CH 6 Cell Theory Lecture Flashcards
Three main parts of Cell Theory
**Basic Unit of Life
**Composition of Living Organisms
**Cellular Reproduction
Life begins at the _____
cellular level
Cellular Reproduction
Cells arise from pre-existing cells through cell division (copying), which allows for growth and the creation of new cells.
______ are the fundamental unit of all living organisms.
Cells are the fundamental unit of all living organisms.
All cells can be divided into two categories
Prokaryotic cells, and Eukaryotic cells
A cell that contains membrane-bound organelles with phospholipid bilayers
Eukaryotic Cells
A type of cell that has structures that perform specific tasks but doesn’t have membrane that surrounds them
Prokaryotic Cells
All their cellular processes, metabolic reactions, or macromolecules creation occurs in the cytoplasm
Prokaryotic Cells
-Metabolic reactions mainly occur within organelles
Eukaryotic Cells
The membrane-bound organelles structure allows them to become part of multicellular organisms and specialize their activities
Eukaryotic Cells
Always single-celled, never become multi-celled organisms
Prokaryotic Cells
_____ cells are found in organisms like bacteria and archaea.
Prokaryotic cells
They outnumber eukaryotic cells by trillions, but they are microscopic and single-celled.
Most life on Earth is _______.
Prokaryotic cells
Have cell membrane and internal components, without cell walls
Eukaryotic cells in Animals, Protozoa
Have cell wall, cell membrane, cytoplasm, and internal components with cell walls
Eukaryotic cells in Plants, Fungi, Algae
All living organisms must consist of _______ to be considered alive
one of more cells
Basic Components of Cells (4)
**Cell Membrane
**Cytoplasm
**DNA
**Organelles
—->Not all cells have organelles, but eukaryotic cells do.
Composed of phospholipids, controls what enters and exits the cell.
Cell Membrane
Thick jelly-like primarily water, contains macromolecules (proteins, sugars, and some DNA) and various structures.
Everything inside the cell
Cytoplasm
Stores genetic information, drives protein production
DNA
small specialized structures within cells with specific functions.
Organelles
**Not all cells have organelles, but eukaryotic cells do.
lack organelles surrounded by membranes.
No membrane-bound organelles:
Prokaryotic Cells like bacteria and archaea.
Have various specialized structures (like the nucleus, mitochondria, etc.) that perform specific functions.
Eukaryotic Cells
Size Range: 1-100 µm
Size Range: 0.1-10 µm
Eukaryotic Cells
Prokaryotic Cells
Name and explain the 2 major events that are thought to have occurred in the endosymbiotic theory.
- Folding in of the cell membrane to make organelles
- Engulfing of cells that eventually became
organelles
Explain what the constraint on the size of the cell is (why are almost all cells microscopic)?
Cell size is limited by the constraints of the cell surface area to volume ratio.
As a cell increases in size, its surface area does not increase proportionately to its increase in volume.
Cells need to move nutrients into the cell and excrete waste products back out. Cells larger than 500 microns do not have enough surface area to maintain cell function.
Cells tend to be very small in order to increase their surface area in relation to their volume, this helps to absorb enough nutrients from their surroundings.
What are the molecules that make up the cell membrane?
Proteins, Sterols and Phospholipids
The outermost layer found in Eukaryotic cells
Cell membrane/ phospholipid bylayer
Separates the inside of the cell (cytoplasm) from the outside world (extracellular fluid).
Cell membrane/ phospholipid bylayer
It regulates what enters and exits the cell, protecting the cell from toxins and allowing it to remove waste.
Cell membrane/ phospholipid bylayer
provides support in the cell membrane.
Has various roles, such as transporting molecules, stabilizing the membrane, or acting as cell markers for communication with other cells.
Proteins
Ring Lipid molecules that provide extra flexibility and stability to the cell membrane.
Prevents the membrane from becoming too rigid or too fluid.
Sterols (e.g. Cholesterols)
Sandwich structure for the cell membrane, hydrophilic (water-loving) heads face outward and hydrophobic (water-hating) tails face inward.
Phospholipid bilayer
The biggest in term of volume in the cell
Cytoplasm
Provides aqueous solution for metabolic reactions to take place
Cytoplasm
Composition:
Primarily water
Proteins, carbohydrates, lipids, salts, acids, bases, etc.
Used to help keep the cell alive providing nutrients and substances it needs
Cytoplasm
It also provides structural support for the cell’s internal structures.
