Biology 101: Cell Structure & Function

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Questions and Answers

What is the primary function of the nuclear envelope?

To package DNA into chromosomes

To store genetic information only

To synthesize ribosomal subunits

To provide a selective barrier between the nucleus and cytoplasm (correct)

Which component of the nucleus is responsible for creating ribosomal subunits?

Nucleolus (correct)

Nuclear envelope

Chromatin

Nuclear pores

How is chromatin different from chromosomes?

Chromatin is packaged by histones

Chromatin is a higher order of DNA organization

Chromatin is a more relaxed form of DNA organization (correct)

Chromatin is denser and more complex

What is the role of nuclear pores?

To allow exchange of molecules between the nucleus and cytoplasm Signup and view all the answers

What is NOT a function of the nucleus?

Storing ATP for energy production Signup and view all the answers

What is the primary function of mitochondria within a cell?

To generate adenosine triphosphate (ATP) Signup and view all the answers

Which structure is continuous with the nuclear membrane in animal cells?

Rough endoplasmic reticulum (ER) Signup and view all the answers

What role do Golgi bodies play in the cell?

They put finishing touches on proteins and lipids Signup and view all the answers

What is a unique feature of mitochondrial DNA (mtDNA)?

It is circular and separate from nuclear DNA Signup and view all the answers

Which of the following structures is found only in plant cells?

Plastids Signup and view all the answers

What do cristae in mitochondria do?

They increase surface area for metabolic processes Signup and view all the answers

Which of the following structures is part of the cytomembrane system?

Endoplasmic reticulum Signup and view all the answers

What is the primary purpose of vesicles in cellular function?

To transport materials within the cell Signup and view all the answers

What did Robert Hooke contribute to the field of biology?

He observed and described cells in cork. Signup and view all the answers

Which of the following statements is NOT part of the Cell Theory?

Cells are capable of photosynthesis. Signup and view all the answers

What characterizes a prokaryotic cell?

Simple structure without membrane-bound organelles. Signup and view all the answers

What is the primary function of lysosomes in a cell?

Destroying pathogens and worn-out cells Signup and view all the answers

What is the primary function of the cell membrane?

Regulating transport of materials entering and exiting the cell. Signup and view all the answers

Which of the following describes a function of the plant cell wall?

Providing rigidity and shape Signup and view all the answers

Which components make up the Fluid Mosaic Model of the plasma membrane?

Phospholipids, proteins, cholesterol, and carbohydrates. Signup and view all the answers

What components make up the cytoskeleton?

Microtubules, microfilaments, intermediate filaments Signup and view all the answers

What feature of phospholipids contributes to the structure of the cell membrane?

Hydrophilic heads point outward while hydrophobic tails form the interior. Signup and view all the answers

Which of the following correctly describes chloroplasts?

They contain their own DNA and help in photosynthesis. Signup and view all the answers

Which of the following scientists is associated with naming the nucleus?

Robert Brown. Signup and view all the answers

What role does the cytoplasm play in a cell?

It provides a medium for metabolic reactions. Signup and view all the answers

What separates the stroma from the intermembrane space in chloroplasts?

Inner membrane Signup and view all the answers

What is the role of the thylakoid system within the chloroplast?

Conducting photosynthesis by capturing light Signup and view all the answers

How do lysosomes contribute to cell death in certain conditions?

By releasing enzymes that digest cellular components Signup and view all the answers

Which of the following functions is NOT attributed to the cell wall in plant cells?

Facilitating cell apoptosis Signup and view all the answers

Study Notes

Early Discoveries in Cell Biology

Mid 1600s: Robert Hooke first observed and described cells in cork.
Late 1600s: Antonie van Leeuwenhoek discovered microorganisms using a microscope.
1820s: Robert Brown identified and named the nucleus in plant cells.

Development of Cell Theory

Key contributors: Matthias Schleiden, Theodor Schwann, Rudolf Virchow.
Cell Theory includes:
- All organisms are made of one or more cells.
- The cell is the smallest unit possessing the properties of life.
- Life continuity arises from cell growth and division.

Characteristics of Cells

Smallest unit of life; can survive independently or potentially do so.
Highly organized for metabolic functions.
Capable of sensing and responding to the environment.
Has reproductive potential.

Basic Structures of Cells

All cells consist of:
- Plasma membrane
- Nucleus/DNA
- Cytoplasm
Two main types: prokaryotic and eukaryotic.

Cell Membrane and Fluid Mosaic Model

The plasma membrane separates the cell's interior from the external environment and is semipermeable.
Composed of a lipid bilayer, proteins, cholesterol, and carbohydrates creating a fluid structure.
Phospholipids with hydrophilic heads and hydrophobic tails contribute to membrane functionality.

Nucleus Structure and Function

Composed of:
- Nuclear envelope with lipid bilayers and DNA attachment sites.
- Nucleolus for ribosomal subunit production.
- Nuclear pores for molecular exchange between nucleus and cytoplasm.
- Chromatin (less compact DNA) and chromosomes (packed DNA).
Functions:
- Controls cellular functions and synthesis of structural proteins.
- Houses genetic information and facilitates DNA organization before cell division.

Cytoplasm Components

Includes the cytomembrane system, mitochondria, lysosomes (in animals), and plant-specific structures like the cell wall and plastids.
Endoplasmic Reticulum (ER):
- Rough ER contains ribosomes for protein synthesis.
- Smooth ER is involved in lipid synthesis.

Golgi Bodies

Modify and package proteins and lipids from ER for transport.
Materials exit in vesicles.

Mitochondria

Double-membrane structure with distinct compartments: outer membrane, inner membrane with cristae, and matrix.
Cristae increase surface area for metabolic reactions.
Contains its own DNA, playing a critical role in energy production (ATP).

Lysosomes

Contains hydrolytic enzymes responsible for breaking down pathogens and recycling worn-out cell components.
Known as "suicide bags" due to the risk of cell destruction if they burst.

Cell Wall (Plant Cells)

Offers shape, strength, rigidity, and protection against mechanical stress.
Controls cell expansion and prevents water loss.
Functions as a barrier between cellular components and the environment.

Cytoskeleton

Present in all eukaryotic cells; maintains cell shape and organization.
Facilitates organelle movement and, in some cases, cell motility.
Comprises microtubules, microfilaments, and intermediate filaments.

Chloroplasts

Organelles containing chlorophyll for photosynthesis.
Capture sunlight energy, converting it into usable forms while releasing oxygen.
Contain their own genetic material, making them semi-autonomous; capable of producing proteins and membranes needed for their function.

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Description

This quiz covers key concepts in cell structure and function as outlined in BIO-101, Lecture 03. Explore early discoveries in cell biology by Robert Hooke, Antonie van Leeuwenhoek, and the development of cell theory by Schleiden and Schwann. Test your knowledge and understanding of the foundational elements of biology.