Week 1 Notes

Physiology

The study of functions of organisms, focusing on how and why the body works.

Structural Levels of Organization

Hierarchical arrangement of biological structures from atoms/molecules to organisms.

External Environment

Components outside the body, such as air, nutrients, and water.

Internal Environment

Components inside the body, including cells and fluids, separated by epithelium.

Homeostasis

Maintenance of a relatively constant internal environment; a unifying theme in physiology.

Homeostatic Control Systems

Regulatory responses to maintain homeostasis, classified as intrinsic/local or extrinsic/systemic controls.

Regulated Variables

Conditions maintained by homeostatic control, such as temperature, pH, and nutrient concentration.

Set Point

The desired range for a regulated variable that the body aims to maintain.

Homeostatic Response

The body's reaction to an error signal to restore homeostasis, involving stimulus, sensor, integrating center, and effectors.

Feedback

Responses made after a change is detected, categorized into negative feedback (stabilizing) and positive feedback (directional).

Diabetes

A metabolic disease affecting blood glucose levels and urine volume, with types including Type I, Type II, gestational diabetes, and diabetes insipidus.

Chemical Bonding

Types of bonds including ionic (transfer of electrons), covalent (sharing of electrons), and hydrogen (attraction between molecules).

Biomolecules

Molecules synthesized by cells containing C-C covalent bonds, formed through dehydration synthesis and broken down by hydrolysis.

Carbohydrates

Biomolecules containing C, H, and O, serving functions like energy storage and structural support.

Lipids

Non-polar biomolecules including triglycerides, phospholipids, eicosanoids, and steroids, serving functions like energy storage and cellular communication.

Proteins

Biomolecules made of amino acids, providing structural support, enzymatic activity, and chemical signaling.

Levels of Protein Structure

Hierarchical organization of proteins from primary (amino acid sequence) to quaternary (multiple polypeptide chains).

Nucleic Acids

Biomolecules that store genetic information (DNA) and facilitate DNA expression (RNA).

DNA vs RNA

DNA is double-stranded with deoxyribose sugar, while RNA is single-stranded with ribose sugar, involved in protein synthesis.

DNA Replication

The process of copying DNA, occurring in the nucleus and involving enzymes like helicase and DNA polymerase.

Protein Synthesis

The central dogma of molecular biology, involving transcription (DNA to mRNA) and translation (mRNA to protein).

Genetic Code

The language of mRNA codons that correspond to amino acids and stop signals, with start codon AUG.

Translation

The process of converting mRNA into proteins, occurring in the cytoplasm with the help of ribosomes and tRNA.

stop codon and function

stop codon (UAA, UAG, UGA) in mRNA signals the end of protein synthesis, instructing the ribosome to stop translation and release the completed polypeptide chain

Transcription

Fill in the blank: The process of copying genetic information from DNA to mRNA is called __________.

Where in the cell does transcription take place?

Transcription occurs in the nucleus of eukaryotic cells. In prokaryotic cells, it takes place in the cytoplasm.

1. Triglycerides - energy storage fats, insulation, and protection.

2. Phospholipids - major components of cell membranes.

3. Steroids - hormones and signaling molecules (e.g., cholesterol).

4. Eicosanoids - chemical messenger for cellular communication

Main types of lipids

Saturated fats have no double bonds between carbon atoms so they are tightly packed, and are typically solid at room temperature (e.g., butter, lard).

Unsaturated fats are loosely packed and contain one or more double bonds causing kinks and are usually liquid at room temperature (e.g., olive oil, fish oil).

Saturated vs unsaturated fats?

Carbohydrates and its primary function in the body

Carbohydrates are organic compounds made of carbon, hydrogen, and oxygen. Their primary function is to provide energy to the body, serving as a key source of fuel for cells, particularly during physical activity and brain function.

What is an example of a negative feedback loop in the human body?

The regulation of body temperature. When body temperature rises, mechanisms like sweating are activated to cool the body down, while if it drops, shivering generates heat to restore normal temperature.

What is an example of a positive feedback loop in the body?

Childbirth is a key example. During labor, the release of oxytocin increases contractions, which push the baby toward the cervix. This pressure stimulates more oxytocin release, intensifying contractions until delivery occurs.

The total body water is divided into two main compartments: ________, which includes the fluid found within cells, and ________, which consists of the fluid outside cells, including interstitial fluid and plasma.

Intracellular fluid (ICF), Extracellular fluid (ECF)

What is the difference between intrinsic and extrinsic controls in the body?

Intrinsic controls are mechanisms that originate from within an organ or tissue, regulating its function independently (e.g., the heart's pacemaker cells).

Extrinsic controls involve external factors, such as hormones or nervous system signals, that influence organ function from outside (e.g., adrenaline affecting heart rate).