Understanding Transplants, Immunity, and Disease Prevention
Transplants and Donations
Transplants: Diseased or injured organs, tissues, or cells are replaced with healthy ones from a donor.
The donor can be another person, the same person, or an animal.
Donations:
- Cells: Reproductive cells or stem cells from embryos and umbilical cord blood.
- Tissue: Blood transfusion.
- Organs: Heart, liver, kidneys.
Transplant Complications
Rejection: Immune system response from the host.
Infection: Organ health is analyzed.
Immune Response
Non-Specific Immune Response
If pathogens cross
Read MoreGene Expression: Transcription, Regulation, and RNA Maturation
Transcription Regulation
The activation or inhibition of transcription varies depending on the cell’s needs for different gene products. Transcription of each gene is carefully regulated to produce gene products in the necessary proportions. Any stage of transcription can be regulated, but the binding of polymerase and initiation stages are preferentially regulated. Proteins bound near and far from promoter sequences can affect gene expression levels. Protein binding can both activate and repress
Read MoreProkaryotes vs. Eukaryotes: Cell Structure, Function & Differences
Eukaryotes vs. Prokaryotes
- Organelles:
- Unique to Prokaryotes:
- Nucleoid: Region containing genetic material (DNA), lacks a membrane. Allows for rapid gene expression.
- Cell Wall: Provides structural support, protects against osmotic pressure changes, and helps maintain cell shape. Composition varies among bacteria (peptidoglycan in most).
- Plasmid: Small, circular DNA molecule separate from the chromosomal DNA. Often carries accessory genes, like antibiotic resistance. Facilitates horizontal gene transfer.
- Unique to Prokaryotes:
Energy Flow and Nutrient Cycles in Ecosystems
Energy Flow in Ecosystems
The sun is the principal source of energy input to biological systems. Energy flow is not a cycle. It starts from the sun and then that energy is harnessed by plants, which are eaten by animals, which are eaten by other animals. At each step, energy is lost to the environment (for example, by heat loss).
Food Chains and Food Webs
Food chain: A chart showing the flow of energy (food) from one organism to the next, beginning with a producer.
Food web: A network of interconnected
Read MoreCommon Diseases: Causes and Prevention
Diseases: The appearance of diseases in the systems and organs involved in nutrition is highly variable. They are caused by:
- Inadequate food consumption.
- Consumption of harmful substances such as tobacco, alcohol, and drugs.
- Lack of moderate physical exercise.
- Emotional stress.
Medicine helps to prolong human life.
Cardiovascular Diseases
Atherosclerosis: Results from the accumulation of cholesterol in blood vessel walls, leading to atheroma. When blood vessels narrow and blood circulation is impaired,
Read MoreBiology Review: Key Concepts and Answers
- Vaccines are used to introduce weakened or dead pathogens to stimulate the: immune system to react and be ready to fight future invasions by these microbes
- Which structure is closed or blocked to prevent sperm from traveling from the testes to the urethra in a vasectomy? A
- Sweat and skin secretion kill or limit the growth of many types of microbes. This control of microbes is an example of: a non-specific immune response against infection
- The fluid-filled structures in which the embryo is protected