Cell Biology Overview and Robert Hooke
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Questions and Answers

Archaea are known to live only in environments without extreme conditions.

False (B)

Name one example of a methanogen.

Methanobrevibacter smithii

The domain that includes animals, plants, fungi, and protozoa is called __________.

Eukarya

Match the domains with their characteristics:

<p>Bacteria = Single-celled, non-nucleated organisms Archaea = Extremophiles with diverse metabolic strategies Eukarya = Includes animals, plants, fungi, and protozoa</p> Signup and view all the answers

What term did Robert Hooke coin while discussing the structure of cork?

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

Antonie van Leeuwenhoek was primarily interested in studying plant anatomy.

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

In what year did Robert Hooke publish his important work, Micrographia?

<p>1665</p> Signup and view all the answers

Antonie van Leeuwenhoek is known as the father of __________.

<p>microbiology</p> Signup and view all the answers

Match the scientists with their contributions to cell biology:

<p>Robert Hooke = Coined the term 'cell' Antonie van Leeuwenhoek = First to observe bacteria Both = Pioneered microscopy Neither = Studied chemical composition of cells</p> Signup and view all the answers

Which of the following was NOT a type of specimen observed by Robert Hooke?

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

Robert Hooke and Antonie van Leeuwenhoek were contemporaries.

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

What was Antonie van Leeuwenhoek's primary instrument for his observations?

<p>Microscope</p> Signup and view all the answers

Who first stated the cell theory?

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

All living organisms consist of multiple cells according to the cell theory.

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

What does the phrase 'omnis cellula e cellula' mean?

<p>Every cell arises from another cell.</p> Signup and view all the answers

The three tenets of the cell theory are: 1) All living organisms are composed of one or more cells, 2) The cell is the basic unit of structure and organization in organisms, and 3) Cells arise from __________.

<p>pre-existing cells</p> Signup and view all the answers

Which of the following contains a nucleus?

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

Match the following scientists with their contributions to cell theory:

<p>Matthias Schleiden = First to appreciate importance of cells Theodor Schwann = Extended cell theory to animals Rudolf Virchow = Proposed 'omnis cellula e cellula' Robert Hooke = Examined dead tissues in cork</p> Signup and view all the answers

Virchow made a significant contribution to cell theory by claiming that all cell tissues originate from a fluid called blastema.

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

The three domains of life include Bacteria, Archaea, and __________.

<p>Eukarya</p> Signup and view all the answers

Which of the following best describes prokaryotic cells?

<p>They lack a true nucleus. (A)</p> Signup and view all the answers

Which type of organism is classified under the Domain Archaea?

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

In which Domain would you classify a typical mushroom?

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

What is a common characteristic of eukaryotic cells compared to prokaryotic cells?

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

Which of the following statements is true regarding organisms in Domain Bacteria?

<p>They are typically non-nucleated single-celled organisms. (B)</p> Signup and view all the answers

What does cell biology primarily study?

<p>The structure, function, and behavior of cells (A)</p> Signup and view all the answers

Who is credited with coining the term 'cell'?

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

What significant observation did Antonie van Leeuwenhoek make in 1676?

<p>He observed tiny organisms in water (A)</p> Signup and view all the answers

What was one of the important discoveries made by van Leeuwenhoek related to reproduction?

<p>Observing spermatozoa and their role in fertilization (C)</p> Signup and view all the answers

What type of organisms can cell biology encompass?

<p>Both prokaryotic and eukaryotic organisms (A)</p> Signup and view all the answers

What is one aspect cell biology does NOT study?

<p>Evolution of species (A)</p> Signup and view all the answers

In what field did Robert Hooke conduct significant research?

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

How did Antonie van Leeuwenhoek first encounter magnifying glasses?

<p>Through his work in a textile shop (D)</p> Signup and view all the answers

What important concept did Matthias Schleiden contribute to biology?

<p>All organisms consist of one or more cells. (C)</p> Signup and view all the answers

Which statement best describes Rudolf Virchow's contribution to cell theory?

<p>He stated that cells arise from pre-existing cells. (A)</p> Signup and view all the answers

What was the major flaw in Virchow's earlier explanation for cell reproduction?

<p>He claimed new cells were formed from blastema. (B)</p> Signup and view all the answers

How did Theodor Schwann contribute to cell theory?

