Anatomy and Physiology

Anatomy – the study of the structure and form of the body
Physiology – the study of the functioning of the body
Form and function are connected; structure determines function and vice versa
Note: anatomical directional terms are used to describe the locations of structures

Atom → Molecule → Cell → Tissue → Organ → Organ System → Organism
Note: each level is a group of the prior level (e.g., a tissue is a group of cells)

The Cytoplasm
- The internal, liquid component of a cell
- Contains subunits called organelles that perform various cellular functions
DNA, Chromatin, and Chromosomes
- DNA – molecule containing the genetic information of the organism; shape is a double helix (like a twisted ladder)
- Chromatin – a partially-condensed form of DNA (as seen within the nucleus) formed by wrapping the double helix around proteins
- Chromosomes – the most condensed form of DNA, formed by the coiling of chromatin; only seen at times of cell division
The Nucleus
- Holds the cell’s DNA in the form of chromatin
- Controls and regulates the cell’s activities
Mitochondria
- “Powerhouse” of the cell
- Generates cellular energy in the form of an ATP molecule
- ATP production is called cellular respiration
Ribosomes
- Small structures that build proteins
- Proteins are structural and functional molecules that are built of amino acids; examples include enzymes, hormones, fibers, etc.
Cytoskeleton
- Series of rod-shaped proteins
- Provides support for cell shape, and a framework needed for generating cell movements
Cell Membrane
- Separates internal and external cellular environments
- Transports materials into and out of cells

Cell Cycle – the series of events including the growth of a cell and its division into two “daughter cells”
Interphase – includes the growth of a daughter cell and the replicating of the DNA
G1 – Cell growth
S – DNA replication
G2 – Growth and prep for cell division
M – Mitosis

A cell cycle is a series of events that takes place in a cell as it grows and divides
A cell spends most of its time in Interphase, where it grows, replicates chromosomes, and prepares for cell division
The cell then leaves Interphase, undergoes Mitosis, and completes its division
The resulting cells (daughter cells) each enter their own Interphase and begin a new round of the cell cycle

Mitosis – the division of a cell into two daughter cells
Functions of Mitosis:
- Growth – adding cells to an organism as it grows and develops
- Repair – replaces old and damaged cells

PMAT stands for Prophase, Metaphase, Anaphase, Telophase
Prophase (first stage): chromosomes condense and become visible as sister chromatids; spindle fibers begin to form; nucleolus breaks down; centrioles move toward opposite poles; the nuclear envelope breaks down toward the end
Metaphase: duplicated chromosomes line up along the center (metaphase plate) of the cell
Anaphase: duplicated chromosomes split at the centromere and are pulled to opposite poles; sister chromatids separate
Telophase: two new nuclei form; the cytoplasm divides as the cell membrane pinches to form two daughter cells
Interphase (before Mitosis): DNA material is copied and the chromosomes are replicated; DNA replication occurs during S phase; centrosomes/centrioles duplicate
In Prophase, DNA condenses into chromosomes; nucleus breaks down; spindle fibers form; centrioles move apart; nuclear envelope breaks down

Two pairs of centrioles are present
Nucleus with chromatin, nucleolus, nuclear envelope, and plasma membrane are components involved in organizing and enclosing genetic material
Chromosome (two sister chromatids joined at centromere) and sister chromatids are key structures during replication and separation
Stages of Mitosis labeled: Interphase (Synthesis of cellular components for division, including DNA replication and centriole duplication during interphase) and Prophase (coiling of chromatin into chromosomes; nucleolus breaks down; spindle fibers form; centrioles migrate; nuclear envelope breaks down)

Metaphase – duplicated chromosomes align at the center of the cell
Anaphase – duplicated chromosomes split into single chromosomes and move to opposite poles
Telophase – two new nuclei form; cytoplasm divides, resulting in two daughter cells

Purpose of transcription: to make RNA copies of genes
Purpose of translation: to synthesize proteins for cellular functions
Translation produces proteins; transcription produces RNA types: mRNA, tRNA, rRNA, and non-coding RNA
In prokaryotes, translation and transcription occur in the cytoplasm; in eukaryotes, translation happens on ribosomes and transcription occurs in the nucleus

Transcription: segments of DNA called genes are copied into RNA
Translation: the RNA molecule is used by a ribosome to carry out the building of a protein
Therefore, DNA directs which proteins are built and when

Understanding the cell cycle is essential for studying growth, development, and cancer biology
Proper function of the nucleus, mitochondria, and ribosomes is critical for cellular health and energy management
The central dogma (DNA → RNA → Protein) underpins genetics, biotechnology, and medicine
Knowledge of transcription and translation informs gene expression studies and therapeutic strategies
Ethical and practical implications arise when manipulating genetic material and targeting cell cycle processes in medical treatments