Cell Organelles – General Biology I (Lesson 3) Flashcards

Flashcards covering cell organelles, their membrane-bound status, and functions from the lecture notes (Lesson 3).

What are the three postulates of the cell theory?

1) All living things are composed of cells. 2) The cell is the basic unit of structure and function in living things. 3) New cells arise from pre-existing cells.

What is the difference between membrane-bound and non-membrane-bound organelles?

Membrane-bound organelles are enclosed within a membrane (lipid bilayer); non-membrane-bound organelles lack a surrounding membrane.

What is the nucleus and its role in the cell?

A double-membrane organelle that acts as the brain of the cell: it controls all cellular activities and stores the cell's DNA.

What is the cell membrane (plasma membrane) and its function?

A semi-permeable barrier that protects the cell and regulates movement of molecules into and out of the cell; also called the gatekeeper.

What is the composition of the cell membrane?

Phospholipid bilayer forming two layers with embedded protein channels that facilitate transport.

What is the cytoplasm and what is the cytosol?

Cytoplasm is the jelly-like fluid inside the cell; cytosol is the liquid portion where many chemical reactions occur and which helps secure organelles in place.

What is the mitochondrion and its function?

Powerhouse of the cell; generates energy as ATP through cellular respiration; double-membrane organelle.

What is a ribosome and its function?

Protein factory of the cell; site of protein synthesis; composed of RNA and protein.

What is the Endoplasmic Reticulum (ER) and its two types?

A network of membranes that facilitates movement of proteins and lipids inside the cell; Rough ER has ribosomes and synthesizes proteins; Smooth ER lacks ribosomes and synthesizes lipids.

What is Rough Endoplasmic Reticulum (RER) and its function?

Portion of ER attached to the nuclear envelope with ribosomes; primarily involved in protein synthesis.

What is Smooth Endoplasmic Reticulum (SER) and its function?

Portion of ER that is ribosome-free, giving it a smooth appearance; primarily involved in lipid synthesis.

What is the Golgi apparatus and its function?

Packaging center; packages modified proteins and lipids into vesicles for transport to other parts of the cell or for secretion outside the cell.

What is a lysosome and its role in the cell?

Suicidal bag; digestive organelle with hydrolytic enzymes responsible for cellular digestion and recycling.

What is a peroxisome and its function?

Detoxifier; contains oxidative enzymes that detoxify harmful substances; can generate and remove hydrogen peroxide.

What enzyme do peroxisomes contain to decompose hydrogen peroxide?

Catalase; decomposes hydrogen peroxide into water or oxidizes another compound.

What is a vacuole and its function?

Storage tank of the cell; stores water, nutrients, and waste; central vacuoles in plants maintain turgor pressure.

What is the cytoskeleton and its role?

Skeleton of the cell; network of protein fibers providing structural support and shape.

What are centrioles and what is their function?

Assist the nucleus during cell division; form spindle fibers and basal bodies; located in centrosomes; present in human/animal cells.

What is a chloroplast and its function?

Cell’s solar panel; site of photosynthesis; double-membrane organelle containing chlorophyll; gives plants their green color.

What is the cell wall and where is it found?

Protective barrier providing structural support; typically found in bacteria, plants, and fungi.

Name some membrane-bound organelles.

Nucleus; Cell membrane; Mitochondria; Golgi body; Vesicles (Lysosomes, Peroxisomes, Vacuoles); Chloroplast.

Name some non-membrane-bound organelles.

Cytoplasm; Cytoskeleton; Ribosomes; Centrioles; Cell wall.

What are vesicles and which organelles are included under vesicles in the membrane-bound category?

Small membrane-bound sacs that transport, store, or digest substances; include lysosomes, peroxisomes, and vacuoles.