<p>He extended the cell theory to animals. (C)</p> Signup and view all the answers

Which of the following is NOT one of the three tenets of cell theory?

<p>All living organisms possess specialized organs. (B)</p> Signup and view all the answers

What defines prokaryotic cells compared to eukaryotic cells?

<p>Prokaryotic cells lack a defined nucleus. (D)</p> Signup and view all the answers

How did Hooke's observations differ from those of Schleiden?

<p>Hooke viewed dead cells, focusing on shapes, while Schleiden observed living cells in motion. (D)</p> Signup and view all the answers

What are the three domains of life as classified in the modern biological hierarchy?

<p>Bacteria, Archaea, Eukarya (A)</p> Signup and view all the answers

What effect do increased levels of unsaturated hydrocarbon chains have on membrane fluidity?

<p>Increase membrane fluidity (B)</p> Signup and view all the answers

Which of the following is NOT a major function of membrane proteins?

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

Lipid rafts are important for which of the following functions?

<p>Facilitating cell communication and signaling (D)</p> Signup and view all the answers

What type of movement between phospholipids in the bilayer is most commonly observed?

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

How does cholesterol affect the fluidity of cell membranes at physiological temperatures?

<p>Decreases fluidity by stiffening the membrane (A)</p> Signup and view all the answers

Which class of membrane proteins is primarily involved in catalyzing biochemical reactions?

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

What common characteristic do flippase, floppase, and scramblase share?

<p>They facilitate the movement of lipids across the bilayer (C)</p> Signup and view all the answers

Which factor does NOT influence the fluidity of the membrane?

<p>Presence of carbohydrates (C)</p> Signup and view all the answers

What is the primary role of the cell cortex in cellular functions?

<p>Cell shape maintenance (B)</p> Signup and view all the answers

Which structure is primarily responsible for maintaining the shape of red blood cells?

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

What is one of the main functions of the glycocalyx on the extracellular side of the plasma membrane?

<p>Facilitating cell cell recognition (A)</p> Signup and view all the answers

What effect does the binding of lipid molecules have on membrane proteins?

<p>Stabilizes the protein structure (D)</p> Signup and view all the answers

How would a mutation in the spectrin protein affect red blood cells?

<p>Cause them to lose their shape (A)</p> Signup and view all the answers

Which of the following accurately describes the fluidity of cell membranes?

<p>Membranes have a fluid lipid bilayer that allows proteins to move within it. (A)</p> Signup and view all the answers

What is one primary function of membrane proteins?

<p>They facilitate communication and signaling between cells. (D)</p> Signup and view all the answers

Which type of membrane protein extends across the bilayer and may function as channels or transporters?

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

What is an example of a mechanism for transporting substances across membranes?

<p>Active transport using ATP energy (D)</p> Signup and view all the answers

Which component is NOT a major class of membrane lipids?

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

What are lipid rafts primarily composed of?

<p>Higher concentrations of cholesterol and glycosphingolipids (C)</p> Signup and view all the answers

How do amphipathic molecules behave in a bilayer structure?

<p>They align their hydrophobic regions inward and hydrophilic regions outward. (B)</p> Signup and view all the answers

Which type of phospholipid is characterized by a polar head group containing phosphoserine?

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

What is the primary function of the cell cortex?

<p>To determine cell shape and support (A)</p> Signup and view all the answers

What effect does a mutation in spectrin have on red blood cells?

<p>Formation of abnormally shaped red blood cells (C)</p> Signup and view all the answers

Which components make up the glycocalyx found on the extracellular side of the plasma membrane?

<p>Glycolipids, glycoproteins, and proteoglycans (D)</p> Signup and view all the answers

What role does the glycocalyx play in the immune system?

<p>It helps immune cells adhere to pathogens (B)</p> Signup and view all the answers

Lipid-anchored membrane proteins are characterized by what feature?

<p>Covalently binding to lipid molecules in the membrane (C)</p> Signup and view all the answers

Which type of integral membrane protein contains no transmembrane domains?

<p>Integral monotopic proteins (A)</p> Signup and view all the answers

What is a characteristic feature of multipass proteins?

<p>They can form pores for transporting polar molecules. (D)</p> Signup and view all the answers

What type of amino acids are typically found in regions outside of the membrane for integral membrane proteins?

