KIN 223 CHAPTER 4 LESSON OBJECTIVES

Light Microscope

Light Microscope

Produces two-dimensional images by passing light through a stained specimen.

Electron Microscope

Uses beams of electrons to illuminate a specimen stained with heavy metal.

Transmission Electron Microscope

Directs an electron beam through a thin section of a specimen to create a two-dimensional image.

Scanning Electron Microscope

Uses an electron beam across the surface of a specimen to generate a three-dimensional digital image.

Human Cell Size

Most human cells range from 1 micrometer to 100 nanometers in diameter.

Cell Shapes

Cells exhibit various shapes that support different functions, such as irregular (dendrite), biconcave (red blood cells), cuboidal (kidney tubule cells), columnar (intestinal lining cells), spherical (cartilage cells), and cylindrical (skeletal muscle cells).

Plasma Membrane

The outer barrier that separates the internal contents of the cell from the interstitial fluid.

Nucleus

The largest structure within the cell, enclosed by a nuclear envelope.

Cytoplasm

All cellular contents located between the plasma membrane and the nucleus.

Membrane-bound Organelles

Enclosed by a membrane, examples include the endoplasmic reticulum, Golgi apparatus, lysosomes, peroxisomes, and mitochondria.

Non-membrane-bound Organelles

Not enclosed within a membrane, examples include ribosomes, centrosomes, proteasomes, and cytoskeleton.

Cell Inclusions

Clusters of a single type of molecule, not considered organelles.

Cell Functions

Maintain integrity and shape, obtain nutrients, and dispose of wastes.

Phospholipids

Form bilayers of the plasma membrane.

Cholesterol

Strengthens and stabilizes the membrane at temperature extremes.

Glycolipids

Lipids with attached carbohydrate groups.

Integral Proteins

Embedded within and extend across the phospholipid bilayer.

Peripheral Proteins

Loosely attached to the membrane's external or internal surfaces.

Transport Proteins

Regulate movement of substances across the plasma membrane.

Cell Surface Receptors

Bind specific molecules (ligands) to initiate cellular responses.

Identity Markers

Communicate cell identity to the immune system.

Enzymes

Catalyze chemical reactions by lowering activation energy.

Anchoring Sites

Secure the cytoskeleton to the plasma membrane.

Cell-adhesion Proteins

Facilitate cell-to-cell attachments.

Diffusion

Random movement of molecules down a concentration gradient.

Simple Diffusion

Movement of small, non-polar solutes through the phospholipid bilayer.

Facilitated Diffusion

Requires assistance from membrane proteins for charged or polar solutes.

Osmosis

Passive movement of water through a semipermeable membrane.

Tonicity

Changes in cell volume due to water movement across the plasma membrane.

Active Transport

Movement of solutes against their concentration gradient.

Primary Active Transport

Uses ATP directly to move substances up their concentration gradient.

Secondary Active Transport

Uses the movement of one substance down its gradient to move another substance up its gradient.

Vesicular Transport

Movement of large substances across the plasma membrane using membrane-bound sacs.

Exocytosis

Secretion of large substances from the cell.

Endocytosis

Uptake of large substances from the external environment into the cell.

Phagocytosis

Cellular eating, engulfing large particles.

Pinocytosis

Cellular drinking, internalizing interstitial fluid.

Receptor-mediated Endocytosis

Uses receptors to bind specific molecules for uptake.

Resting Membrane Potential (RMP)

The membrane potential when a cell is at rest.

Ion Distribution

Unequal distribution of ions across the plasma membrane establishes RMP.

Role of K+

Potassium ions exit the cell, creating a negative charge inside the membrane.

Role of Na+

Sodium ions enter the cell, but the membrane is mostly impermeable to Na+ at rest.

Direct Contact Communication

Cells communicate through direct contact, such as during fertilization or tissue repair.

Channel-linked Receptors

Allow ion passage in response to ligand binding.

Enzymatic Receptors

Function as protein kinases to add phosphate groups to other enzymes.

G Protein-coupled Receptors

Activate protein kinases indirectly through G proteins.

Membrane-bound Organelles

Surrounded by membranes, including the endoplasmic reticulum and Golgi apparatus.

Endoplasmic Reticulum

Interconnected membrane network involved in protein and lipid synthesis.

Golgi Apparatus

Composed of membranous sacs, involved in modifying and packaging proteins.

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