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What characteristic distinguishes eukaryotic cells from prokaryotic cells?
What characteristic distinguishes eukaryotic cells from prokaryotic cells?
What are the primary constituents of membrane lipids?
What are the primary constituents of membrane lipids?
Which of the following is a function of the cell membrane?
Which of the following is a function of the cell membrane?
Which type of protein in the plasma membrane primarily functions to transport substances across the membrane?
Which type of protein in the plasma membrane primarily functions to transport substances across the membrane?
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What is the composition ratio of proteins to carbohydrates in cell membranes by dry weight?
What is the composition ratio of proteins to carbohydrates in cell membranes by dry weight?
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Which lipid component of cell membranes has hydrophilic heads and hydrophobic tails?
Which lipid component of cell membranes has hydrophilic heads and hydrophobic tails?
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What is the role of cholesterol in the cell membrane?
What is the role of cholesterol in the cell membrane?
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Which structure acts as the 'self-destruct' system within a eukaryotic cell?
Which structure acts as the 'self-destruct' system within a eukaryotic cell?
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What is essential for the plasma membrane to perform selective interactions with the environment?
What is essential for the plasma membrane to perform selective interactions with the environment?
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What type of cell lacks a defined nucleus?
What type of cell lacks a defined nucleus?
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What role do glycoproteins play in cell recognition?
What role do glycoproteins play in cell recognition?
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Which process allows for the selective transport of ions across the cell membrane?
Which process allows for the selective transport of ions across the cell membrane?
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Which scientist is credited with the discovery of the nucleus?
Which scientist is credited with the discovery of the nucleus?
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What is the main function of the cell membrane receptors?
What is the main function of the cell membrane receptors?
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What did Robert Hooke discover when he examined cork under a microscope?
What did Robert Hooke discover when he examined cork under a microscope?
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What explains why macrophages destroy worn-out erythrocytes?
What explains why macrophages destroy worn-out erythrocytes?
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What is synthesized by ribosomes and released into the lumen of the ER?
What is synthesized by ribosomes and released into the lumen of the ER?
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Which of the following was a significant contribution of Matthias Schleiden?
Which of the following was a significant contribution of Matthias Schleiden?
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Which hormone receptors are located in the cytoplasm?
Which hormone receptors are located in the cytoplasm?
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What did Rudolph Virchow contribute to cell theory?
What did Rudolph Virchow contribute to cell theory?
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What is the primary function of lysosomes?
What is the primary function of lysosomes?
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Which of the following statements about mitochondria is true?
Which of the following statements about mitochondria is true?
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What is the main role of centrioles during cell division?
What is the main role of centrioles during cell division?
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What is the function of vacuoles in plant cells?
What is the function of vacuoles in plant cells?
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Where does the Krebs cycle primarily occur?
Where does the Krebs cycle primarily occur?
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How do lysosomes contribute to cellular processes?
How do lysosomes contribute to cellular processes?
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What characterizes the outer membrane of mitochondria?
What characterizes the outer membrane of mitochondria?
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Which structure is only found in animal cells?
Which structure is only found in animal cells?
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What is the pH of blood when a total concentration of $H_2CO_3$ is at 1.2 meq/L?
What is the pH of blood when a total concentration of $H_2CO_3$ is at 1.2 meq/L?
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How does the pH of blood change when the concentration of bicarbonate increases while CO2 concentration remains constant?
How does the pH of blood change when the concentration of bicarbonate increases while CO2 concentration remains constant?
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What is the correct value of $pK_a$ for the bicarbonate buffer system given that $H_2CO_3$ equilibrium is considered?
What is the correct value of $pK_a$ for the bicarbonate buffer system given that $H_2CO_3$ equilibrium is considered?
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In respiratory alkalosis, what happens to the ratio of [HCO3-] to [CO2] during hyperventilation?
In respiratory alkalosis, what happens to the ratio of [HCO3-] to [CO2] during hyperventilation?
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How many meq of acid must be added to achieve a pH of 6.8 starting from a normal concentration of bicarbonate?
How many meq of acid must be added to achieve a pH of 6.8 starting from a normal concentration of bicarbonate?
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What is the total concentration of CO2 in blood expressed in meq/L for an individual with a PCO2 of 20.7 mmHg?
What is the total concentration of CO2 in blood expressed in meq/L for an individual with a PCO2 of 20.7 mmHg?
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If an individual’s blood pH returns from 7.6 to 7.4, what will the PCO2 be in mmHg?
If an individual’s blood pH returns from 7.6 to 7.4, what will the PCO2 be in mmHg?
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What is the relationship between pH and bicarbonate concentration in the blood?
What is the relationship between pH and bicarbonate concentration in the blood?
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What is the primary function of the nucleolus within the nucleus?
What is the primary function of the nucleolus within the nucleus?