<p>Hydrophilic amino acids (A)</p> Signup and view all the answers

What method is commonly used for isolating membrane-bound proteins?

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

Which of the following best describes the bonding of peripheral membrane proteins to membrane surfaces?

<p>They associate through weak electrostatic forces. (D)</p> Signup and view all the answers

Which class of integral membrane proteins can consist of multiple distinct polypeptides?

<p>Multi-subunit integral proteins (B)</p> Signup and view all the answers

Which amino acid composition is typical in alpha helices found in multipass proteins?

<p>Mostly hydrophobic amino acids (B)</p> Signup and view all the answers

What is the critical micelle concentration (CMC) related to in the context of detergents?

<p>The point at which detergents can effectively solubilize proteins. (C)</p> Signup and view all the answers

What primarily contributes to the fluidity of the cell membrane?

<p>Number of double bonds in hydrocarbon tails of phospholipids (D)</p> Signup and view all the answers

What is the primary purpose of membranes in cell biology?

<p>To serve as a physical barrier while mediating molecule transport and communication (D)</p> Signup and view all the answers

Which type of membrane protein serves to anchor the plasma membrane to the cytoskeleton?

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

Which of the following correctly describes the fluid mosaic model of cell membranes?

<p>Proteins float within a fluid lipid bilayer allowing movement (C)</p> Signup and view all the answers

Which class of lipids is NOT a major component of cell membranes?

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

What is a characteristic function of lipid rafts in cell membranes?

<p>Concentrating specific lipids and proteins for signal transduction (D)</p> Signup and view all the answers

How do flippase, floppase, and scramblase contribute to membrane dynamics?

<p>By promoting the movement of lipids between monolayers (A)</p> Signup and view all the answers

What is the role of phospholipids in membrane structure?

<p>They create a bilayer with hydrophilic heads and hydrophobic tails (A)</p> Signup and view all the answers

What happens to membrane fluidity when the length of phospholipid hydrocarbon chains increases?

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

Which type of lipid is characterized by having two hydrocarbon chains and a polar head group?

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

What characteristic does NOT pertain to cell membranes?

<p>Cell membranes are rigid structures (B)</p> Signup and view all the answers

Which statement about phospholipid movement in the membrane is accurate?

<p>Phospholipids rotate and laterally diffuse within the bilayer. (B)</p> Signup and view all the answers

How does the presence of cholesterol affect the fluidity of cell membranes at physiological temperatures?

<p>It maintains fluidity by resisting changes in temperature. (B)</p> Signup and view all the answers

Which of the following statements about membrane proteins is incorrect?

<p>Membrane proteins are entirely hydrophobic. (C)</p> Signup and view all the answers

In which of the following membrane functions are receptor proteins primarily involved?

<p>Receiving signals and communication (A)</p> Signup and view all the answers

How does cholesterol influence the fluidity of cell membranes?

<p>It maintains membrane fluidity at physiological temperatures (A)</p> Signup and view all the answers

Flashcards

Prokaryotic Cells

Single-celled organisms lacking a nucleus and membrane-bound organelles.

Eukaryotic Cells

Cells containing a nucleus and membrane-bound organelles.

Domains of Life (Biology)

Highest taxonomic rank, classifying organisms into Bacteria, Archaea, and Eukarya.

Typical Eukaryotic Cell Characteristics

Generally larger than prokaryotes, can be unicellular or multicellular, maximize surface area to volume ratio, contain a nucleus and membrane bound organelles.

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Major Membrane-bound Organelles

Cellular structures with specific functions within eukaryotic cells, crucial for cell function.

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Cell Theory

All living things are made of cells, cells are the basic units of structure and organization in organisms, and new cells arise from pre-existing cells.

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Schleiden

Scientist who first emphasized the importance of cells in plants, contributing to the cell theory.

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Schwann

Scientist who expanded the cell theory to animals (in 1839).

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Virchow

Scientist who corrected Schwann's incorrect ideas about cell reproduction with his famous 'omnis cellula e cellula' (every cell from another cell).

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Prokaryotes

Cells that do not have a nucleus. They are the most diverse and numerous cells on earth.

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Eukaryotes

Cells that contain a nucleus.

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Bacteria

A type of prokaryotic cell.

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Archaea

Another type of prokaryotic cell.

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Cell Biology Definition

Cell biology is the study of cells, their structure, function, and behavior.

