General Biology 1 - Cells Part 1 Quiz
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Questions and Answers

What characterizes an organic compound?

  • It must be derived from living organisms.
  • It cannot contain nitrogen.
  • It can exist only in gaseous form.
  • It must contain carbon as an element. (correct)

Which of the following gases was hypothesized to be part of Earth's early atmosphere?

  • Argon (Ar)
  • Carbon dioxide (CO2) (correct)
  • Oxygen (O2)
  • Nitrous oxide (N2O)

What was the relevance of the Miller-Urey experiment?

  • It showed that organic molecules are exclusively derived from meteorites.
  • It proved that life can form in the absence of organic compounds.
  • It demonstrated the importance of oxygen for the formation of life.
  • It simulated the early conditions of Earth to produce basic molecules for life. (correct)

Which molecule is considered inorganic despite containing carbon?

<p>Carbon dioxide (CO2) (C)</p> Signup and view all the answers

What percentage of the Tagish Lake meteorite's weight was found to be organic matter?

<p>3% (D)</p> Signup and view all the answers

Who was the first person to observe cells using a microscope?

<p>Robert Hooke (B)</p> Signup and view all the answers

What is the smallest unit of life according to cell theory?

<p>Cell (A)</p> Signup and view all the answers

Which factor does NOT affect the rate of diffusion in cells?

<p>Cell membrane thickness (A)</p> Signup and view all the answers

According to cell theory, how do cells arise?

<p>By division from a pre-existing cell (D)</p> Signup and view all the answers

What did Mathias Schleiden propose about plants?

<p>They are made of individual cells (D)</p> Signup and view all the answers

Why are organisms composed of many small cells advantageous?

<p>They increase surface area for diffusion (C)</p> Signup and view all the answers

What is a key limitation of larger cells compared to smaller cells?

<p>Volume increases more rapidly than surface area (A)</p> Signup and view all the answers

Who proposed the Cell Theory alongside Mathias Schleiden?

<p>Theodor Schwann (C)</p> Signup and view all the answers

What is one of the key properties common to all cells?

<p>Ability to replicate genetic material (A)</p> Signup and view all the answers

What role do amino acids play in the structure of living organisms?

<p>They are the building blocks of proteins. (B)</p> Signup and view all the answers

Which statement best describes the impact of surface-to-volume ratios on cell size?

<p>Smaller cells have a more efficient surface-to-volume ratio. (D)</p> Signup and view all the answers

How do prokaryotic cells differ from eukaryotic cells?

<p>Prokaryotic cells do not have membrane-bound organelles. (D)</p> Signup and view all the answers

Which of the following hypotheses suggests that life originated from extraterrestrial sources?

<p>Panspermia Hypothesis (A)</p> Signup and view all the answers

What is necessary for organic molecules to create life?

<p>They need to be assembled in a specific functional way. (C)</p> Signup and view all the answers

Which cellular structure is primarily responsible for energy production in eukaryotic cells?

<p>Mitochondria (A)</p> Signup and view all the answers

What analogy is used to describe the random assembly of organic molecules in the creation of life?

<p>Putting LEGO bricks in a washing machine. (C)</p> Signup and view all the answers

What aspect of cellular structures is primarily studied when comparing the cells of different organisms like bacteria, protists, and fungi?

<p>Structural characteristics (A)</p> Signup and view all the answers

How does the process of protein synthesis relate to amino acids?

<p>Ribosomes organize amino acids into proteins. (B)</p> Signup and view all the answers

Which of the following statements accurately represents the endosymbiotic theory?

<p>Eukaryotic organelles originated from independent bacteria. (D)</p> Signup and view all the answers

What aspect does the random event hypothesis highlight regarding the emergence of life?

<p>Life could occur from a random mishap over time. (C)</p> Signup and view all the answers

What is one theory about the origin of life mentioned?

<p>Life began in a primitive soup of organic molecules. (A)</p> Signup and view all the answers

What characteristic defines cells, according to the provided content?

<p>They are generally small and microscopic. (D)</p> Signup and view all the answers

Which of the following does NOT describe features that must have been present in the earliest cells?

<p>Ability to photosynthesize (A)</p> Signup and view all the answers

What is a necessary component for the building blocks of RNA and DNA?

