CELL ORGANELLES, MEMBRANES, AND TRANSPORT (PG. 55-60)

What are the 2 types of cells?

Prokaryotic = simple cells

Eukaryotic = more complex cells

👉 Biggest difference: eukaryotic cells have a nucleus and membrane-bound organelles; prokaryotic cells don’t.

What do ALL cells have?

Every cell has:

DNA

Ribosomes

Cytosol

Plasma membrane

🧠 ALL = DNA + ribosomes + cytosol + membrane

Where is DNA in a prokaryotic cell?

The DNA is in the nucleoid region.

It isn’t inside a nucleus because prokaryotes don’t have a nucleus.

What is a plasmid?

A small circle of extra DNA found in some bacteria.

🧠 Think: little extra DNA circle.

How are prokaryotic and eukaryotic DNA different?

Prokaryotic: usually circular DNA → nucleoid

Eukaryotic: linear chromosomes → nucleus

What do ribosomes do?

They make proteins.

🧠 Ribosome = protein maker

What are the two parts of a ribosome?

A large subunit and a small subunit.

The sizes differ between prokaryotic and eukaryotic ribosomes.

What are ribosomes made of?

Protein + rRNA (ribosomal RNA).

And they’re NOT surrounded by a membrane.

What are the ribosome sizes?

A large subunit and a small subunit

🦠 Prokaryotic = 70S
🧬 Eukaryotic = 80S

70S: 50S + 30S
80S: 60S + 40S

🚨 Don’t accidentally say 50 + 30 = 80. The whole prokaryotic ribosome is 70S.

What is the ER?

The endoplasmic reticulum (ER) is a network of membranes inside the cell.

There are two types:

Rough ER

Smooth ER

What’s the difference between rough ER and smooth ER?

Rough ER: has ribosomes attached → helps make proteins.

Smooth ER: no ribosomes attached.

🧠 ROUGH = has bumps (ribosomes).

What does the Golgi apparatus do?

It changes, sorts, and packages proteins so they can be sent where they need to go.

🧠 Golgi = post office for proteins 📦

What is the Golgi lumen?

The inside space of a Golgi cisterna.

🧠 Lumen = inside space.

What are cisternae?

The flattened sacs that make up the Golgi.

🧠 If you see a stack of flat pancakes → cisternae/Golgi.

What is a vesicle?

A tiny membrane bubble/sac that carries things around the cell.

🧠 Vesicle = delivery bubble 📦

What are lysosomes?

Little sacs filled with enzymes that break things down.

They can break down:

Macromolecules

Old/worn-out cell parts

Bacteria and viruses

🧠 Lysosome = cell’s recycling/digestion center ♻

Why is the lysosome membrane important?

It keeps the powerful digestive enzymes contained inside the lysosome instead of letting them freely spread through the cell.

What does a vacuole do?

It is like a storage container.

It can store:

Water 💧

Food

Waste

It can also help with water regulation.

Why are vacuoles important in plant cells?

A large vacuole fills with water and creates turgor pressure, which helps keep the plant cell firm and supported.

🧠 Water in vacuole → pressure → plant stays firm.

What do mitochondria do?

They help the cell make energy (ATP) through cellular respiration.

🧠 Mitochondria = energy makers ⚡

What are cristae?

The folds of the inner mitochondrial membrane.

Why are they important?

👉 They give the mitochondrion more surface area for energy-producing processes.

🧠 Cristae = folds = more space.

What is the mitochondrial matrix?

The fluid-filled inside of the mitochondrion.

The Krebs cycle happens there.

🧠 Matrix = inside of mitochondrion.

What should I recognize in a mitochondrion diagram?

Know these:

Outer membrane = outside

Inner membrane = inside membrane

Intermembrane space = space between membranes

Cristae = folds

Matrix = inside fluid

ATP synthase = helps make ATP

Ribosomes = inside mitochondria

What are chloroplasts?

Chloroplasts are structures in plants and photosynthetic algae that carry out photosynthesis.

🧠 Chloroplast = photosynthesis 🌱

What are thylakoids, grana, and stroma?

🥞 Thylakoid = ONE pancake-like sac

🥞🥞🥞 Granum = stack of thylakoids

🌊 Stroma = fluid surrounding the grana

🧠 One pancake = thylakoid. Stack = granum. Liquid = stroma.

Where do the reactions of photosynthesis happen?

☀ Light-dependent reactions → thylakoid membranes

🌱 Light-independent reactions → stroma

🚨 This one is VERY worth memorizing.

What do mitochondria and chloroplasts have in common?

Both have:

Double membranes

Their own DNA

Their own ribosomes

🧠 They’re both a little different from most organelles because they have their own DNA and ribosomes.

What is a centrosome?

A structure in animal cells that helps organize microtubules.

During cell division, these help form spindle fibers.

🧠 Centrosome → microtubules → spindle fibers → cell division

What is an amyloplast?

A structure in plant cells that stores starch.

🧠 Amyloplast = starch storage 🌱🥔

It’s especially common in roots and tubers, like potatoes.

What is Peroxisome?

Peroxisome → helps break down/oxidize molecules and toxins.

What is the Nucleolus?

Nucleolus → makes/assembles ribosomes inside the nucleus.

What is Cytoskeleton?

Cytoskeleton → helps the cell keep its shape and helps move things around inside the cell.