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Robert Hooke's Contribution

Hooke coined the term "cell" while studying cork under a microscope.

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Antonie van Leeuwenhoek's Role

Leeuwenhoek was a pioneer in microbiology, observing tiny living organisms and discovering bacteria.

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Cell as Basic Unit

Cells are the fundamental building blocks of all living organisms.

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Micrographia's Importance

Micrographia was a groundbreaking book that documented microscopic observations.

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Microscopes' use in cell biology

Microscopes are essential instruments for studying cells.

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What are the three domains of life?

The three domains of life are Bacteria, Archaea, and Eukarya. This classification system represents the highest level of biological organization.

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What are some common examples of Bacteria?

Examples of Bacteria include Escherichia coli, Streptococcus sp., Salmonella sp., and Bacillus sp. These organisms are often single-celled and lack a nucleus.

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What makes Archaea unique?

Archaea are prokaryotes that often thrive in extreme environments with diverse metabolic strategies. They don't have a nucleus.

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What are some examples of Eukarya?

Eukarya encompasses a wide range of organisms including animals, plants, fungi, protozoa, and algae. These organisms are characterized by having a nucleus and other membrane-bound organelles.

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Why is SA:VOL important for cells?

Surface area to volume ratio (SA:VOL) is important for cells because it affects their ability to exchange materials with their surroundings. Larger cells have a smaller SA:VOL ratio, making it harder for them to efficiently move nutrients in and waste out.

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What does 'cytology' mean?

Cytology is another name for cell biology, derived from the Greek word 'kytos', meaning 'vessel' or 'container,' referring to the cell as the basic unit of life.

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What is the focus of cell biology?

Cell biology investigates the structure, function, and behavior of cells, the fundamental building blocks of all living organisms.

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Who coined the term 'cell'?

Robert Hooke, a renowned polymath of the 17th century, first used the term 'cell' to describe the structure of cork while observing it under a microscope.

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What did Antonie van Leeuwenhoek discover?

Van Leeuwenhoek, a Dutch scientist, is credited with the first observation of bacteria, tiny living organisms invisible to the naked eye.

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Micrographia

Micrographia was a groundbreaking book published in 1665 by Robert Hooke showcasing his observations and discoveries using a microscope.

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Microscopy and cell biology

Microscopes are essential tools in cell biology, allowing scientists to visualize and study the intricate structures and processes within cells.

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Who first studied living cells?

Matthias Schleiden, a German botanist, studied living plant cells and observed their internal movement.

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Schleiden's contribution to the Cell Theory

Schleiden proposed that all living organisms are composed of cells, forming the basis of the Cell Theory.

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Schwann's extension of the Cell Theory

Theodor Schwann, a German physiologist, extended Schleiden's ideas about the Cell Theory to include animals.

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Cell division: 'omnis cellula e cellula'

Rudolf Virchow, a German pathologist, established that all cells arise from pre-existing cells, a fundamental principle of cell reproduction.

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What are the three tenets of the Cell Theory?

  1. All living organisms are composed of one or more cells. 2. The cell is the basic unit of structure and organization in organisms. 3. Cells arise from pre-existing cells.
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Prokaryotes: No nucleus

Prokaryotes are single-celled organisms that lack a nucleus and other membrane-bound organelles. They are the most diverse and numerous life forms on Earth.

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Eukaryotes: With a nucleus

Eukaryotes have a nucleus and other membrane-bound organelles, they can be single-celled or multicellular.

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Lipid Bilayer Asymmetry

The two layers of the lipid bilayer have different compositions, including phospholipid types, cholesterol amounts, protein distribution, and glycolipids predominantly on the extracellular side.

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Sea of Lipids

This term describes the fluidity of the cell membrane, where phospholipids and proteins can move laterally within the bilayer.

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Phospholipid Movement

Phospholipids can rotate around their axis and move laterally within the bilayer. Flipping from one layer to the other is rare.

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FRAP

Fluorescence Recovery After Photobleaching is a technique used to measure the lateral diffusion of membrane components.

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Fluidity Influencers

The fluidity of the membrane depends on the number of double bonds in phospholipid tails, the length of those tails, and the amount of cholesterol present.

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Unsaturated Tails Increase Fluidity

Double bonds in unsaturated fatty acid tails create kinks, increasing the fluidity of the membrane.

