A2.2 Cell Structures and Processes [IB Biology SL/HL]

What is a key feature that distinguishes prokaryotic cells from eukaryotic cells?

Prokaryotic cells lack a nucleus and are non-compartmentalized.

What are 70S ribosomes and where are they found?

70S ribosomes are smaller ribosomes found in prokaryotic cells.

What is the difference between the DNA in prokaryotes and eukaryotes?

Prokaryotic DNA is not enclosed in a nucleus and is often referred to as naked DNA, while eukaryotic DNA is enclosed in a nucleus and associated with histone proteins.

What is the function of the large central vacuole in plant cells?

The large central vacuole stores water and helps maintain turgor pressure in plant cells.

What are the main functions all living organisms must perform according to the mnemonic MR SHANG?

Metabolism, Reproduction, Sensitivity, Homeostasis, Excretion, Nutrition, Growth.

What do cilia do in Paramecium?

Cilia assist in movement and help the organism respond to stimuli.

What is the main characteristic of eukaryotic cells?

Eukaryotic cells have membrane-bound organelles, including a nucleus.

What type of cells lack a cell wall?

Animal cells lack a cell wall.

What types of organisms are classified as unicellular?

Organisms made up of only one cell.

How do skeletal muscle cells differ from typical cells?

Skeletal muscle cells are multinucleated, meaning they contain more than one nucleus.

What is a defining feature of plant cells visible under electron micrographs?

Plant cells often have a rigid geometric shape due to the presence of a cell wall.

How do contractile vacuoles function in unicellular organisms?

They help maintain homeostasis by removing excess water.

What example of an exception to the cell theory involves red blood cells in humans?

Red blood cells lack a nucleus and consequently do not have DNA.

What are flagella and where are they found?

Flagella are whip-like projections that assist in movement, found in organisms like Chlamydomonas.

What types of structures do eukaryotic cells contain that prokaryotic cells do not?

Eukaryotic cells contain membrane-bound organelles and a nucleus.

What are the two main categories of cells?

Prokaryotic cells and eukaryotic cells.

What is homeostasis in the context of living organisms?

Homeostasis is the ability of an organism to maintain stable internal conditions regardless of external changes.

What is the difference in the structure of DNA between prokaryotes and eukaryotes?

In eukaryotes, DNA is organized into chromosomes and associated with histones; in prokaryotes, it is typically circular and not associated with histones.

How do you identify a prokaryotic cell in a micrograph?

Look for the absence of membrane-bound organelles and the presence of a single circular DNA structure.