IB Biology Topic A2.2.5 Prokaryote Cell Structure Revision Notes (SL/HL)

IB Biology Topic A2.2.5 Prokaryote Cell Structure Revision Notes (SL/HL) | RevisionDojo

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A Prokaryote Runs Every Life Process in One Open Compartment

Definition

Prokaryote

A prokaryote is a single-celled organism that lacks a nucleus and membrane-bound organelles. Its genetic material is found in a single, circular DNA molecule located in the nucleoid region of the cell.

The Cell Wall Gives Shape and Protection

Definition

Cell wall

The cell wall is a rigid, protective layer located outside the plasma membrane of certain cells, including prokaryotes, plants, fungi, and some protists. It provides structural support, protection, and shape to the cell.

The cell wall is sturdy because of a thick layer of peptidoglycan, a polymer of sugars and amino acids that forms a rigid mesh.
This mesh gives the cell its shape.
It also acts as a protective barrier against environmental stresses.

Note

Gram-positive bacteria stain purple during Gram staining because their thick peptidoglycan layer retains the crystal violet dye.

The Plasma Membrane Controls What Enters and Leaves

Definition

Plasma membrane

The plasma membrane is the thin, flexible boundary that surrounds a cell, separating its internal environment from the external surroundings. It is composed of a phospholipid bilayer with embedded proteins, cholesterol, and carbohydrates.

The plasma membrane sits just beneath the cell wall.
It carries out several critical functions.
1. Transporting nutrients and waste: it takes in nutrients such as glucose and expels waste products.
2. Maintaining homeostasis: it regulates ion concentrations to keep the internal environment stable.
3. Energy production: it is the site of ATP production during respiration, since prokaryotes lack mitochondria.

Tip

The plasma membrane is fluid and dynamic, letting proteins move and adapt to the cell's needs.

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Definition

Paywall

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Note

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Excepteur sint occaecat cupidatat non proident

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Tip

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Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

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A Prokaryote Runs Every Life Process in One Open Compartment

Definition

Prokaryote

The Cell Wall Gives Shape and Protection

Definition

Cell wall

The cell wall is sturdy because of a thick layer of peptidoglycan, a polymer of sugars and amino acids that forms a rigid mesh.
This mesh gives the cell its shape.
It also acts as a protective barrier against environmental stresses.

Note

Gram-positive bacteria stain purple during Gram staining because their thick peptidoglycan layer retains the crystal violet dye.

The Plasma Membrane Controls What Enters and Leaves

Definition

Plasma membrane

The plasma membrane sits just beneath the cell wall.
It carries out several critical functions.
1. Transporting nutrients and waste: it takes in nutrients such as glucose and expels waste products.
2. Maintaining homeostasis: it regulates ion concentrations to keep the internal environment stable.
3. Energy production: it is the site of ATP production during respiration, since prokaryotes lack mitochondria.

Tip

The plasma membrane is fluid and dynamic, letting proteins move and adapt to the cell's needs.

Definition

Paywall

(on a website) an arrangement whereby access is restricted to users who have paid to subscribe to the site.

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Note

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam quis nostrud exercitation.

Excepteur sint occaecat cupidatat non proident

Tip

Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

A - Unity and Diversity9 subtopics

B - Form and Function10 subtopics

C - Interaction and Interdependence9 subtopics

D - Continuity and Change12 subtopics

IB Biology Topic A2.2.5: Prokaryote Cell Structure Notes

A - Unity and Diversity9 subtopics

B - Form and Function10 subtopics

C - Interaction and Interdependence9 subtopics

D - Continuity and Change12 subtopics

A Prokaryote Runs Every Life Process in One Open Compartment

The Cell Wall Gives Shape and Protection

The Plasma Membrane Controls What Enters and Leaves

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account

A Prokaryote Runs Every Life Process in One Open Compartment

The Cell Wall Gives Shape and Protection

The Plasma Membrane Controls What Enters and Leaves

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account