Cell Biology and Membrane Transport - UNIT 2 COURSE GUIDE

Ribosomes

Composed of rRNA and protein; synthesize proteins according to mRNA sequences.

Rough Endoplasmic Reticulum

Associated with ribosomes; aids in compartmentalization and protein synthesis.

Smooth Endoplasmic Reticulum

Functions include lipid synthesis and cellular detoxification.

Golgi Complex

Folds, chemically modifies, and packages proteins for trafficking.

Mitochondria

Double-membraned organelle where aerobic cellular respiration and ATP synthesis occur.

Lysosomes

Sac-like organelles containing hydrolytic enzymes for digestion and apoptosis.

Plant Vacuoles

Large vacuoles that maintain turgor pressure through water and nutrient storage.

Chloroplasts

Double-membraned organelles in plants and algae that serve as the site of photosynthesis.

Surface Area-to-Volume Ratio

Smaller cells have a higher ratio and more efficient material exchange.

Phospholipid Bilayer Orientation

Hydrophilic heads face outward; hydrophobic fatty acid tails face inward.

Fluid Mosaic Model

Framework of phospholipids embedded with movable proteins, steroids, and carbohydrates.

Selective Permeability

The hydrophobic interior of the plasma membrane restricts large polar molecules and ions.

Passive Transport

Movement of molecules down a concentration gradient without metabolic energy input.

Active Transport

Movement of molecules requiring metabolic energy, often against a concentration gradient.

Endocytosis

Process where the cell takes in large molecules by folding the membrane to form vesicles.

Facilitated Diffusion

Movement of molecules down a concentration gradient using channel or transport proteins.

Aquaporins

Specialized channel proteins that transport large quantities of water across membranes.

Osmosis

Movement of water from regions of high water potential to low water potential.

Sodium-Potassium Pump

Active transport mechanism utilizing ATP to maintain electrochemical gradients.

Endosymbiotic Theory

Theory that mitochondria and chloroplasts evolved from once free-living prokaryotic cells.

What is Chromatin?

A mixture of DNA and proteins that forms chromosomes inside the nucleus. The main function is to pack DNA tightly and control which genes are active.

What is a Chromosome?

A single, continuous package of highly condensed chromatin that forms a thread like structure. It ensures the precise replication and equal spread of DNA.

What is a Centriole?

A barrel-spread organelle made or microtubules found in pairs near the nucleus of animal cells. It organizes the mitotic spindle and pulls chromosomes apart during cell division

What is the Cell Wall?

A protective outer layer positioned just outside the cell membrane in plants, fungi etc. It provides structural support and shape.

What is a Eukaryote?

An organisms whose cells contain a true nucleus and organelles. The primary function is to isolate and organism complex biological processes.

What is a Prokaryote?

An organism that lacks a nucleus, and other specialized enclosed organelles. It survives and reproduces rapidly.

What are Ribosomes?

An organelle that is made of RNA and proteins found in the cytoplasm or attached to Rough ER. It translates genetic instructions into proteins?

What is Rough ER (Endoplasmic Reticulum)?

A network of folded, membrane bound sacs and tubules, that is studded with ribosomes on it’s outer surface, it folds, modifies, and transports proteins

What is Smooth ER (Endoplasmic Reticulum)?

A network of tubular membranes that lacks attached ribosomes, giving it a smooth outer appearance since it lacks attached ribosomes.

What is Plasmodesmata?

They are microscopic tunnels that drill directly through the tough cell walls of plant cells. They connect the cells so they can easily share food and water.

What is a Vesicle?

A tiny, fluid - filled sac enclosed by a lipid membrane that floats within the cytoplasm of a cell. It’s primary function is to transport and store materials.

What is a Central/Water Vacuole?

A massive membrane bound storage compartment that occupies most of the internal volume of a plant cell. It stores water, nutrients, and waste, while maintaining turgor pressure.

What is a Centrosome?

It’s located near the nucleus that serves as the main microtubule - organizing center of animal cells. It builds and guides the spindle fibers

What are Spindle Fibers?

A microscopic, thread like structure made of protein microtubules that forms during cell division. The primary function is to attach and physically pull the chromosomes apart.

What is the Cytoskeleton/Microtubules?

A dynamic network of protein filaments that span throughout a cell’s cytoplasm. It acts as a scaffold to provide shape and support.

What is a Lysosome?

A membrane bound organelle that contains digestive enzymes to break down waste materials and worn out cell parts. It recycles these materials to help the cell function properly and stay clean

What is a Nuclear Pore?

A tiny channel in the membrane that surrounds a cell’s nucleus. It controls the movement of molecules in and out of the nucleus.

What is the Mitochondrion?

A small part inside a cell that acts like a power plant. It breaks down food to make energy the cell can use.

What is the Chloroplast?

A specialized organelle found in plant and algae cells that conducts photosynthesis. It captures light energy from the sun and converts it into chemical energy in the form of sugar to feed the plant.

What is the Golgi Body/Apparatus?

A cell part that looks like a stack of flat, folded pouches. It gathers, changes, and packs proteins and fats so they can go to the right places inside or outside the cell.

What is the Nucleolus?

It is a distinct, round structure located inside the nucleus of a cell. It’s primary job is to produce and assemble ribosomes, which are the cell’s protein-making factories

What is the Peroxisome?

A small membrane - bound compartment found inside plant and animal cells. It’s primary jobs are to break down fatty acids for energy.

What specific type of ribosomes are found in prokaryotes, as well as chloroplasts and mitochondria?

70s Ribosomes

What is the mechanism of movement across cell surface membrane for the release of enzymes into the gut?

Bulk Transport (Endocytosis)

What is the mechanism of movement across cell surface membrane for a plant cell taking up water?

Osmosis

What is the mechanism of movement across cell surface membrane for calcium ions entering a nerve cell down a concentration gradient?

Facilitated Diffusion

What is the mechanism of movement across cell surface membrane for oxygen entering a red blood cell?

Simple Diffusion

What does the Endosymbiotic Theory state?

That the chloroplast and mitochondria evolved from an early prokaryotic cell engulfed by a larger cell

What are the 4 pieces of evidence that prove the Endosymbiotic Theory?

1. Chloro/Mito have a double membrane structure

2. Chloro/Mito have their own plasmid DNA (genes)

3. Both Contain 70s ribosomes

4. Binary Fission (Bacterial Cells SPLIT into 2 cells)