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Cholesterol and Fluidity

Cholesterol, a rigid molecule, stiffen the membrane at physiological temperatures, reducing its fluidity.

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Lipid Rafts

These are specialized areas on the membrane with high concentrations of glycosphingolipids, cholesterol, and specific proteins. They are important for cell signaling and function.

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What makes up cell membranes?

Cell membranes are composed of a phospholipid bilayer, where the phospholipids have polar heads and non-polar tails, creating a barrier between the cell and its external environment. This bilayer is embedded with various proteins.

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Fluid Mosaic Model

This model describes the structure of the cell membrane: a fluid phospholipid bilayer with embedded proteins, which move around freely.

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Phospholipid Structure

Phospholipids are composed of two parts: a polar head group (hydrophilic) attached to a non-polar tail (hydrophobic) consisting of fatty acid chains.

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Types of Phospholipids

Major types of phospholipids include phosphatidylcholine, phosphatidylserine, and phosphatidylinositol. They all have a polar head group but differ in the chemical composition of their head.

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Bilayer Formation

Phospholipids spontaneously form bilayer structures in aqueous environments. The polar heads face the water, while the non-polar tails face inward, creating a hydrophobic barrier.

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Amphipathic

Molecules like phospholipids are amphipathic, meaning they have both hydrophilic and hydrophobic regions. This property is crucial for forming membranes.

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Membrane Variation

Different cell membranes have different compositions of phospholipids, depending on their specific functions and environmental conditions.

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Triacylglycerol vs. Phospholipid

Triacylglycerols (fats) are different from phospholipids. They have three nonpolar tails and no polar head group.

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Lipid-Anchored Proteins

Proteins located on the membrane surface that are covalently attached to lipid molecules embedded within the cell membrane.

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Cell Cortex

A network of actin proteins beneath the plasma membrane that provides support and helps determine cell shape.

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Spectrin

The primary protein found in the cell cortex of red blood cells, providing support and maintaining cell shape.

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Glycocalyx

A sugar-rich layer on the extracellular side of the plasma membrane composed of glycoproteins, glycolipids, and proteoglycans.

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Functions of Glycocalyx

The glycocalyx is involved in cell-cell recognition, immune system recognition, cell adhesion, protecting against chemical injury, and providing a slimy coating on the outer cell surface.

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Membrane Function

Cell membranes act as physical barriers, control molecule movement in and out, participate in communication through signals and receptors, and enable cell adhesion.

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Lipid-Anchored Membrane Proteins

These proteins are attached to the cell membrane via a covalent bond to lipid molecules which are embedded in the membrane.

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What are the three major classes of membrane lipids?

The three major classes of membrane lipids are cholesterol, glycolipids, and phospholipids.

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What happens to phospholipids in an aqueous environment?

Phospholipids spontaneously form bilayers in an aqueous environment, with polar heads facing the water and non-polar tails facing inward.

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What are the functions of the Glycocalyx?

This layer helps with cell-cell recognition, immune system recognition, cell adhesion, protecting against chemical injury, and creating a slimy outer coating on the cell.

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Membrane Lipid Variation

All cell membranes do not have the same phospholipid composition, with different ratios reflecting their specific functions and environmental conditions.

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Membrane Asymmetry

The two layers of the lipid bilayer have different compositions. For example, glycolipids are more frequent on the extracellular side.

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Double Bonds and Fluidity

Unsaturated fatty acid tails (with double bonds) create kinks, increasing the fluidity of the membrane.

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Membrane Protein Functions

Membrane proteins play four major roles: transport, anchoring, reception, and enzymatic activity.

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Integral Membrane Proteins

Proteins embedded within the lipid bilayer of a cell membrane. Some regions are embedded in the membrane, while others extend outside. These proteins are essential for various cellular functions.

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Transmembrane Domains

Regions of an integral membrane protein that span the entire lipid bilayer. These domains are typically composed of hydrophobic amino acids, allowing them to interact with the nonpolar interior of the membrane.

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Types of Integral Membrane Proteins

Integral membrane proteins can be classified into different types based on their structure and association with the membrane. These types include: integral monotopic, singlepass, multipass, and multisubunit proteins.

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Integral Monotopic Proteins

Proteins embedded in only one leaflet (layer) of the lipid bilayer. They do not have transmembrane domains, so they have one region inside and one region outside the membrane. They serve as membrane-bound enzymes.