Cytoplasm
It’s mainly water but also contains various molecules like proteins, lipids, and sugars, which support the cell’s metabolic activities (chemical reactions).
cytoplasm
It provides structural support, metabolic reactions, keeps the cell alive, provides nutrients and substances
Cytoplasm
Has a network of protein fibers that runs through the cytoplasm and attaches to the plasma membrane, and various structures and organelles within the cell
Cytoskeleton
Serves like a bunch of roads that macromolecules can be transported through and signals can be sent along, allows one part of the cell to be in touch with another part of the cell
Cytoskeleton
Three groups of proteins fiber groups that make up the cytoskeleton are
**Microtubules
**Microfilaments
**Intermediate filaments
extend throughout the cytoplasm provides support assist in transport functions
(Cytoskeleton, Protein fiber type)
Microtubules: Tubulin …. Hollow tubes:
made of Actin
Two strands (actin wrapping around each other)
They are responsible for movement and helping the cell rearrange its shape.
(Cytoskeleton, Protein fiber type)
Microfilaments
Often attached to the microtubules to support their activities
Intermediate filaments
Strong, coiled structures that provide mechanical support and help anchor the other cytoskeletal elements.
Various types of filaments and proteins
Coiled around each other
Used primary for support
Often attached to the microtubules
(Cytoskeleton, Protein fiber type)
Intermediate filaments
largest organelle in most eukaryotes cells
Nucleus
specialized structures within the cell, each performing specific functions essential for the cell’s survival.
Organelles
A double membrane that surrounds the nucleus, providing protection and separation from the cytoplasm.
Nuclear Envelope
Stores and protects the cell’s DNA, which contains genetic instructions for cellular activities.
Nucleus
Plays a key role in the early stages of protein production (Protein Synthesis Initiation) by housing DNA templates for mRNA transcription.
Nucleus
The highest concentration of DNA is typically in the center of the nucleus called the
nucleolus
channels within this double membrane system that allows information from inside the nucleus to be transmitted to the outer part of the cell.
nuclear pores
-Double membrane system.
It’s holding the DNA and all kinds of proteins that are in here in the cytoplasm of the nucleus.
That DNA is going to be used to make proteins to start protein synthesis, and is going to be copied and passed off to the next generation.
nuclear envelope
Separates the genetic material (DNA) within the nucleus from the rest of the cell cytoplasm, ensuring proper regulation of gene expression and protein synthesis
nuclear envelope
The DNA arranged in chromosomes, associated with proteins make
chromatin
In the nucleus, a complex of DNA and associated proteins that forms chromosomes.
Chromatin
is loosely packed when the cell is not dividing (allowing gene expression) and condenses into visible chromosomes during cell division.
Chromatin
The endomembrane system is responsible for
the synthesis, modification, transport, and storage of macromolecules such as proteins, carbohydrates, and lipids.
Two main purposes for the Endomembrane System is
Create macromolecules
Transport macromolecules
The _______ system is responsible for the synthesis, modification, transport, and storage of macromolecules such as proteins, carbohydrates, and lipids.
endomembrane
Memebrane bound structures that contain macromolecules that will be used for some kind of function
Vesicles
Structures in the Endomembrane system that may or may not have a membrane around them, typically used for storage (water, nutrients, or cells)
Vacuoles
In plant cell, vacuoles help maintain structure and pressure
Often referred to as organelles but not membrane bound.
Ribosomes
Sites of protein synthesis, where genetic information (mRNA) is translated into a specific sequence of amino acids to form proteins.
Ribosomes
Composed of ribosomal RNA (rRNA) and proteins.
Not membrane-bound
Ribosomes
Made up of two subunits: a large and a small subunit.
The space between them is where proteins are assembled.
Ribosomes
Energy producing organelles
Mitochondria (Animal & Plant Cells):
Chloroplasts (Plant Cells & Some Algae):
Converts sunlight into chemical energy (glucose and ATP) via photosynthesis.
Chloroplasts (Plant Cells & Some Algae)
Generates ATP (adenosine triphosphate) through cellular respiration.
Converts glucose into ATP, the cell’s primary energy source.
Mitochondria (Animal & Plant Cells)
Known as the “energy currency” of the cell, storing and providing energy for cellular processes (growth, repair, movement).
Mitochondria uses sugar, Chloroplasts use sunlight
ATP (Adenosine Triphosphate)
The theory that Mitochondria & Chloroplasts organelles originated as free-living prokaryotic cells (bacteria) that were engulfed by a larger cell and developed a symbiotic relationship.
