Chapter 3- Cells & How they Work Flashcards
Cell Theory
- Cells are the smallest unit with properties of life
- All organisms consist of one or more cells
- Cells come from pre-existing ones
Basic Cell Structure
- Outer plasma membrane
- Cytomplasm
- DNA
Plasma Membrane
- Covering that encloses a cell’s internal parts
- Composed of lipids and lipids–bilayer
- Thin and fluid like
- Encloses the cell
- Controls movement of substances in and out (selectively permeable)
- Proteins in cell membranes carry out many functions (enzymes, receptors, and transport proteins)
Cytoplasm
Contents of cell between the outer plasma membrane and the nucleus. (Hand sanitizer consistency)
Cytosol
Jelly like fluid portion in the cytoplasm
Prokaryotic Cells
- Plasma membrane
- No nucleus
- Cytoplasm: fluid within membrane
- No true organelles
- Bacteria cells are prokaryotic
- BEFORE NUCLEUS
Eukaryotic Cells
- Plasma membrane
- Nucleus: membrane bound information center
- Cytoplasm: fluid within membrane
- Organelles: membrane bound structures with specialized functions
- All human cells are eukaryotic
- TRUE NUCLEUS
Surface-to Volume Ratio
Physical relationship by which the volume of a growing 3D object increases faster than its surface area does.
- Most cells have large surface area compared to their volume which allows for nutrients to easily pas through plasma membrane, into cell. And allows waste products to exit quickly.
- Small size= more surface area= more efficiency moving things into/out of cell and through the cell.
Importance of Membranes
- To be a filter (semi-permeable)
- Made up of phosphate and lipid bilayer
- Hydrophobic tail= water hating (does not dissolve)
- Hydrophilic tail= water loving
- ” Heads” are dissolved in watery fluids in/out of cell
Organelles
- Interior of a eukaryotic cell
- Specialized part of a cell having a specific function
- Outer membrane separates interior of organelle from rest of cytoplasm
- Membrane controls types of substances that enter and leave
- Most organelles surrounded by membranes (not all, through)
- Chemical reaction takes place in organelles
Organelles with Membrane
-Nucleus- protecting controlling access to DNA
Endoplasmic Recticulum (ER)- routing, modifying new polypeptide chains; synthesizes lipids, other tasks (SMOOTH AND ROUGH ER)
- Golgi Body- modifying new polypeptide chains; sorting, shipping proteins, and lipids
- Vesicles- transporting, storing, or digesting substances in a cell; other functions
- Mitochonrion- making ATP by sugar breakdown
- Lysosome– intracellular digestion
- Peroxisome- inactivating toxins
Organelles w/o Membrane
- Ribosomes- assembling polypeptide chains
- Centriole- anchor for cytoskeleton
Nucleus
Function:
- Controls everything/ brain of cell
- Contains genetic information of cell
- Controls all of the activities of the cell
Structural features:
- Doubled- layered nuclear membrane/envelope
- Nuclear pores ( allows material to pass through)
- Chromosomes/chromatin (DNA) ( DNA goes through pores)
- Nucleolus- within nucleus; parts of ribosomes assembled here)
Chromatin
Cell’s DNA and proteins associated with it
Grainy and threadlike, all stretched out
* DNA is organized in chromosomes
Chromsome
Double stranded DNA molecule that carries genetic information, compact
*DNA is organized in chromosomes
Endoplasmic Recticulum
- Flattened channel
- Starts at nuclear envelope and shakes through cytoplasm
- May be rough or smooth
- Lipid assembly and processing of polypeptide chains into proteins
Rough ER
Strutted with ribosomes; newly forming polypeptide chains that have built in signal (string of amino acids) can enter in space inside rough ER or incorporated into ER membranes
Smooth ER
Has no ribosomes, and curves through cytoplasm.
Ribosomes
- Attached to ER
- Platform for building cell proteins
- Ribosomes in rough ER = makes protein
Golgi Bodies
- Refines, packages, and ships
- Series of flattened sacs
Function: - Enzymes inside finish the proteins and lipids
- Package the molecules in yes circles for shipment to specific locations
Vesicles
Membrane-bound storage and shipping containers
Two main types:
- Peroxisomes
- Lysosomes
Peroxisomes
Contains enzymes that detoxify wastes produced by the cell (breakdown fatty acids and amino acids)
Lysosomes
Contains digestive enzymes that break down molecules
Mitochondria/ Mitochondrion
- Power plant of cell: the # of mitochondria in a cell varies with the cell’s energy requirement. ( If more energy is needed, more mitochondria is needed)
- Surrounded by a double membrane
- Inner membrane is highly folded
- Site of cellular respiration: utilizes O2 and produces CO2
- Generates ATP (energy)
- Have their own DNA= mtDNA ( DNA comes from Mom)
- We can’t survive without mitochondria
- MITOCHNONDRION- produces ATP; main cell fuel.