<p>Nitrogenous bases (B)</p> Signup and view all the answers

What is the primary function of the plasma membrane?

<p>To separate the cell's contents from the surroundings (B)</p> Signup and view all the answers

Which component of the plasma membrane is responsible for its selective permeability?

<p>Phospholipids (B)</p> Signup and view all the answers

What does the nucleolus primarily produce?

<p>RNA for ribosomes (B)</p> Signup and view all the answers

What is the structure of the nuclear envelope?

<p>Two-layer phospholipid membrane (B)</p> Signup and view all the answers

In eukaryotic cells, DNA is organized into what structure?

<p>Linear chromosomes (C)</p> Signup and view all the answers

The cytoplasm of the cell can be analogously compared to what feature of a medieval city?

<p>The roads and pathways (C)</p> Signup and view all the answers

What role do proteins play within the plasma membrane?

<p>They act as receptors and channels for substances (B)</p> Signup and view all the answers

How does the plasma membrane transmit signals?

<p>Through receptor proteins that communicate with the external environment (A)</p> Signup and view all the answers

What is the primary function of ribosomes?

<p>Protein synthesis (D)</p> Signup and view all the answers

Which structure is responsible for the modification of proteins by adding carbohydrates?

<p>Rough Endoplasmic Reticulum (A)</p> Signup and view all the answers

What is the difference between rough and smooth endoplasmic reticulum?

<p>Rough ER contains ribosomes, whereas smooth ER does not. (D)</p> Signup and view all the answers

Where are ribosomes made?

<p>Nucleus (nucleolus) (C)</p> Signup and view all the answers

What role do nuclear pores play in cellular function?

<p>Facilitate diffusion of small molecules and ions (C)</p> Signup and view all the answers

How do ribosomes determine their association with the endoplasmic reticulum?

<p>Determined by the sequence of mRNA (D)</p> Signup and view all the answers

What is one of the main functions of the smooth endoplasmic reticulum?

<p>Assembly of membrane lipids (C)</p> Signup and view all the answers

What happens to proteins that are packaged into vesicles from the rough endoplasmic reticulum?

<p>They are modified in the Golgi apparatus (A)</p> Signup and view all the answers

What is the primary function of mitochondria in a cell?

<p>Produces energy in the form of ATP (C)</p> Signup and view all the answers

Which component of the cytoskeleton is responsible for maintaining cell shape and organizing organelles?

<p>Microtubules (D)</p> Signup and view all the answers

How are mitochondria inherited in humans?

<p>Only from the mother (D)</p> Signup and view all the answers

Which type of cytoskeletal fiber is considered the most durable?

<p>Intermediate filaments (D)</p> Signup and view all the answers

Cilia and flagella serve a similar function to which transportation system in a city?

<p>Airports (C)</p> Signup and view all the answers

What process converts nitrogen gas (N2) into a biologically accessible form for plants?

<p>Nitrogen fixation (C)</p> Signup and view all the answers

Which hypothesis suggests that RNA preceded DNA in the evolution of life?

<p>RNA world hypothesis (C)</p> Signup and view all the answers

What structural feature of prokaryotic cells helps protect them and maintain shape?

<p>Cell wall (D)</p> Signup and view all the answers

What is a defining characteristic of mitochondria as described by the endosymbiosis theory?

<p>They possess circular DNA. (A)</p> Signup and view all the answers

Which cellular structure acts as an enzyme and is made of RNA?

<p>Ribozyme (A)</p> Signup and view all the answers

What type of cellular structure increases the probability of metabolic reactions by separating internal and external environments?

<p>Plasma membrane (C)</p> Signup and view all the answers

Which organism classification is characterized by lacking a nucleus and membrane-bound organelles?

<p>Prokaryotes (B)</p> Signup and view all the answers

What is a common feature of chloroplasts as described by the endosymbiosis theory?

<p>Possess double membranes (B)</p> Signup and view all the answers

What primarily composes the cell wall of most bacteria?

<p>Peptidoglycan (A)</p> Signup and view all the answers

What major feature distinguishes archaea from bacteria?

<p>Complexity of cellular machinery for DNA replication (D)</p> Signup and view all the answers

What is the typical size range of prokaryotic cells?

