Biology Chapter: Cell Study and Theory

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Questions and Answers

What are the primary components of the plasma membrane?

Protein and cholesterol

Carbohydrates and proteins

Nucleic acids and phospholipids

Phospholipids and proteins (correct)

Which of the following best describes the term 'amphipathic' as it relates to cell membranes?

It is entirely hydrophobic.

It contains both hydrophilic and hydrophobic regions. (correct)

It contains only hydrophilic regions.

It is impermeable to all substances.

What structure is responsible for producing ATP in the mitochondria?

Matrix

Cell wall

Ribosome

Cristae (correct)

Which of the following correctly identifies the function of cilia?

Movement in airways Signup and view all the answers

What type of cell wall is commonly found in organisms living in volcanic vents?

Pseudomurine Signup and view all the answers

What is the role of chlorophyll in plants?

It absorbs sunlight for photosynthesis. Signup and view all the answers

What do thylakoid structures in chloroplasts collectively form?

Grana Signup and view all the answers

Which of the following statements about unicellular organisms is true?

They are made up of only one cell. Signup and view all the answers

What was the contribution of Zacharias Janssen in cell studies?

He invented the first compound microscope. Signup and view all the answers

Which of the following is NOT a criterion for an entity to be considered alive?

Reproduction Signup and view all the answers

What did Rudolf Virchow contribute to the understanding of cells?

He stated that all cells arise from pre-existing cells. Signup and view all the answers

Why are viruses considered non-living entities?

They cannot reproduce independently. Signup and view all the answers

Which of the following statements about cells is true?

The cell is the basic unit of organization in living things. Signup and view all the answers

Who was the first to see living microscopic organisms?

Antonie van Leeuwenhoek Signup and view all the answers

Which statement about bacteria is correct?

Bacteria are common pathogens found in various environments. Signup and view all the answers

What aspect of cell theory was contributed by Theodore Schwann?

All animals are made of cells. Signup and view all the answers

Study Notes

How Were Cells Studied?

Cell study spanned generations
Zacharias Janssen, a spectacle maker, produced the first compound microscope (two lenses).
Robert Hooke used a light microscope to examine thin slices of plant tissue (cork).
Antonie van Leeuwenhoek first observed living microorganisms.
Robert Brown identified the central structure of plant cells.
Matthias Schleiden determined all plants consist of cells.
Theodore Schwann postulated that all animals are made of cells.

Disproving Spontaneous Generation

Francesco Redi's experiments disproved spontaneous generation.
Rudolf Virchow's work revised the cell theory, stating that all cells originate from preexisting cells.

Updated Cell Theory

A cell is the basic unit of life.
All organisms are made up of cells.
All cells come from preexisting cells.
To be considered alive, an entity needs information, metabolism, and a membrane.
Viruses contain genetic material but lack metabolism and are, therefore, not considered living.

Parts of the Cell

Plasma membrane, also called plasmalemma, is a lipid bilayer that selectively regulates passage between internal and external environments.
The plasma membrane controls movement of materials in and out of the cell.

Cell Membrane: Structure and Fluidity

The cell membrane is a lipid bilayer composed of phospholipids.
Phospholipids have hydrophilic heads and hydrophobic tails that arrange to form a bilayer with tails facing inward.
Cholesterol and proteins are also embedded in the membrane, affecting fluidity.
The cell membrane's fluidity depends on the hydrocarbon tails (saturated or unsaturated) and cholesterol content.

Cell Membrane: Protein Structures

Some proteins span the entire membrane (transmembrane) and some sit on one side (peripheral).
Transmembrane proteins help transport substances across the membrane.

Nucleus and Nuclear Envelope

The nucleus is the cell's control center, containing DNA.
The nuclear envelope is a double membrane enclosing the nucleus, perforated by pores that allow RNA to exit.
The nucleolus is a nonmembranous structure that produces ribosomes.

Cell Composition: DNA/ Chromosomes

DNA is found within the nucleus, organized into chromosomes.
Chromosomes contain genetic information.
Chromosomes carry genetic instructions for building and maintaining cells.

Endomembrane System: Smooth and Rough Endoplasmic Reticulum (ER)

Smooth ER lacks ribosomes and is involved in lipid synthesis, detoxification, and calcium storage.
Rough ER has ribosomes and is involved in protein synthesis and modification.

Ribosomes

Ribosomes are responsible for protein synthesis.
They are not membrane-bound organelles and are made up of small and large subunits.

Cell Composition: Endomembrane System: Golgi Bodies

The Golgi body modifies and packages proteins.
Golgi bodies are involved in vesicle formation and transportation.

Cell Composition: Endomembrane System: Lysosomes

Lysosomes contain enzymes that digest cellular waste and invaders.
They function in recycling and breakdown of cellular components.

Cell Composition: Endomembrane System: Vacuoles

Vacuoles are membrane-bound sacs used for storage and maintaining the shape of the cell.

Cell Composition: Cytoskeleton

The cytoskeleton gives structure and shape to the cell.
It supports cell movement and organelle movement.
It is made up of microtubules, intermediate filaments and actin filaments.

Cell Composition: Extracellular Components: Cilia and Flagella

Cilia and flagella facilitate movement.
Cilia are short, hair-like extensions used for moving substances on cell surfaces.
Flagella are whip-like structures found in sperm cells, used for movement.

Cell Composition: Extracellular Components: Cell Walls

Cell walls are found in plants, fungi, and some protists.
They provide support and protection to the cell.
Plant cell walls are made of cellulose.

Cell Composition: Organelle: Mitochondria

Mitochondria are the powerhouses of the cell (energy production).
They are surrounded by a double membrane, with inner folds called cristae.
The matrix is the fluid-filled space inside the inner membrane.

Cell Composition: Organelle: Plastids

Plastids are organelles involved in storage and synthesis.
Chloroplasts are the site of photosynthesis.
Common examples are chloroplasts, amyloplasts, chromaoplasts, and elaioplasts.

Cell Composition: Organelle: Ribosomes

Ribosomes are involved in protein synthesis.
They are not membrane-bound organelles.
They consist of two subunits

Prokaryotes vs. Eukaryotes

Prokaryotic cells lack a membrane-bound nucleus and membrane-bound organelles.
Eukaryotic cells have a nucleus and membrane-bound organelles.
These differences relate to complexity and size.

Volume and Surface Area

Cells have a limited size because a larger volume requires a larger surface area to function efficiently.
If the volume increases beyond the surface area capacity, the cell will not be able to function and will likely burst.

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Description

This quiz explores significant milestones in cell study, including key figures like Robert Hooke and Antonie van Leeuwenhoek. It also examines the evolution of cell theory and its implications in biology. Test your understanding of how cells were studied and the disproving of spontaneous generation!