits.

Centromere: The centromere is a crucial part of a chromosome that links sister chromatids together, playing a vital role during cell division where it ensures the proper separation of chromatids.

Proteins and DNA

Synthesis: Proteins are synthesized according to the instructions encoded in DNA, which dictates the amino acid sequence through a genetic code.

Codons: A codon is a sequence of three nucleotides that specifies a particular amino acid, and it is crucial for translating the genetic information during protein synthesis.

Amino Acids: These are the building blocks of proteins, and they are linked together in a specific sequence during synthesis to form functional protein structures.

Punnett Squares

Predictive Tool: Punnett squares are grid systems that help predict the possible genotypes and phenotypes of offspring from a genetic cross between two parents, illustrating the likelihood of inheriting specific traits.

Parts of a Cell

Major Components: Key structures found within cells include:

• Cell Membrane: Defines the boundary of the cell and regulates the movement of substances in and out.

• Nucleus: Contains genetic material (DNA) and controls cellular activities.

• Cytoplasm: The jelly-like fluid where organelles are suspended, providing a medium for metabolic reactions.

• Organelles: Specific structures (like mitochondria, ribosomes, etc.) that perform dedicated functions critical for cell survival.

Cell Theory

Key Principles: The cell theory outlines fundamental concepts about cells:

• All living organisms are composed of cells.

• The cell is the basic unit of life.

• All cells arise from pre-existing cells, emphasizing the continuity of life through cellular division.

Cells contain the hereditary information necessary for regulating cell functions and for transmitting information to the next generation of cells.