<p>1 to 10 micrometers (C)</p> Signup and view all the answers

What is one of the components found in archaeal cell membranes that contributes to their stability?

<p>Saturated hydrocarbons (A)</p> Signup and view all the answers

Which structure is responsible for moving prokaryotic cells?

<p>Flagella (B)</p> Signup and view all the answers

Which of the following is a characteristic of eukaryotic cells?

<p>Presence of membrane-bound organelles (B)</p> Signup and view all the answers

What component is absent in the cell walls of archaea?

<p>Peptidoglycan (B)</p> Signup and view all the answers

Which mechanism provides energy for the rotation of prokaryotic flagella?

<p>Proton gradient (A)</p> Signup and view all the answers

What is the primary function of lysosomes in a cell?

<p>Digest and recycle old organelles (B)</p> Signup and view all the answers

Which statement correctly describes the structure of mitochondria?

<p>Rod-shaped with two phospholipid bilayer membranes (A)</p> Signup and view all the answers

What by-product is produced by peroxisomes during their oxidative processes?

<p>Hydrogen peroxide (B)</p> Signup and view all the answers

Which of the following roles does catalase play within peroxisomes?

<p>Decomposes hydrogen peroxide (D)</p> Signup and view all the answers

What role do cristae play in the function of mitochondria?

<p>Increase surface area for energy production (D)</p> Signup and view all the answers

What structure is characteristic of both cilia and flagella in eukaryotic cells?

<p>Circle of nine microtubule pairs surrounding two central microtubules (D)</p> Signup and view all the answers

Which of the following statements accurately describes the function of cilia?

<p>Cilia mostly assist in the movement of mucus in the respiratory system. (D)</p> Signup and view all the answers

What is the primary role of dynein in cilia and flagella?

<p>It facilitates the movement of microtubules past each other. (A)</p> Signup and view all the answers

How do flagella differ from cilia in terms of structure and quantity?

<p>Flagella are longer than cilia and are fewer in number. (C)</p> Signup and view all the answers

What essential function do centrioles perform during cell division?

<p>They help in moving chromosomes to the ends of the cell. (D)</p> Signup and view all the answers

Which of the following correctly describes the structure of chloroplasts?

<p>Chloroplasts contain two membranes and possess their own DNA. (B)</p> Signup and view all the answers

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

<p>Storage of sugars, ions, and waste products. (B)</p> Signup and view all the answers

What is the role of the tonoplast in relation to the central vacuole?

<p>It regulates the movement of water and maintains osmotic balance. (D)</p> Signup and view all the answers

What is the primary function of the Golgi Complex?

<p>Collection, packaging, and distribution of proteins and lipids (A)</p> Signup and view all the answers

Which best describes the structure of lysosomes?

<p>Small round vesicles that arise from the Golgi apparatus (C)</p> Signup and view all the answers

How do vesicles function in cellular transport?

<p>They can import and export materials into and out of the cell. (D)</p> Signup and view all the answers

What role does the cis face of the Golgi Complex serve?

<p>It receives materials from the endoplasmic reticulum. (A)</p> Signup and view all the answers

Which statement accurately describes glycoproteins?

<p>Proteins that have had carbohydrates added to them. (D)</p> Signup and view all the answers

What distinguishes prokaryotic cells from eukaryotic cells regarding organelles?

<p>Eukaryotic cells contain membrane-bound organelles. (D)</p> Signup and view all the answers

Which of the following processes facilitates the transport of materials into the cell?

<p>Endocytosis (B)</p> Signup and view all the answers

What is the function of the smooth endoplasmic reticulum?

<p>Synthesis of lipids and detoxification (B)</p> Signup and view all the answers

In what way does the Golgi Complex modify proteins?

<p>Through the addition of polysaccharides to them (A)</p> Signup and view all the answers

What is the primary component of vesicle structure?

<p>Bilayer of phospholipid (D)</p> Signup and view all the answers

Flashcards

Organic Compound

Any compound containing Carbon (C) as a key element. The formation of these compounds is essential, but not enough for life to exist.

Exception to Organic Compounds

Carbon dioxide (CO2) is the main exception. It contains carbon but is classified as inorganic.