Endosymbiosis Theory
Cell Appendages, may stick out from the cell, locomotor structures, helps with movement
Flagella and Cillia
The Flagella and Cillia are the same on the inside possessing ____ to move
microtubeles
The ____ grabs on to something and brings it inside the cell
Cillia
Function: Provides support, protection, and communication for animal cells (which lack cell walls).
Composition: Primarily proteins (e.g., collagen).
Extracellular Matrix (ECM) (Animal Cells)
Rigid outer layer providing:
Structural support.
Shape maintenance.
Protection from damage & pathogens.
Water regulation (preventing excessive intake or loss).
Cell walls (Found in plants, fungi, algae)
Tubes that connect cytoplasm between neighboring plant cells
Plasmodesmata
Allow direct exchange of molecules for communication and coordination in plant cells
Plasmodesmata
In animal cells, Anchor cells together like spot welds.
Proteins from one cell with reach across and grab on to each other
Provide mechanical strength (e.g., in skin cells).
Desmosomes
In animal cells, Form a seal between neighboring cells.
Prevent leakage (e.g., in intestinal lining).
Tight Junctions
Protein channels connecting neighboring cells
Allow direct exchange of ions & small molecules for communication.
Gap Junctions:
(like plasmodesmata in plants).
Key Functions of the Endomembrane System:
—–Macromolecule Synthesis: Produces proteins, lipids, and carbohydrates.
——Transport & Processing: Ensures proper folding, modification, and distribution of macromolecules.
——-Storage & Secretion: Stores essential substances and helps release molecules into the extracellular environment.
Endomembrane System (five main parts)
- Nuclear Membrane (Envelope):
- Endoplasmic Reticulum (ER):
Rough ER (RER):
Smooth ER (SER): - Golgi Apparatus:
- Vesicles & Vacuoles:
- Cell Membrane (Plasma Membrane):
In the endomembrane system it
–>Transmits information
–>Encloses the nucleus and regulates information exchange between the nucleus and cytoplasm through nuclear pores.
Nuclear Membrane (Envelope)
the inner most part
` True/False: The endomembrane system includes the mitochondria because it processes macromolecules.
False
Explanation: The endomembrane system (nuclear envelope, ER, Golgi, vesicles, cell membrane) synthesizes, modifies, and transports macromolecules, but mitochondria are separate, energy-producing organelles from endosymbiosis, not part of this system. Trick: Tests boundary knowledge.
True or False: The smooth ER synthesizes carbohydrates for the cell membrane’s glycoproteins.
True
Explanation: The smooth ER synthesizes lipids and carbohydrates, including those added to proteins in the Golgi to form glycoproteins for the cell membrane. While the Golgi attaches them, the SER provides raw materials.
How do vesicles and vacuoles contribute to the storage and secretion functions of the endomembrane system?
Vesicles are small, membrane-bound sacs that transport macromolecules between endomembrane components (e.g., RER to Golgi, Golgi to cell membrane) and secrete them outside via exocytosis (e.g., hormones). Vacuoles, larger sacs, store substances like water, nutrients, or waste; in plant cells, the central vacuole maintains turgor pressure. Both originate from the Golgi or cell membrane and support the system’s storage and secretion roles.
Explanation: Differentiates their roles while linking to broader functions.
Explain how the rough ER and smooth ER differ in structure and function within the endomembrane system.
The rough ER (RER) has ribosomes on its surface, giving it a “rough” appearance, and functions in protein synthesis and folding for secretion or membrane use. The smooth ER (SER) lacks ribosomes, appearing smooth, and synthesizes lipids (e.g., phospholipids, steroids) and detoxifies substances (e.g., drugs in liver cells). Both are continuous membranes, but RER focuses on proteins, while SER handles lipids and detoxification.
Describe the role of the Golgi apparatus in the endomembrane system and how it interacts with other components.
The Golgi apparatus modifies, packages, and distributes macromolecules received from the rough ER. It adds carbohydrate groups (glycosylation) or other modifications to proteins and lipids, then sorts them into vesicles. These vesicles may travel to the cell membrane for secretion (exocytosis) or to other organelles (e.g., vacuoles). It interacts with the RER by receiving vesicles with newly synthesized proteins and with the cell membrane by sending vesicles for export.
Explanation:
What is the final destination for many macromolecules processed by the endomembrane system?
A) Cytoplasm
B) Mitochondria
C) Extracellular environment
D) Nucleus
C) Extracellular environment
Explanation: Many macromolecules (e.g., hormones, enzymes) are secreted outside the cell via exocytosis, where vesicles fuse with the cell membrane (plasma membrane), a key endomembrane component.
Which organelle in the endomembrane system does NOT directly modify macromolecules?