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Singlepass Proteins

Proteins containing one transmembrane domain. They are typically alpha helices and are involved in various functions, including acting as receptors and anchors.

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Multipass Proteins

Proteins containing multiple transmembrane domains. These domains can be alpha helices or beta sheets and, when arranged as alpha helices, can form channels through the membrane for transporting polar molecules.

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Multisubunit Integral Proteins

Proteins formed by multiple polypeptide chains, each with transmembrane domains that interact with each other within the membrane. These proteins are crucial for membrane-bound enzymes and receptors.

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Detergents and Membrane Proteins

Detergents are chemical compounds used to isolate and solubilize membrane-bound proteins. They disrupt the lipid bilayer, allowing proteins to be extracted from the membrane.

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Study Notes

Cell Biology Overview

  • Cell biology, also known as cytology, is a branch of biology focusing on the structure, function, and behavior of cells, the basic unit of life.
  • It examines cell properties, metabolic activities, signaling pathways, the cell cycle, chemical composition, and interactions with the environment.
  • Analysis occurs at both microscopic and molecular levels, encompassing both prokaryotic and eukaryotic cells.

Robert Hooke

  • Robert Hooke, a 17th-century English scientist, is considered a "Renaissance Man" for his contributions across various scientific fields, including astronomy, physics, and biology.
  • His significant publication, Micrographia (1665), documents microscopic observations.
  • Hooke coined the term "cell" while studying the structure of cork.
  • Hooke also accurately identified fossils as remnants of once-living organisms.
  • He detailed observations of various objects, including insects, feathers, and snowflakes, using a microscope.

Antonie van Leeuwenhoek

  • Antonie van Leeuwenhoek was a 17th-century Dutch textile merchant who later became a pioneering microscopist.
  • He constructed over 500 microscopes and used them for observations, leading to the discovery of microorganisms.
  • In 1676, van Leeuwenhoek described tiny organisms (bacteria) in water, marking a significant step in microbiology.
  • His study of sperm and the fertilization process introduced the novel idea of sperm penetrating the egg at fertilization.

Cell Theory Development

  • Matthias Schleiden, a botanist, recognized the fundamental role of cells in living organisms. His work, Contributions to Phytogenesis (1838), established the importance of cells in plant life, proposing all plants are composed of cells.
  • Theodor Schwann, a zoologist, further extended the theory to animals in 1839, in Microscopical Researches.
  • Rudolf Virchow, a physician, refined the cell theory in 1855, famously stating "omnis cellula e cellula" (every cell arises from another cell). This clarified that cells originate from preexisting cells, not from a non-cellular substance.

Three Tenets of Cell Theory

  • All living organisms are composed of one or more cells.
  • The cell is the basic unit of structure and organization in organisms.
  • Cells arise from pre-existing cells.

Modern Cell Classification

  • Cells are now classified into three domains: Bacteria, Archaea, and Eukarya.
  • Prokaryotes (Bacteria and Archaea) lack a nucleus.
  • Eukaryotes (Eukarya) possess a nucleus.

Prokaryotic Cell Structure

  • Prokaryotic cells are characterized by their simple structure.
  • Typical components include a plasma membrane, cell wall, DNA contained in a nucleoid region, ribosomes, and sometimes flagella or fimbriae/pili.

Bacteria Domain Examples

  • Escherichia coli, Streptococcus species, Salmonella species, and Bacillus species are examples of bacteria.

Archaea Domain Examples

  • Methanogens (obtaining energy from hydrogen and converting CO₂ into methane), halophiles (habiting extremely salty environments), and thermophiles (existing in acidic hot springs) are examples of archaea.

Eukaryotic Cell Structure

  • Eukaryotic cells are more complex and larger than prokaryotic cells.
  • Various membrane-bound organelles, a nucleus, and other specialized structures are characteristic features.

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Description

Explore the fundamentals of cell biology, including its structure, functions, and the significant contributions of Robert Hooke. Learn about the foundational concepts of cells as the basic units of life and Hooke's pioneering work in microscopy and his role in naming cells. This quiz covers both prokaryotic and eukaryotic cells as well as historical scientific discoveries.

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Biology Chapter 5: The Fundamental Unit of Life

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PowerfulEpigram
Hücreler ve Robert Hooke
30 questions

Hücreler ve Robert Hooke

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