Early Earth Atmosphere

The early Earth's atmosphere was rich in gases like carbon dioxide, nitrogen, water vapor, hydrogen, hydrogen sulfide, ammonia, and methane.

Miller-Urey Experiment

Stanley Miller and Harold Urey simulated the early Earth's atmosphere and oceans in a lab. They added energy through sparks and successfully produced complex organic molecules.

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Origins of Organic Molecules

The origin of organic molecules can be either extraterrestrial, like meteorites, or from Earth's own environment, as shown by the Miller-Urey experiment.

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Cell Theory

A fundamental concept in biology, stating that all living organisms are composed of cells and that all cells arise from pre-existing cells.

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Surface-to-Volume Ratio

The relationship between a cell's surface area and its volume. As a cell grows, its volume increases faster than its surface area.

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Prokaryotic Cell

A simple type of cell lacking a nucleus and membrane-bound organelles. Found in bacteria and archaea.

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Eukaryotic Cell

A complex type of cell with a nucleus and membrane-bound organelles. Found in plants, animals, fungi, and protists.

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Endosymbiotic Theory

The theory that explains the origin of mitochondria and chloroplasts in eukaryotic cells. These organelles were once free-living bacteria that were engulfed by larger cells.

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What are the key properties of life?

Properties of life include organization, metabolism, responsiveness, growth and development, reproduction, adaptation, and homeostasis.

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What are some features of the earliest cells?

Early cells likely lacked a nucleus, were simple in structure, and were capable of self-replication.

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Describe the 'primordial soup' hypothesis.

This hypothesis suggests that life originated in a warm, shallow pool of water containing organic molecules, which eventually self-assembled into the first cells.

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Nucleoid

A region in prokaryotic cells where the circular DNA is located.

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Plasma Membrane

A thin, flexible barrier that encloses a cell and controls what enters and exits.

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Lipid Bilayer

The structure of the plasma membrane, composed of two layers of phospholipids.

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Organelles

Specialized structures within cells that perform specific functions.

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Nucleus

The control center of a eukaryotic cell, containing the DNA.

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Nucleolus

A structure within the nucleus where ribosomes are made.

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Ribosomes

Organelles responsible for protein synthesis.

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DNA

The genetic material that carries instructions for building and maintaining an organism.

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Nuclear Pores

Channels in the nuclear envelope that allow small molecules and ions to pass freely, while regulating the movement of larger molecules like proteins and RNA-protein complexes.

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Ribosome Function

The ribosome is the site of protein synthesis. It acts as a 'builder', translating genetic information from mRNA into a chain of amino acids.

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Ribosomal Subunits

Each ribosome consists of two subunits, made of ribosomal RNA (rRNA) and proteins. These subunits work together to build proteins.

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Where are Ribosomes Made?

Ribosomes are assembled within the nucleus, specifically in the nucleolus.

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Ribosome Location

Ribosomes can be either attached to the endoplasmic reticulum (ER) or free in the cytosol.

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What does ER stand for?

Endoplasmic Reticulum.

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Rough ER Function

The rough ER is covered with ribosomes and is mainly involved in protein synthesis. It modifies proteins by adding carbohydrates to form glycoproteins.

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Smooth ER Function

The smooth ER lacks ribosomes and focuses on lipid and carbohydrate synthesis. It also stores calcium ions, important for cell signaling.

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Who discovered cells?

Robert Hooke, an English natural philosopher, was the first to observe cells in 1665. He named the shapes he saw in cork 'cellulae', which means 'small rooms' in Latin.

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What is the Cell Theory?

The Cell Theory states that all living things are made up of one or more cells, cells are the basic units of life, and new cells arise from pre-existing cells.

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Amino Acids

The building blocks of proteins, essential for creating the complex structures and functions needed for life.

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Nitrogenous Base

A component of DNA and RNA, carrying genetic information and playing a crucial role in the replication and expression of life's instructions.

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Why are most cells small?

Most cells are relatively small because they rely on diffusion to transport substances in and out. Diffusion is more efficient over short distances.

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What is the advantage of being made of many small cells?

Organisms made of many small cells have an advantage over organisms made of fewer, larger cells because they have a higher surface area to volume ratio, allowing for more efficient diffusion and transport.

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How do mismatched organic molecules form life?