A) Rough ER
B) Golgi apparatus
C) Nuclear envelope
D) Vesicles
C) Nuclear envelope
Explanation: The nuclear envelope regulates transport but doesn’t modify macromolecules. The RER folds proteins, the Golgi modifies them further (e.g., adds sugars), and vesicles transport them, but the envelope’s role is structural and regulatory. Trick: Tests if you distinguish modification from transport.
Which part of the endomembrane system detoxifies harmful substances like drugs in liver cells?
A) Rough ER
B) Smooth ER
C) Golgi apparatus
D) Vesicles
B) Smooth ER
Explanation: The smooth ER (SER) lacks ribosomes and is involved in lipid synthesis and detoxification (e.g., breaking down toxins in liver cells), a specialized function distinct from protein synthesis.
What is the primary role of the nuclear envelope in the endomembrane system?
A) Synthesizes lipids
B) Regulates exchange between nucleus and cytoplasm
C) Packages proteins into vesicles
D) Stores carbohydrates
B) Regulates exchange between nucleus and cytoplasm
Explanation: The nuclear envelope, a double membrane with nuclear pores, controls the flow of molecules (e.g., mRNA, proteins) between the nucleus and cytoplasm, facilitating communication for protein synthesis.
Which component of the endomembrane system is directly responsible for the initial synthesis of proteins destined for secretion?
A) Golgi apparatus
B) Smooth ER
C) Rough ER
D) Nuclear envelope
C) Rough ER
Explanation: The rough ER (RER), studded with ribosomes, is the primary site for synthesizing proteins that will be secreted or inserted into membranes. The ribosomes translate mRNA into polypeptides, which the RER then folds and modifies.
Which cytoskeletal component is hollow and made of tubulin?
A) Microfilaments
B) Intermediate filaments
C) Microtubules
D) All of the above
C) Microtubules
Explanation: Microtubules are hollow tubes of tubulin; microfilaments (actin) and intermediate filaments (various proteins) have different structures.
Why are prokaryotic cells considered simpler than eukaryotic cells, despite their metabolic versatility?
Prokaryotic cells lack membrane-bound organelles and a nucleus, so all processes (e.g., metabolism) occur in the cytoplasm, making them structurally simpler. Eukaryotic cells have compartmentalized organelles for specialized tasks, increasing complexity, even though prokaryotes can perform diverse metabolic reactions.
Which statement is NOT part of traditional cell theory?
A) Cells are the basic unit of life
B) All living organisms are made of cells
C) Cells arise from pre-existing cells
D) Cells contain chloroplasts for energy
D) Cells contain chloroplasts for energy
Explanation: Cell theory doesn’t specify organelles like chloroplasts (only in plants/algae). Trick: Tests scope of the theory.
Draw and label a dehydration synthesis reaction forming maltose from two glucose molecules.
Two glucose molecules (C₆H₁₂O₆) → Maltose (C₁₂H₂₂O₁₁) + H₂O.
Label: Glucose (OH group), Glucose (H), glycosidic linkage, removed H₂O.
Explanation: Tests reaction mechanics and product identification.
Which nucleic acid component is present in DNA but NOT in RNA?
A) Adenine
B) Thymine
C) Ribose
D) Phosphate
B) Thymine
Explanation: DNA has thymine (T), while RNA has uracil (U). Trick: Ribose is in RNA, deoxyribose in DNA—don’t confuse sugar with base.
Describe the structural difference between a triglyceride and a phospholipid, and how this affects their function.
A triglyceride has glycerol bonded to three fatty acids via ester linkages, making it nonpolar and ideal for long-term energy storage. A phospholipid has glycerol with two fatty acids and a polar phosphate group, forming a hydrophilic head and hydrophobic tails, perfect for the cell membrane’s bilayer structure.
Which fatty acid feature causes unsaturated fats to be liquid at room temperature?
A) Full saturation with hydrogen
B) Cis double bonds creating kinks
C) Trans double bonds aligning tails
D) Ester linkages with glycerol
B) Cis double bonds creating kinks
Explanation: Unsaturated fats have cis double bonds, reducing tight packing and lowering the melting point (liquid at room temp). Trick: Distinguishes cis vs. trans configurations.
Which of the following is NOT a characteristic of most macromolecules?
A) Composed of SPONCH elements
B) Held together by covalent bonds
C) Easily soluble in water
D) Built from monomers into polymers
C) Easily soluble in water
Explanation: Most macromolecules (e.g., lipids, proteins) are nonpolar and hydrophobic, not easily soluble in water. Trick: Tests if you recall polarity’s impact on solubility.