Cytoskeleton
- Internal structural framework (helps maintain shape)
- Cells have to have structures for support and movement
Parts of Cytoskeleton
- Microtubules: largest element of cytoskeleton, spatially organize interior of cell
- Microfilaments: filaments that reinforce cell parts
- Intermediate filaments: anchor proteins (actin/myosin) in systole and add strength.
Cell Structures that Enable Movement
- Cilia (Cilium)- short bendable structures; short brissles; rowers, built of microtubules. Shorter than flagella, short-many, many in respiratory tract (capture dust)
- Flagella (Fllagellum)- whiplike structures; moves itself. Nine pairs of microtubules ring a central pair, sakes and links provide structure, propel sperm, long and single.
- Centrioles- cell structures that give rise to microtubules
Concentration Gradient
A difference in # of molecules/ions from a region of higher concentration to a region of lower concentration (high–>low)
Diffusion
Movement of molecules from a region of high concentration to a region of low concentration
- High to low
- No energy needed
Passive Transport
- Transports a substance without having to expend ENERGY
- Diffusion of a substance across a cell membrane does not require ATP energy
- Diffusion- moving pieces
- Osmosis- only H2O moving
Passive Transport
- Transports a substance without having to expend ENERGY
- Diffusion of a substance across a cell membrane does not require ATP energy
- Diffusion- moving pieces
- Osmosis- only H2O moving
- AKA Facilitated diffusion
Active Transport
Cell must expend ENERGY from ATP
Movement of substance across cell membrane against concentration gradients.
-OPEN GATE
- Cells use more energy to move solutes against concentration gradients
Endocytosis
Entering into a cell
- Process which a cell takes in a larger molecule/ particle by forming a vesicle that encloses it and moves it in the cell cytoplasm
Exocytosis
Exiting from cell
- Vesicle encloses and moves a larger molecule or particle to cell surface and expels it.
Osmosis
Diffusion of water across a semipermeable membrane in response to solute concentration gradients
- Hypotonic
- Hypertonic
Osmosis
Diffusion of water across a semipermeable membrane in response to solute concentration gradients
- Water that moves through membrane= osmosis
- Hypotonic
- Hypertonic
Hypertonic
Fluid has more solutes on other side of selective permeable membrane.
- Water always tends to move from a hypotonic solution to a hypersonic solution because it always moves down its’s concentration gradient
Phagocytosis
Cell eating
Tranporter Proteins
(Friend that got you in)
- Helps solutes cross membranes
- Specific to a solute
- Provides a channel
Metabolism
Sum of all chemical reactions in an organisms
- Anabolism+ Catabolism= Metabolism
- Two types of metabolic pathways: anabolism and catabolism
Anabolism
- Larger molecules are assembled from smaller ones
- Requires energy- ATP input
- Makes big things
Catabolism
- Larger molecules are broken down to smaller ones.
- Releases energy- ATP output
- Breaks things
Cell Use & Transform Matter & Energy
Metabolic activities of a living cell require a lot of energy
Engird is often provided by catabolism-breakdown energy
ATPADP+P1+ energy
- Every chemical reaction requires a specific enzyme
Enzymes
- Essential part of metabolic reactions
- Enzymes are reusable
- Most enzymes are proteins and are all catalysts ( substance that causes or accelerates a chemical reaction without itself being affected)
- Enzyme that is substrate interact at the enzyme’s active site.
Why Cells Make ATP?
- Glucose (food) provides cell with energy
- Energy in glucose is used to generate ATP
- One glucose molecule may yield 36 ATP
- In absence of glucose, other carbohydrates, fats, and proteins can be catabolized to generate ATP
- ATP= more readily used “cash” form of energy (ie gold bricks vs. paper dollars; gold-> cash)
- Glucose and other fuel molecules must be cashed in for ATP can then be used to do cellular work
How Cells Make ATP?
Cellular Respiration
Glucose–>glycolysis–>krebs cycle–>electron transport system.
Substrates
Particular kind of molecule that interacts with a given enzyme.
Active Site
Area on surface where the enzyme and its substrate can interact.
Cellular Respiration
The breakdown of glucose int eh presence of oxygen to yield ATP (energy).
Cellular Respiration
The breakdown of glucose int eh presence of oxygen to yield ATP (energy).
Glycolysis
Breaks down glucose into pyuvate ( happens in cytoplasm, outside of mitochondrion).
Krebs Cycle
Produces energy-rich transport molecules ( in mithochondrion).
Electron Transport
Produces many ATP molecules ( 1 glucose= 36 ATP)