The origin of life is a mystery, but the spontaneous assembly of organic molecules over vast periods might have led to the first self-replicating organisms.

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Surface Area to Volume Ratio

The surface area to volume ratio describes the relationship between the surface area of a cell and its volume. A higher ratio means more surface area relative to the volume, allowing for easier diffusion.

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Panspermia Hypothesis

The theory that life on Earth originated from extraterrestrial sources, possibly carried to our planet via meteorites or other celestial objects.

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What is diffusion?

Diffusion is the movement of molecules from an area of high concentration to an area of low concentration. It is a passive process that does not require energy.

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Extraterrestrial Origins

The idea that life may have begun outside of Earth and travelled to our planet, suggesting we could be related to beings from other planets.

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What are cells?

The fundamental building blocks of all living organisms, containing the machinery necessary for life's functions.

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What are the factors affecting diffusion rate?

The rate of diffusion is affected by several factors, including the surface area available, temperature, concentration gradient, and distance. A larger surface area, higher temperature, steeper gradient, and shorter distance all increase the rate of diffusion.

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How do cells overcome limitations of size?

Some cells, such as neurons, overcome the limitations of size by having a long and skinny shape, which increases their surface area to volume ratio and allows for efficient diffusion.

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Why can't we see cells?

Cells are incredibly small, often microscopic, requiring powerful tools like microscopes to be observed.

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What are ribosomes?

Cellular structures responsible for protein synthesis, translating the genetic code into functional proteins.

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Endomembrane System

A series of interconnected membranes within the cytoplasm of eukaryotic cells that divide the cell into compartments, allowing for specialized functions.

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Golgi Complex

A stack of flattened, membrane-bound sacs involved in modifying, sorting, and packaging proteins and lipids for secretion or delivery to other parts of the cell.

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Cis Face of Golgi

The receiving side of the Golgi complex, located near the endoplasmic reticulum (ER), where substances enter from the ER.

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Trans Face of Golgi

The exporting side of the Golgi complex, where modified and packaged substances exit in vesicles, ready for transport.

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Vesicle

Small membrane sacs, responsible for transporting substances within the cell and between the cell and its environment.

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Endocytosis

The process by which cells take in substances from their surroundings by enclosing them in a vesicle.

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Exocytosis

The process by which cells release substances from their interior to the outside, packaged within vesicles.

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Peroxisomes

Small, membrane-bound organelles that contain enzymes for breaking down fatty acids and detoxifying harmful substances.

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Glycoprotein

A protein with a sugar molecule (polysaccharide) attached to it, often involved in cell signaling and recognition.

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Mitochondria: Powerhouse of the Cell

Mitochondria are organelles responsible for generating ATP, the energy currency of the cell. They use oxygen and glucose to produce energy, releasing carbon dioxide and water as byproducts.

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Cytoskeleton: Cell's Framework

The cytoskeleton is a network of protein fibers that supports the cell's shape, keeps organelles in place, and facilitates movement. It's composed of three main types: Actin filaments, microtubules, and intermediate filaments.

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Actin Filaments

Actin filaments, also known as microfilaments, are thin, flexible protein fibers involved in cell shape, muscle contraction, and cell division.

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Lysosomes: What's their role?

Lysosomes are cell organelles that contain digestive enzymes. They break down old cell parts, recycle molecules, and destroy invading pathogens.

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Microtubules

Microtubules are hollow tubes made of tubulin protein. They provide structural support, facilitate organelle transport, and form the basis for cilia and flagella.

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Peroxisomes: What do they do?

Peroxisomes are small organelles that break down fatty acids and some amino acids. They produce hydrogen peroxide, which they break down safely using the enzyme catalase.

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Intermediate Filaments

Intermediate filaments are strong, rope-like structures that provide structural support and help anchor organelles. They are the most durable component of the cytoskeleton.

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Mitochondria: What is its role?

Mitochondria are the powerhouse of the cell, responsible for producing energy in the form of ATP through cellular respiration. They use glucose and oxygen to create energy.

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What is the Endoplasmic Reticulum?

The endoplasmic reticulum (ER) is a network of membranes within the cell. It comes in two forms: Rough ER and Smooth ER.

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Rough ER: What does it do?

The rough ER is covered in ribosomes. Its main function is protein synthesis and modification.

