Cell Theory and Organelles Overview

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Questions and Answers

What does the term 'biology' specifically refer to?

Study of living organisms (correct)

Study of human anatomy

Study of cell functions

Study of ecosystems

Which of the following statements is included in the Modern Cell Theory?

All organisms are composed of multiple cells.

All cells have the ability to photosynthesize.

Only human cells share genetic material.

Energy flow occurs within cells through photosynthesis and mitochondria. (correct)

What does the phrase 'Omnis cellula e cellula' imply in the context of cell theory?

Cells can arise from non-cellular materials.

Every cell comes from a parent cell. (correct)

All cells contain identical DNA.

Cell division occurs only during reproduction.

What is a key feature of viruses according to cell theory?

They are just proteins and not living things. Signup and view all the answers

Which statement correctly summarizes a tenet of the Classic Cell Theory?

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

How does genetic information pass according to the Modern Cell Theory?

Through DNA or RNA during cell division. Signup and view all the answers

What percentage of genetic similarity exists between a human and another human?

99.99% Signup and view all the answers

Which historical figure is known for the discovery of cells?

Robert Hooke Signup and view all the answers

What is the main function of the nucleolus?

Ribosome production Signup and view all the answers

Which type of RNA is involved in specifying the sequence of amino acids in proteins?

Messenger RNA (mRNA) Signup and view all the answers

What structure separates the nucleoplasm from the cytoplasm?

Nuclear envelope Signup and view all the answers

How do ribosomes contribute to protein synthesis?

They assemble amino acids into proteins. Signup and view all the answers

What components make up the two subunits of a ribosome?

Ribosomal RNA and proteins Signup and view all the answers

Which of the following correctly describes the cytoplasm?

It consists of organelles and the cytosol. Signup and view all the answers

What type of cells can be multinucleated?

Skeletal muscle cells Signup and view all the answers

What is the role of nuclear pores in the nucleus?

They regulate the movement of substances in and out. Signup and view all the answers

What structure of the endoplasmic reticulum is responsible for storing powerful digestive enzymes?

Membranous sac Signup and view all the answers

What is a primary function of the smooth endoplasmic reticulum?

Synthesis of lipids Signup and view all the answers

Which function is NOT associated with the rough endoplasmic reticulum?

Detoxification of drugs Signup and view all the answers

What are the two faces of the Golgi apparatus referred to?

CIS and TRANS Signup and view all the answers

Which of the following best describes phagocytosis?

Digestion of food by lysosomes Signup and view all the answers

Which of the following represents a function of lysosomes?

Recycling of damaged organelles Signup and view all the answers

What is the main structural characteristic of the Golgi apparatus?

Stacks of flattened membranous sacs Signup and view all the answers

Which component of the endomembrane system is primarily involved in the synthesis of polysaccharides?

Golgi apparatus Signup and view all the answers

What is the primary function of a vacuole in plant cells?

Providing added support Signup and view all the answers

What is produced as a byproduct of the oxidation process in peroxisomes?

Hydrogen peroxide Signup and view all the answers

Which type of plastid is responsible for the green color in plants?

Chloroplasts Signup and view all the answers

What is the structure of peroxisomes primarily characterized by?

A single membrane Signup and view all the answers

Which compounds do leucoplasts primarily synthesize and store?

Starch and oils Signup and view all the answers

What role do thylakoids play in plastids?

Light-dependent reactions Signup and view all the answers

Which of the following is NOT a type of plastid?

Riboplast Signup and view all the answers

What is a key function of chloroplasts in plant cells?

Photosynthesis to produce sugars Signup and view all the answers

What is the primary function of the mitochondrion?

Cellular respiration Signup and view all the answers

Which component of the cytoskeleton is primarily responsible for maintaining cell shape and resisting compression?

Microtubules Signup and view all the answers

Which structure acts as a selective barrier in the cell?

Plasma membrane Signup and view all the answers

What type of cytoskeleton component is made up of actin proteins?

Microfilaments Signup and view all the answers

Which part of the mitochondrion contains enzymes and mitochondrial DNA?

