BIO65 || CH2: Cytology - The Study of Cells

Apical surface

The surface of a cell that opens up to the world, typically superficial and at the top.

Basal surface

The deep surface of a cell, located at the very bottom.

Lateral Surface

The sides of the cell surface.

Plasma Membrane

A protective barrier that separates the cell from the external environment, consists of phospholipid bilayer, cholesterol, glycolipids, proteins

Cytoplasm

The contents of the cell, including the cytosol, organelles, and the cytoskeleton.

Nucleus

An organelle that contains nucleoplasm (chromatin/DNA) and serves as the control center of the cell.

Phospholipids

Lipids that make up 75% of the plasma membrane, with hydrophilic heads and hydrophobic tails arranged in a lipid bilayer.

Cholesterol

Constitutes 20% of the plasma membrane, increasing its fluidity.

Glycolipids

Make up 5% of the plasma membrane, consisting of glucose (sugar) and phospholipids for cell signaling and recognition.

Integral (transmembrane) proteins

Proteins that pass through the membrane.

Glycoproteins

Proteins that adhere to either face of the membrane.

Peripheral proteins

Proteins that do not penetrate the entire plasma membrane.

Villi & Microvilli

Plasma membrane extensions that increase surface area, known as brush border.

Cilia

Motile cellular structures that help move substances along another structure.

Flagella

Cellular structures that propel sperm cells.

Tight Junctions

Cellular junctions that act as a sealant to prevent cells from detaching.

Desmosomes

Cellular junctions that help resist stress, similar to tight junctions, often found in muscle cells.

Gap Junction

Cellular junctions that allow communication between cells and enable them to send signals for a common function.

Cytoskeleton

Structural components of the cell that maintain its shape and organization, composed of microfilaments, intermediate filaments, and microtubules.

Microfilaments

Thin filaments made mostly of actin, supporting the plasma membrane and contributing to cell movement.

Intermediate filaments

Thicker filaments that provide strength to cells and tissues.

Microtubules

Largest filaments that hold organelles in place, guide organelles to their destinations within the cell, and are involved in cell division.

Organelles

Specialized structures within the cell that perform various functions, such as the nucleus, endoplasmic reticulum, ribosomes, Golgi complex, proteasomes, lysosomes, mitochondria, and centrioles.

Endoplasmic Reticulum

An organelle with rough and smooth types involved in protein synthesis, lipid metabolism, and detoxification.

Lysosomes

cell organelle filled with enzymes needed to break down certain materials in the cell (taking out the trash)

Ribosomes

Made in the nucleolus a portion of the nucleus in the cell
Assembles amino acids into proteins for use within or outside the cell; found in Rough ER & Cytoplasm

Golgi complex (aparratus)

Composed of cisterns
Vesicles (carrying something to be transported) are transported from the RER to Golgi complex
Golgi vesicles - packaged protein
→ Insertion into plasma membrane
→ Lysosomes
→ Secretory vesicles (releases components out of the cell)

Autophagy

A process in which lysosomes decompose damaged organelles to reuse their organic monomers

Apoptosis

programmed cell death

Proteasomes

breakdown and recycling of damaged or abnormal intracellular proteins

Mitochondria

Powerhouse of the cell, organelle that is the site of ATP (energy) production

Centrioles/Centrosomes

Centrioles
→ Made of microtubules arranged in nine groups of three
Centrosome
→ Cytoplasm that contains the perpendicular pairs
**active during cellular division (mitosis)

The Cell Cycle

series of events in which a cell grows, prepares for division, and divides to form two daughter cells
Includers Interphase & Mitotic (M) Phase

Phases of Interphase

First gap phase (G1)
→ Growth & normal metabolic roles

Synthesis phase (S)
→ DNA replication

Second gap phase (G2)
→ Growth & preparation for mitosis
→ DNA proofreading

Mitosis

part of eukaryotic cell division during which the cell nucleus divides

Phases of Mitosis

prophase, metaphase, anaphase, telophase

Prophase

Chromosomes become visable, nuclear envelop dissolves, spindle forms

Metaphase

Chromosomes line up in the middle of the cell

Anaphase

Phase of mitosis in which the chromosomes separate and move to opposite ends of the cell

Telophase

After the chromosome seperates, the cell seals off, Final Phase of Mitosis.

Cytokenesis

Division of cytoplasm, cleavage furrow develops end of anaphase/beginning of telophase, ultimately cell pinches into two identical daughter

Cytosol

Fluid portion of cytoplasm

Glycolipids (in Plasma Membrane)

Lipids that have carbohydrates attached to them, glucose (sugar) + phospholipid for cell signaling and recognition

Intracellular

within the cell

Extracellular

outside the cell