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Peptidoglycan

A complex sugar molecule found in bacterial cell walls, providing strength and protection.

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Archaea Cell Walls

Made of various compounds, including polysaccharides, proteins, and even inorganic components. They lack peptidoglycan.

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Rotating Flagella

Whip-like structures found on some prokaryotes, helping them move by rotating.

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Cilia and Flagella

Both are used for motion in eukaryotes. Cilia are shorter, more numerous, and found in various locations like the respiratory system. Flagella are longer, fewer, and are found in sperm cells.

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9 + 2 Structure

This refers to the arrangement of microtubules in cilia and flagella. Nine pairs of microtubules surround two central microtubules.

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Prokaryotic vs. Eukaryotic Size

Prokaryotic cells are much smaller than eukaryotic cells (1-10 micrometers vs. 10-100 micrometers).

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Membrane-Bound Nucleus

A defining characteristic of eukaryotic cells, containing the cell's DNA.

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Dynein Protein

A motor protein that helps microtubules slide past each other, providing the energy for cilia and flagella movement.

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Prokaryote vs. Eukaryote Flagella

Prokaryotes have rotating flagella powered by a proton gradient, while eukaryotes have different types of flagella.

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Centrioles

Small, cylindrical structures found in animal cells. Two centrioles are arranged perpendicularly to each other, forming a centrosome.

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Plant Cell - Central Vacuole

Large, fluid-filled sac in plant cells. It stores sugars, ions, pigments, and waste. Also involved in maintaining water balance.

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Plant Cell - Cell Wall

A rigid, protective outer layer of plant cells. It provides support and structure.

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Cytoskeleton

A network of protein fibers in eukaryotic cells, providing support, shape, and movement.

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Plant Cell - Chloroplasts

Organelles responsible for photosynthesis in plants. Contain chlorophyll to capture light energy.

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Tonoplast

The membrane surrounding the central vacuole in plant cells. Contains channels for water to maintain osmotic balance.

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Nitrogen Fixation

The process by which microbes convert unusable nitrogen gas (N2) from the atmosphere into biologically available ammonia (NH3) that plants can use.

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RNA World Hypothesis

The hypothesis that RNA, not DNA, was the primary form of genetic material in early life. RNA can store genetic information, catalyze reactions, and act as a structural molecule.

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Mitochondria Endosymbiosis

The theory that mitochondria, organelles responsible for energy production, were once free-living bacteria that were engulfed by larger cells.

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Chloroplast Endosymbiosis

The theory that chloroplasts, organelles responsible for photosynthesis, were once free-living bacteria that were engulfed by larger cells.

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Endosymbiosis

A process where one organism lives inside another, often with both organisms benefiting. This is how mitochondria and chloroplasts are believed to have originated in eukaryotic cells.

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Study Notes

General Biology 1 - Fall 2024 - The Cells Part 1 & 2

  • The course covers cells, focusing on part 1 and 2.
  • The textbook used is Raven, Biology, 13th edition, Chapter 4.
  • The material is organized around sections of the book and includes suggested study materials.

Cell Theory

  • All organisms are made of one or more cells.
  • Cells are the smallest living things and the basic unit of life.
  • Cells only arise from pre-existing cells.

Surface Area to Volume Ratio

  • Large cells have a smaller surface area-to-volume ratio compared to smaller cells.
  • This ratio affects the rate of diffusion in and out of the cell
  • Smaller surface area-to-volume limits cell size.
  • This is important for the ability of a cell to interact with the surrounding environment.

Prokaryotic vs. Eukaryotic Cells

  • Distinction between the two cell types needs to be understood. Prokaryotes (bacteria and archaea) lack a membrane-bound nucleus, while eukaryotes possess one.

Cell Structure

  • Cells have a membrane, and cytoplasm (the liquid portion within).
  • Organelles are specialized parts inside the cell. These include a range of structures as discussed in further detail.

