Biology 1: Cell Biology and Organelles

Practice questions covering the history of cell biology, cell theory, membrane-bound and non-membrane-bound organelles, and the differences between prokaryotic, eukaryotic, plant, and animal cells.

What is the definition of cell biology, also known as "cytology"?

It is the study of cell structure and function, revolving around the concept that the cell is the fundamental unit of life.

Who first introduced the term "cell" and in what year?

Robert Hooke introduced the term in 1667.

What did Robert Hooke observe when examining thin slices of cork?

He saw closely-packed little boxes with thick walls, which were actually the walls of dead plant cells.

Who was the first to observe red blood cells, sperms, and single-celled organisms in pond water?

The Dutch inventor Antoine Van Leeuwenhoek in 1674.

What was Robert Brown's contribution to cell biology in 1831?

He discovered the nucleus and theorized it is a fundamental and constant component of the cell.

What name did Felix Dujardin give to the internal substance of living cells in 1835?

Sarcode.

Who coined the term "protoplasm" for the colloidal substance currently known as cytoplasm?

Jan Evangelista Purkinje.

What was the conclusion of Matthias Schleiden in 1838?

He stated that all plants are composed of cells.

What did Theodore Schwann conclude in 1839?

He concluded that all animals are composed of cells.

What does the phrase "Omnis cellula e cellula," stated by Rudolf Virchow in 1855, mean?

All cells originate from other preexisting cells through cell division.

What are the three core principles of the Cell Theory?

1. Cell is the basic unit of structure and organization in organisms; 2. All living organisms are composed of cells; 3. Cell arise from pre-existing cells.

How are the cell walls of plants, fungi, and bacteria composed differently?

Plants are made of Cellulose, Fungi are made of Chitin, and Bacteria are made of Peptidoglycan.

Why is the cell membrane described as the "gatekeeper of the cell"?

It is semi-permeable, meaning it allows only some substances to pass through and controls substances entering or leaving the cell.

How do Singer & Nicolson describe the structure of the cell membrane?

As a "fluid mosaic."

What three components make up the protoplasm of a cell?

1. Cell membrane, 2. Nucleus, and 3. Cytoplasm.

What is the "cytoplasm" defined as in the transcript?

The part of the protoplasm between the cell surface membrane and the nucleus, consisting of organelles and a jelly-like substance called "cytosol."

Why is the nucleus referred to as the "control center of the cell"?

It controls cell activities such as cell growth, the repair of worn-out parts, and cell division, and it contains DNA.

What is the function of the nucleolus?

It is the site of ribosome biogenesis for protein synthesis.

What is chromatin?

A complex of DNA and proteins called "histones" that forms chromosomes within the nucleus.

What is the difference between the Rough ER and the Smooth ER?

Rough ER has ribosomes attached and focuses on protein synthesis, while Smooth ER lacks ribosomes and focuses on lipid synthesis.

What are the primary functions of the Golgi apparatus?

Waste secretion and intracellular transport.

Why are lysosomes known as "suicide bags"?

They contain hydrolytic enzymes used to digest food and break down the cell when it dies.

What is apoptosis?

The death of cells that occurs as a normal and controlled part of an organism's growth or development.

What is the function of the chloroplast?

To conduct photosynthesis by absorbing sunlight with water and carbon dioxide to produce food for the plant.

Which organelle is the "powerhouse" of the cell and what does it produce?

The mitochondrion, which converts oxygen and nutrients into ATP.

Why is the ribosome NOT considered an organelle in this lecture?

Because it lacks a membrane covering.

What are the three locomotive structures cells use for movement?

1. Cilia, 2. Flagella, and 3. Pseudopodia.

What does the term "Pseudopodia" mean and what is its function?

It means "false foot" (Pseudo = false, Podia = foot) and is used for movement and ingestion.

Contrast the size and DNA of eukaryotic versus prokaryotic cells.

Eukaryotic cells are larger than $10\,\text{micrometres}$ with linear DNA in a nucleus; prokaryotic cells are smaller than $10\,\text{micrometres}$ with ring-form DNA free in the cytoplasm.

How does food storage differ between animal cells and plant cells?

Animal cells store food as glycogen, while plant cells store food as starch.