Mitochondrial matrix Signup and view all the answers

Which type of cytoskeletal structure is involved in the movement of cilia and flagella?

Microtubules Signup and view all the answers

How do prokaryotes and eukaryotes primarily differ?

Presence of a nucleus Signup and view all the answers

What role do intermediate filaments play in the cell?

Anchoring organelles Signup and view all the answers

Study Notes

Cell Theory and Cell Organelles

Biology, derived from "Bio" (life) and "Logy" (knowledge), is fundamentally the study of life.
Cell Theory is a foundational theory in biology outlining the properties of cells.
Robert Hooke's discovery of cells prompted the establishment of classic Cell Theory by Theodor Schwann, Matthias Schleiden, and Rudolf Virchow.

Classic and Modern Cell Theory

Classic Cell Theory posits:
- All organisms are composed of cells.
- Cells function as the basic units of life.
- All cells arise from preexisting cells ("Omnis cellula e cellula").
Modern Cell Theory adds:
- Genetic information is transmitted via DNA or RNA.
- Cells across similar species share structural and chemical similarities.
- Energy flow within cells occurs through processes like photosynthesis.

Cellular Organelles Overview

Organelles are membrane-bound structures within cells, suspended in cytosol—the gel-like liquid inside the cell.

Nucleus

Serves as the information hub of the cell, housing chromosomes and nucleoli.
Contains nuclear pores that regulate entry and exit.
The nuclear envelope is continuous with the endoplasmic reticulum (ER).

Types of RNA

Messenger RNA (mRNA): Encodes amino acid sequences in proteins.
Ribosomal RNA (rRNA): Combines with proteins to form ribosomal subunits.
Transfer RNA (tRNA): Aids in assembling amino acids during protein synthesis.

Ribosomes

Act as protein factories, found free in cytosol or attached to the rough ER.
Composed of two subunits formed from rRNA and proteins.

Endoplasmic Reticulum (ER)

Smooth ER: Synthesis of lipids, carbohydrate metabolism, detoxification of drugs.
Rough ER: Contains ribosomes for protein synthesis and modification, also involved in membrane production.

Golgi Apparatus

Structured as stacks of flattened membranous sacs with distinct CIS and TRANS faces.
Modifies proteins and synthesizes polysaccharides and phospholipids for cellular transport.

Lysosomes

Membranous sacs filled with hydrolytic enzymes for digestion of cellular debris and macromolecules.
Function in phagocytosis (digesting food) and autophagy (breaking down damaged organelles).

Vacuoles

Large membrane-bound structures in plant cells, maintaining cell turgor pressure and storing nutrients.
Helps in cell growth and waste disposal.

Peroxisomes

Contain oxidation enzymes that transfer hydrogen atoms to oxygen, producing hydrogen peroxide.

Plastids

Capture light energy and are vital for photosynthesis; contain chlorophyll.
Types include chloroplasts (green), chromoplasts (pigments), and leucoplasts (store starch and oils).

Mitochondria

Known as the powerhouse of the cell; involved in cellular respiration.
Enclosed by double membranes, with an inner matrix that contains enzymes and mitochondrial DNA.

Plasma Membrane

Composed of a phospholipid bilayer with embedded proteins; serves as a selective barrier for substances entering and exiting the cell.

Cytoskeleton

Provides structural support, maintain cell integrity, facilitates motility, and aids in cell division.
Types include:
- Microtubules: Maintain shape and structure; involved in organelle positioning and cell division.
- Microfilaments: Composed of actin, essential for muscle movement and cellular division.
- Intermediate filaments: Provide tensile strength and help anchor organelles.

Prokaryotic vs. Eukaryotic Cells

Both cell types share DNA as genetic material and utilize ribosomes for protein synthesis.
Prokaryotes lack a nucleus and membrane-bound organelles, while eukaryotes possess a more complex structure, including a plasma membrane and potentially cell walls.

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Description

Explore the fundamental concepts of Cell Theory and the various organelles that make up cells in this quiz. Learn about the historical figures who contributed to Cell Theory and the key functions of different cellular components. Test your understanding of both classic and modern perspectives of cellular biology.