Origins of Life

  • There are hypotheses about the origin of organic molecules on Earth.
  • One scenario is that life originated on Earth, in a dilute, hot, "smelly" soup of ammonia, formaldehyde, formic acid, cyanide, methane, hydrogen sulfide and organic hydrocarbons.
  • Another scenario for the origin of life is from extraterrestrial origins. Hundreds of thousands of meteorites and comets impacted early Earth.
  • Recent findings suggest at least some meteorites have carried organic materials—as demonstrated by the Tagish-Lake meteorite which contained 3% organic matter.
  • American chemists Stanley Miller and Harold Urey recreated the primitive oceans and atmospheric conditions in the lab to demonstrate the formation of amino acids from inorganic precursors.

Endosymbiotic Theory

  • This theory explains the origin of eukaryotic organelles.
  • It examines the evidence supporting the idea that mitochondria and chloroplasts were once independent prokaryotic organisms that were engulfed by larger cells. This is further explored in separate sections on mitochondrial and chloroplast endosymbiosis.

Golgi Complex

  • The Golgi complex is involved in modifying, sorting, tagging, and packaging proteins and lipids for secretion or use within the cell.
  • It has a structure with flattened, membrane-bound sacs called cisternae, and processing occurs at the cis and trans faces.
  • The Golgi modifies proteins and lipids by adding carbohydrate chains, producing glycoproteins and glycolipids.
  • Vesicles transport materials to and from the Golgi.

Vesicles

  • Vesicles are small membrane-bound sacs that transport materials within the cell.
  • Two types of transport are endocytosis (bringing materials into the cell) and exocytosis (exporting materials out of the cell).

Lysosomes and Peroxisomes

  • Lysosomes are vesicles containing enzymes that break down biomolecules. They function in intracellular digestion, recycling, and breakdown of old cell parts.
  • Peroxisomes are smaller organelles involved in the breakdown of fatty acids and producing hydrogen peroxide, a by-product that is further processed by the enzyme catalase.

Mitochondria

  • Mitochondria have a double membrane and cristae (folds in the inner membrane increasing surface area for ATP production).
  • They are responsible for cellular respiration, creating ATP (adenosine triphosphate) the energy currency of cells.

Cytoskeleton

  • The cytoskeleton is a network of protein fibers that provides support and structure to the cell.
  • The cytoskeleton is crucial for maintaining cell shape, controlling movement, and positioning organelles. It consists of three types of fibers: microfilaments (actin), microtubules, and intermediate filaments.

Cilia and Flagella

  • Cilia and flagella are cellular extensions that function in movement.
  • Cilia are shorter and more numerous than flagella. Flagella are longer and typically found in single instances per cell.
  • The 9+2 arrangement (nine pairs of microtubules surrounding two central microtubules) is characteristic of eukaryotic flagella and cilia.

Centrosome

  • The centrosome is an organelle that functions in cell division.
  • It is composed of two centrioles and associated proteins. The centrioles move chromosomes during cell division.

Plant Cells

  • Plant cells have distinct structures, including a central vacuole, cell wall, and chloroplasts.
  • Vacuoles store water, ions, and waste; the cell wall helps maintain plant shape and rigidity, while chloroplasts are involved in photosynthesis. These plant cell characteristics are different from animal cell features.

Chloroplasts

  • Chloroplasts are organelles found in plant cells and some other eukaryotes involved in photosynthesis.
  • They have a double membrane and contain their own DNA and ribosomes.

Landmarks in Metabolism

  • Oxygenic photosynthesis and the process of carbon fixation are pivotal in the early evolution of cellular metabolism.
  • Nitrogen fixation by microbes plays a crucial role in making nitrogen bioavailable for organisms. RNA is thought to predate DNA in terms of cellular functions.

Prokaryotes

  • Prokaryotic cells are simple, single-celled organisms that lack a nucleus and other membrane-bound organelles..
  • They include bacteria and archaea, and have a cell wall made of peptidoglycan in bacteria, but differ in specific composition in archaea.
  • Prokaryotic flagella rotate to provide movement.
  • Eukaryotic cells are more complex, characterized by their membrane-enclosed nucleus, other organelles and cytoskeleton. There are differences noted in the function and structure of many similar organelles across different cell types. Comparing cell types is critical in identifying their uniqueness.

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Description

This quiz covers Chapter 4 from Raven's Biology 13th edition, focusing on the fundamental concepts of cells. Explore cell theory, the surface area-to-volume ratio, and the distinction between prokaryotic and eukaryotic cells. Test your understanding of cell structure and functions in this comprehensive assessment.

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