Cell Structure & Function: Key Concepts for Biology Students

Who was the first to visualize cells with a microscope?

Leeuwenhoek

What term did Robert Hooke coin while examining cork?

Cell

What did Schwann and Schleiden propose about cells in the late 1830s?

Cells are the building blocks of all living things.

What principle did Rudolf Virchow establish in 1850?

All cells arise from pre-existing cells.

What are the three principles of Cell Theory?

1. All organisms are made of cells. 2. All life functions occur within cells. 3. All cells come from pre-existing cells.

What type of microscope can see general cell structure?

Light microscope

What is the function of an electron microscope?

To reveal internal details of cells with much higher resolution.

What are the four traits shared by all cells?

1. Plasma membrane 2. DNA 3. Cytoplasm 4. Ribosomes

What defines eukaryotic cells?

Membrane-bound nucleus and organelles.

What is the structure of the cell membrane?

Phospholipid bilayer with embedded proteins.

What is the function of ribosomes?

To read transcribed RNA and build proteins.

What is the primary role of mitochondria?

To produce ATP, the energy currency of the cell.

What does the Endoplasmic Reticulum (ER) do?

It is involved in protein and lipid synthesis.

What is the function of the Golgi Apparatus?

To modify, sort, and package proteins for their final destination.

What is the role of lysosomes?

To break down and recycle unneeded cellular components.

What is autophagy?

The process where a cell sends its own proteins/organelles to lysosomes for degradation.

What are the three types of cytoskeletal elements?

1. Microfilaments 2. Microtubules 3. Intermediate filaments

What is the function of cilia?

To provide movement, such as moving mucus in the respiratory tract.

What is the extracellular matrix (ECM)?

A mesh network of proteins and carbohydrates outside the cell that adds structural strength to tissues.

What is collagen?

The most abundant protein in the extracellular matrix.

What is the function of the nucleolus?

It is the site of ribosome assembly within the nucleus.

What is the significance of the endosymbiotic theory?

It suggests that mitochondria originated from free-living bacteria engulfed by early eukaryotic cells.

What is the structure of chromatin?

DNA wrapped around histones, coiling further to form condensed chromosomes.

What is the function of microvilli?

To increase surface area for absorption, especially in the digestive tract.

What is the role of the centrosome?

It is the microtubule organizing center and plays a key role in mitosis.

What is the primary function of a light microscope?

To see general cell structure.

What does an electron microscope reveal?

Internal detail of cells.

What is the structure of the cell (plasma) membrane?

Phospholipid bilayer with embedded proteins.

What is the primary function of mitochondria?

To produce ATP (energy currency).

What is the endomembrane system?

A series of interconnected membrane-bound organelles.

What is the role of the Golgi apparatus?

To modify, sort, and package proteins from the rough ER.

What is the function of lysosomes?

To break down and recycle unneeded cellular components.

What is the significance of the nuclear envelope?

It encloses the nucleus and is continuous with the endoplasmic reticulum.

What is the nucleolus?

A membrane-less structure inside the nucleus where ribosomes are assembled.

What is the function of the smooth endoplasmic reticulum?

Site of lipid synthesis and calcium storage.

What does the term 'karyotype' refer to?

The full set of an individual's chromosomes.

What did Schwann and Schleiden propose in the late 1830s?

They proposed that cells are the building blocks of all living things.

What is the difference between SEM and TEM?

SEM reveals outer 3D surface structure, while TEM shows internal cross-sections.

What are eukaryotic cells characterized by?

They have a membrane-bound nucleus and membrane-bound organelles.

What does the endomembrane system include?

It includes interconnected membrane-bound organelles such as the endoplasmic reticulum and Golgi apparatus.

What is the function of the rough ER?

It is the site of protein synthesis, studded with ribosomes.

What is the Golgi apparatus often referred to as?

The 'post office of the cell' for modifying, sorting, and packaging proteins.

What are the three types of cytoskeletal filaments?

Microfilaments, microtubules, and intermediate filaments.

What is the most abundant protein in the extracellular matrix?

Collagen.

What is the gel-like consistency of cytoplasm called?

Cytosol, which contains dissolved proteins, salts, and organelles.

What is a karyotype?

The full set of an individual's chromosomes.

What is the main idea of Virchow's theory?

Cells come from pre-existing cells.

List the four traits all cells share.

Membrane, DNA, cytoplasm, ribosomes.

What is the difference between a light microscope and an electron microscope?

Light microscopes use visible light, while electron microscopes (SEM and TEM) use electron beams for higher resolution.

What are the traits of eukaryotic cells?

Eukaryotic cells have a nucleus, membrane-bound organelles, and linear chromosomes.

Describe the structure of the phospholipid bilayer.

Polar heads face outward, non-polar tails face inward; it is semi-permeable.

What are the main components of the nucleus?

Nuclear envelope, pores, nucleolus (for ribosome assembly), and chromatin.

What is the role of mitochondria?

Mitochondria produce ATP, have their own DNA and ribosomes, and support the endosymbiotic theory.

Differentiate between Rough ER and Smooth ER.

Rough ER is involved in protein synthesis, while Smooth ER is involved in lipid synthesis and calcium storage.

Compare peroxisomes and lysosomes.

Peroxisomes break down fatty acids and detoxify, while lysosomes recycle materials and perform autophagy.

What are the three types of cytoskeleton components?

Microfilaments (actin), microtubules (tubulin, centrosome), and intermediate filaments.

What is the difference between cilia and flagella?

Cilia are short and numerous, while flagella are longer and fewer in number.

What is the extracellular matrix?

The extracellular matrix provides strength and facilitates cell communication; collagen is a key component.

Who is known as the 'Father of Genetics'?

Gregor Mendel.

What are the three principles of Darwin's theory of evolution by natural selection?

1. Characteristics are inherited. 2. Resources are limited, leading to competition. 3. Offspring vary, and some variation is inherited.

What is the Chromosomal Theory of Inheritance?

It states that genes are located on chromosomes and that meiosis is the basis for trait inheritance.

What significant contribution did Rosalind Franklin make to genetics?

She provided key X-ray data that helped determine the structure of DNA.

What is the Central Dogma of Molecular Biology?

It describes the two-step process of transcription (DNA to RNA) and translation (RNA to protein).

What was the Human Genome Project?

A project aimed at mapping the entire human genome, starting in the 1990s and completed in 2022.

What is CRISPR?

A gene-editing tool based on bacterial immune systems that allows for precise genetic modifications.