Genetics Overview Quiz

Genetics

• Genotype refers to the genetic makeup of an organism, while phenotype refers to the observable traits.
• Recessive traits are only expressed when two copies of the recessive allele are present.
• Dominant traits are expressed even when only one copy of the dominant allele is present.
• Chromosomes are long strands of DNA wound around histones, containing many genes.
• Genes are segments of DNA that contain the instructions for making proteins.
• Telomeres are regions at the end of chromosomes that protect the DNA during cell division.
• Alleles are alternative forms of a gene found at the same location on a chromosome.
• Gene loci are specific locations on a chromosome where a particular gene is located.

Other Forms of DNA Differences

• Tandem repeats are sequences of two or more DNA bases that are repeated many times in a chromosome. They are often found in non-coding DNA and can be used in DNA fingerprinting.
• Translocations occur when a chromosome breaks and the fragments reattach to different chromosomes. They can be balanced (equal exchange) or unbalanced (unequal exchange), leading to genetic diseases.
• Duplication involves the production of one or more copies of a DNA segment, which can lead to genetic diseases like Charcot-Marie-Tooth.
• Insertions and deletions refer to the addition or loss of nucleotides or sections of chromosomes, respectively. Deletion is associated with genetic disorders like cystic fibrosis and cat cry syndrome.

Epigenetics

• Epigenetics studies heritable changes in gene expression that do not involve alterations in the DNA sequence.
• Environmental factors like stress, diet, smoking, and radiation can influence epigenetic changes.
• Twin studies can be used to investigate the influence of genetics vs. environment on phenotypic variations.

The Immune System

• Phagocytes are cells that engulf and destroy foreign pathogens.
• Granulocytes are a type of phagocyte that die after engulfing a threat, contributing to pus formation.
• Macrophages are large, long-lived phagocytes that present fragments of ingested pathogens on their surface.
• Dendritic cells are phagocytes with a large surface area, also presenting antigens on their surface.

Inflammation

• Inflammation is a response to harmful stimuli, involving the activation of the innate immune system.
• Leukocytes release chemicals that cause redness, swelling, heat, itching, and pain.
• Mast cells release histamine and cytokines, contributing to inflammation.
• The complement system is activated, and blood clotting begins.
• Neutrophils and macrophages are attracted to the site of inflammation.
• Cytokines are released, causing fever and other systemic symptoms.

The Adaptive Immune Response

• MHC (Major Histocompatibility Complex) plays a crucial role in distinguishing self from non-self.
• MHC molecules are found on the surface of all cells and display both self and non-self components.
• Antigen-presenting cells (macrophages and dendritic cells) present MHC-bound antigens to initiate the adaptive immune response.

Antigens

• Antigens are substances that can stimulate the adaptive immune response by triggering antibody production.
• B-cells recognize antigens directly.
• T-cells recognize antigens presented on MHC molecules.

B Lymphocytes (B-cells)

• B-cells originate and mature in the bone marrow.
• Each B-cell recognizes one specific antigen.
• B-cells produce and release antibodies.

Homeostasis

• Homeostasis is the ability of an organism to maintain internal stability despite external changes.
• It involves regulating body temperature, blood glucose, oxygen levels, blood pressure, and lipid levels.
• Homeostasis is essential for the proper function of various bodily processes and relies on feedback systems.

Eating

• Eating is a complex behavior that serves various purposes, including maintaining homeostasis, pleasure, social interaction, and energy provision.
• Different dietary components, such as carbohydrates, proteins, and fats, provide different types of energy and building blocks for the body.

Gastrointestinal (GI) Digestion

• Digestion begins in the mouth, where food is ground and saliva breaks down carbohydrates.
• The esophagus transports food to the stomach.
• The stomach breaks down food and kills bacteria with its acidic environment. Proteins are digested into amino acids in the stomach.
• Fats are broken down by bile, produced by the liver and stored in the gallbladder, and released into the duodenum.

Test your understanding of key genetics concepts including genotypes, phenotypes, and the role of alleles and chromosomes. This quiz covers essential terminology and concepts that form the foundation of genetic science. Prepare to explore the intricacies of DNA and its functions.