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What type of endoplasmic reticulum is involved in the synthesis of proteins for secretion?
What type of endoplasmic reticulum is involved in the synthesis of proteins for secretion?
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Which structure acts as the 'protein factory' of the cell?
Which structure acts as the 'protein factory' of the cell?
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What is the main role of the Golgi complex in relation to the proteins synthesized by ribosomes?
What is the main role of the Golgi complex in relation to the proteins synthesized by ribosomes?
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What describes the internal structure of the endoplasmic reticulum?
What describes the internal structure of the endoplasmic reticulum?
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What distinguishes smooth endoplasmic reticulum from rough endoplasmic reticulum?
What distinguishes smooth endoplasmic reticulum from rough endoplasmic reticulum?
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How is genetic information organized within the nucleus?
How is genetic information organized within the nucleus?
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What component is essential for metabolic pathways like fatty acid synthesis found in the smooth endoplasmic reticulum?
What component is essential for metabolic pathways like fatty acid synthesis found in the smooth endoplasmic reticulum?
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Study Notes
The Cell's Nucleus and Cytoplasm
- The nucleus acts as the cell's control center, regulating a limited amount of cytoplasm.
- Typical cell sizes range from 5-50 micrometers in diameter.
Prokaryotic Cells
- Lack a nucleus and have nuclear material not enclosed by a membrane.
- Generally smaller than eukaryotic cells and are primarily single-celled organisms.
- Include bacteria and cyanobacteria, which contain genetic material in regions known as nucleoids.
Eukaryotic Cells
- Feature a defined nucleus and an extensive internal structure, including organelles.
- Organelles include transport systems, power plants (like mitochondria), and packaging centers (like the Golgi apparatus).
Plasma Membrane
- Maintains internal environment and facilitates chemical reactions necessary for life.
- Comprised of a thin membrane (plasmalemma) which is essential for selective interactions.
- Structurally complex, containing lipoproteins, carbohydrates, and various membrane systems.
Membrane Composition
- Cell membranes are around 10 nm thick with 60% protein and 40% carbohydrate by dry weight.
- Membrane lipids are polar, having a hydrophilic head and hydrophobic tails, primarily phospholipids, glycolipids, and cholesterol.
Protein Classes in Membranes
- Membrane proteins include structural proteins, enzymes, and carrier proteins.
- Carrier proteins transport substances across the membrane against concentration gradients.
Functions of Cell Membrane
- Acts as an active component, not just a protective barrier.
- Regulates material traffic and facilitates processes like transport, signal transduction, and cell recognition.
- Cell membrane glycoproteins serve as identity markers, aiding in cell recognition.
Cell Signaling and Hormone Reception
- Contains receptors for hormones that trigger metabolic changes within the cell.
- Steroid hormone receptors are positioned in the cytoplasm, while others reside in the plasma membrane.
Secretion Mechanism
- Polypeptides are synthesized in ribosomes, transported to the Golgi apparatus, stored in vesicles, and released to the cell exterior.
Historical Milestones in Cell Biology
- The first compound microscope was invented in 1590 by Hans and Zacharias Janssen.
- Robert Hook coined the term "cells" in 1665 after observing cork.
- Anton Van Leeuwenhoek observed living cells in 1673.
- Cell theory was developed by Schleiden, Schwann, and Virchow, stating all living organisms are composed of cells.
Modern Cell Theory
- All living organisms consist of cells; cells are the fundamental unit of life, originating from pre-existing cells.
Nucleus Structure
- The largest organelle, enclosed by a double membrane with nuclear pores, containing chromatin for DNA and RNA processes.
- Houses the nucleolus, responsible for ribosomal RNA production.
Endoplasmic Reticulum (ER)
- Composed of smooth and rough types; smooth ER is involved in lipid synthesis and rough ER contains ribosomes for protein synthesis.
Ribosomes
- Non-membranous structures where protein synthesis occurs; can be free-floating or attached to the ER.
Golgi Complex
- Modifies, packages, and transports proteins and materials out of the cell; works in conjunction with ribosomes and ER.
Lysosomes
- Contain hydrolytic enzymes for degrading macromolecules; involved in cellular digestion and recycling.
Mitochondria
- Known as the powerhouses of eukaryotic cells; involved in ATP production and contain their own DNA.
Centrioles
- Present only in animal cells; help in cell division by forming the mitotic spindle.
Vacuoles
- Fluid-filled sacs for storage; large central vacuoles in plant cells store various substances, while minimal or none are present in animal cells.
Cytoplasm
- The intracellular space surrounding organelles, with the soluble portion referred to as cytosol.
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Description
Explore the fascinating world of cell biology with a focus on the cell's nucleus and its crucial role in cellular activity. This quiz covers the differences between prokaryotic and eukaryotic cells, including their sizes and structures. Test your knowledge on cell organization and gain a deeper understanding of these fundamental units of life.
