Term
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Definition
| -In its modern form, the cell theory includes three principles:
-1. All organisms are composed of one or more cells
2. Cells are the smallest living things
3. Cells arise only by division of a previously existing cell |
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Term
| What are the two major kinds of cells? |
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Definition
| -Prokaryotic Cells:
Only Bacteria Cells
Have no nucleus
-Eukaryotic Cells:
Fungi , plants , animals, protist
A nucleus is present |
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Term
| What are the cell types based on structure? |
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Definition
| 3 cell type based on structure:
1. Bacteria or Prokaryotic cell ( prokaryotes)
2. Animal cells ( eukaryotes)
3. Plant cells (eukaryotes) |
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Term
| What are the General Cell Features? (What all cells have) |
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Definition
| 1. Cell membrane ( plasma membrane)
2. Cytoplasm
3. DNA
[image] |
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Term
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Definition
| -Bacteria Cell
-Prokaryotes include bacteria and archaea
-Over 5,000 species are recognized
-Prokaryotes come in three main shapes:
---spiral
---rod
---spherical |
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Term
| Prokaryote cell sturucture |
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Definition
| -They lack a nucleus and organelles.
[image] |
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Term
| List of Prokaryotic cell structures |
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Definition
| Capsule
Cell Wall
Plasma membrane ( cell membrane)
Pilus
Flagella
DNA ( nucleoid region , bacteria chromosome)
Cytoplasm
Ribosomes |
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Term
| Prokaryotic Cell: Capsule |
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Definition
| This is a protective layer around the bacteria. It is usually present in disease-causing bacteria. |
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Term
| Prokaryotic Cell: cell wall |
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Definition
| There are two basic types of cell walls, Gram positive and Gram negative. The cell wall is a rigid layer that gives the bacteria protection and its shape. |
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Term
| Prokaryotic Cell: Plasma Membrane |
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Definition
| This is a semi-permeable layer around cell |
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Term
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Definition
| This is where most of the bacteria's genetic information is stored. |
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Term
| Prokaryotic Cell: Cytoplasm |
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Definition
| liquid material inside the cell. |
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Term
| Prokaryotic Cell: Ribosome |
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Definition
| Ribosomes are involved in making proteins. |
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Term
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Definition
| Some bacteria have pili. Pili are used for adhesion to surfaces. |
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Term
| Prokaryotic Cells: Flagellum |
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Definition
| Some bacteria have flagella so that they can move around in their environment. |
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Term
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Definition
| -Include all cells alive today except bacteria and archaea
-Are larger than prokaryotic cells
-Have a much more complex architecture
Possess nucleus and a variety of membrane bound organelles |
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Term
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Definition
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Term
| What is the Plasma Membrane? |
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Definition
| -Encases all living cells
-Its basic structure is represented by the fluid-mosaic model
Phospholipid bilayer with embedded proteins |
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Term
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Definition
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Term
| What does the plasma membrane contain? |
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Definition
| -A bi-layer
- Zones called lipid rafts (heavily enrihed in cholesterol. |
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Term
| Proteins Within the Membrane |
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Definition
| Two main types:
-Cell-surface proteins
Project from the surface of the membrane
Act as markers or receptors
-Transmembrane proteins
Extend all the way across the bilayer
Provide channels in and out of the cell |
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Term
| The Nucleus: The Cell’s Control Center |
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Definition
| -The nucleus is the command center of the cell
-It directs all of its activities
-It also stores the cell’s hereditary information
-The DNA is associated with proteins (histones)
-During cell division, it condenses into chromosomes
-After cell division, it relaxes to form chromatin |
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Term
| The Endomembrane System and what does it consist of? |
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Definition
| -An extensive system of interior membranes that divides the cell into compartments
-It consists of:
Endoplasmic reticulum
Golgi complex
Lysosomes
Peroxisomes |
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Term
| Endoplasmic Reticulum (ER) |
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Definition
| -Internal membrane system creating channels and membrane-bound vesicles
-Consists of two distinct regions
Rough ER
Studded with ribosomes
Involved in protein synthesis
-Smooth ER
Embedded with enzymes
Involved in lipid and carbohydrate synthesis |
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Term
| Where does the molecules transport to from the ER? |
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Definition
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Term
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Definition
| -Golgi bodies are flattened stack of membranes that are scattered throughout the cytoplasm
-Depending on the cell, the number of Golgi bodies ranges from a few to several hundred
-These are collectively referred to as the Golgi complex
-The Golgi complex collects, packages, modifies and distributes molecules |
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Term
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Definition
| -Arise from the Golgi complex
-They contain enzymes that break down macromolecules
-Function in intracellular digestion of
Worn-out cellular components
Substances taken into cells
-The resulting material is then recycled |
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Term
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Definition
| -Arise from the ER
-They contain two sets of enzymes
-One set is found in plants
Converts fats to sugars
-The other set is found in animals
Detoxifies various harmful molecules |
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Term
| Organelles That Contain DNA |
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Definition
| -Two cell-like organelles contain DNA
-Mitochondria
Found in almost all eukaryotes
-Chloroplasts
Found only in plants and algae |
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Term
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Definition
| -Powerhouses of the cell
Extract energy from organic molecules through oxidative metabolism
-Sausage-shaped organelles, about the size of a bacterial cell
-Like bacteria, they
1. Possess circular DNA
2. Divide by simple fission |
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Term
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Definition
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Term
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Definition
| -Energy-capturing centers
Sites of photosynthesis in plants and algae
-Like bacteria, they
1. Possess circular DNA
2. Divide by simple fission
-Like mitochondria, they are surrounded by two membranes |
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Term
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Definition
| -Energy-capturing centers
Sites of photosynthesis in plants and algae
-Like bacteria, they
1. Possess circular DNA
2. Divide by simple fission
-Like mitochondria, they are surrounded by two membranes |
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Term
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Definition
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Term
| The Cytoskeleton: Interior Framework of the Cell |
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Definition
| -A dense network of protein fibers that
1. Supports the shape of the cell
2. Anchors organelles
-Three different kinds of protein fibers:
1. Microfilaments
2. Microtubules
3.Intermediate filaments |
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Term
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Definition
| -Anchor and assemble microtubules
-Not found in higher plants and fungi |
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Term
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Definition
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Term
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Definition
| -Essentially, all cell motion is tied to the movement of microfilaments and microtubules
-Changes in the shape of microfilaments
Enable some cells to change shape quickly
-Allow some cells to crawl
-Cause animal cells to divide |
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Term
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Definition
| -Flagella and cilia (only in animal cells)
-Flagella: Long and few in number
-Cilia: Short and numerous |
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Term
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Definition
| -In plants
Store dissolved substances, water
Can increase the cell’s surface area
-In protists
Contractile vacuoles are used to pump excess water |
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Term
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Definition
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Term
| Outside the Plasma Membrane |
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Definition
| Cell Walls
-Offer protection and support
-Fungal cell walls are made up of chitin
-Plant cell walls are made up of cellulose |
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Term
| Outside the Plasma Membrane (2) |
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Definition
| Extracellular Matrix
-A mixture of glycoproteins secreted by animal cells
-Helps coordinate the behavior of all cells in a tissue |
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Term
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Definition
| Prokaryotes
-No nucleus
-No membrane bound organelles
Eukaryotes
-Nucleus
-Organelles ; chloroplast , mitochondria , golgi , lysosome . etc . |
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Term
| Comparing Animal and Plant Cells |
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Definition
| -Animal Cells:
No cell wall
No chloroplast
No large central vacuole
centrioles
-Plant Cells:
Cell wall
Chloroplast-photosynthesis
Large central vacuole
No centrioles |
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Term
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Definition
| -Water and other small molecules cross into or out of cells.
-All cells acquire the molecules and ions they need from their surrounding extracellular fluid (ECF).
-There is an unceasing traffic of molecules and ions |
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Term
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Definition
| -Passive Transport
Molecules and ions move spontaneously down their concentration gradient (i.e., from a region of higher to a region of lower concentration).
-Active transport
Molecules and ions can be moved against their concentration gradient, but this process, called active transport, requires the expenditure of energy (usually from ATP). |
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Term
| What is diffusion and osmosis? |
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Definition
| -Diffusion is the movement of molecules (solutes) down their concentration gradient
-Solute transport is from left to right. |
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Term
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Definition
| -Movement of water through a semi-permeable membrane
-Solutes are substances dissolved in a solution
Hyperosmotic solution contains higher concentration of solutes than the cell
Hypoosmotic solution contains lower concentration of solutes than the cell
Isotonic solution contains equal concentration of solutes as the cell |
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Term
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Definition
| Movement of water into a cell creates osmotic pressure, this can cause a cell to swell and burst |
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Term
| Bulk Passage into and out of Cells |
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Definition
| -Large amounts of material can be moved in and out of cells by membrane-bound vesicles
-Exocytosis
Discharge of material from vesicles at the cell surface
-Endocytosis
The plasma membrane envelops particles and brings them into the cell interior |
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Term
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Definition
| Means by which hormones, neurotransmitters and digestive enzymes are secreted in animal cells
[image] |
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Term
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Definition
| 1. Phagocytosis
Engulfment of particulate material
2. Pinocytosis
Engulfment of liquid material
All are "eaten" by cytoplasm. |
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Term
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Definition
| Cell membranes have selective permeability
They contain protein channels that allow only certain molecules to pass
Selective Diffusion
Allows molecules to pass through open channels in either direction
Ion channels
If the ion fits the pore, it goes through |
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Term
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Definition
| Net movement of a molecule down its concentration gradient facilitated by specific carrier proteins |
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Term
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Definition
| The movement of molecules across a membrane against a concentration gradient
This is possible by the expenditure of energy
Two types of channels are mainly used
1. Sodium-Potassium Pump
2. Proton Pump |
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Term
| The Sodium-Potassium Pump |
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Definition
| Uses the energy of one ATP molecule to pump 3 Na+ outward and 2 K+ into the cell |
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Term
| The Sodium-Potassium Pump |
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Definition
| Leads to fewer Na+ in the cell
This concentration gradient is exploited in many ways, including
1. The conduction of signals along nerve cells
2. The transport of material into the cell against their concentration gradient: Coupled channels |
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Term
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Definition
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Term
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Definition
| Expends metabolic energy to pump protons across membranes
[image] |
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