Cellular Biology
Whats An Enzyme?
Enzyme Inhibitors
The Bad
An example of this is a carbon monoxide
If a chemical bonds to stop a vital reaction it is a hazard
Sometimes inhibitors have a negative effect
What?
Competitive Inhibitors (A molecule other than the intended bonds to the active site)
Non- competitive Inhibitors ( A molecule bonds to a different site that then changes the shape of the active site)
2 types of inhibitors (Non-competitive inhibitors & Competitive inhibiitors)
Enzyme inhibitors control the amount of a product being made
Factors Affecting Enzymes
Ex, PH, Temperature
Because enzymes are proteins they can be damaged, or denatured
Importance Of Enzymes
How Do Enzymes Work?
Once the reaction has occurred the enzyme is ready to work again!
This puts the substrates in the best position for the reaction to occur
This also helps weaken existing bonds making it easier for products bonds to form
The place where a substrate connects is called the active site
How it works: Enzymes bond to the reactant molecules, also called substrates
Enzymes lower the activation energy of the specific reaction it's made for
All reactions that take place need energy to occur, activation energy
Because enzymes are a part of most reactions in a body problems can occur if an enzyme is missing or depleted
People can take a tablet to extract lactae
Without it the small intestine cannot digest lactose
Lactase helps break down lactose found in milk products
Humans who are lactose intolerant are missing the enzyme lactase
Enzymes are specialized proteins that help ensure biological reactions occur at the perfect rate for life
A substance that controls the rate of a reaction is called a catalyst
Catalysts in living things are called enzymes
Cells need a way to help control the chemical reactions, that's where enzymes come in
What Is Life Made Of?
Compounds: A pure substance made up of one or more elements combined chemically
Atoms are the smallest possible piece of an element other (Na, Mg, P, K)
Atoms: Humans and all things are made up of a combination of 52 elements
Plant Cells
Cell Wall
Mostly made of cellulose (fibre)
Helps give the plants structure and shape
Is strong and rigid
Surrounds the cell membrane
Only in PLANT CELLS!
Chloroplasts
Only in plant cells
Contains enzymes and other chemicals used in photosynthesis
Responsible for the green color of plants
Plants use chloroplasts to make their own food using photosynthesis
They often have one big vacuole called the central vacuole
Has cell walls
Has chloroplasts
Plant cells have a few main differences from animal cells
Plant cells are multicellular
Animal cells
Mitochondria
The powerhouse of the cell
The number of mitochondria differs, often there are hundred or thousands in cell
Converts nutrients into energy sing a series of reactions called cellular respiration
Made of a smooth outer membrane and an inner membrane with many folds
Lysosomes
Digest macromolecules (proteins, fats, etc)
Why Cells Need To Digest Macromolecules
Killing the cell. Simultaneous release of the contents of many lysosomes can kill a cell
Recycling cell components
After digesting the cell absorbs food particles. Lysosomes help break it down
To fight diseases lysosomes breakdown the macromolecules in bacteria killing it
Only in ANIMAL CELLS
Rough ER makes the membranes and enzymes and the Golgi body makes them into lysosomes
Containers or sacs that contain enzymes
Vacuoles
Smaller in animal cells (often more than one)
Very large in plant cells (often only one 80% it's volume called a central vacuole
Stores macromolecules and water
Act as storage compartments
Golgi Body
Some products include hormones or enzymes
Enzymes in each sac modify, store, and pack substances (in vesicles) made in the ER and sends like to places in or outside the cell
Each sac contains a different enzyme
A stack of containers or sacks
Endoplasmic Reticulum (ER)
Rough ER
Proteins made by the ribosomes collect in the rough ER
Appears rough when using an electron microscope
Smooth ER
Roles: Makes lipids and steroids, Breaks down toxins (liver cells), Releases calcium (important for muscle movement)
Named because of it's surface which appears smooth
Connected to the nucleus
Vesicles form when a cell or organelle membrane is pinched off
Substances made in the ER are transported by vesicles (small containers made of membrane)
2 different parts (smooth ER & rough ER)
The inside of the ER is separate from the inside of the nucleus
A netw
Many different types and they all look different Ex. Liver cells, Kidney cells, Stem cells, Blood cells, etc
Animal cells are multicellular meaning multiple cells work together to complete an organism
Ribosomes
Builds proteins (protein synthesis) and amino acids
Other ribosomes attach to the endoplasmic reticulum
Free ribosomes float in the cytoplasm
So small cannot be seen using a typical microscope
Produced in the nucleolus
Nucleus
Inside the nucleus is the nucleolus
Contain chromatin (the building blocks of chromosomes
DNA is also replicated here
The nucleus is surrounded by a nucleur envelope
Controls cell division (mitosis)
Regulates gene expression
Contains all the cell's genetic information in the of DNA
Made of phospholipid bilayer and proteins
Regulates what enters and exits the cell
Barrier that surrounds the cytosol of the cell
Cytoplasm
Everything that surrounds the nucleus
Includes: Cytosol- Everything inside the membrane except the nucleus
Cytoskeleton: Protein fibers and tubes that help the cell maintain structure
Organelles
Jelly like and mostly made of water
Cell Theory
All cells come from preexisting cells
The cell is the main unit of structure and organiztion in organisms
All living things are composed of one or more cells
Cell Membrane
We use the fluid mosaic model to describe the cell membrane
''Fluid'' refers to how the membrane moves. they stay together but are not fixed
Made up of a phospholipids bilayer, but not only phospholipids
Cell membranes are like the security or bouncers of a cell. They control what gets in and and out
Energy In The Cell
Fermentation: Anaerobic Respiration
Produces fewer ATP per glucose molecule compared to cellular respiration
This happens in human muscle cells
Lactic Acid Fermentation: Pyruvate forms lactic acid
Alcoholic fermentation: Pyruvate is converted to ethanol and carbon dioxide
Fermentation is one process that organisms can produce energy without oxygen
Photosynthesis
Plants still create more oxygen than they use
After creading glucose plant cells also go through cellular respiration
Photosynthesis takes place in the chloroplasts
Plants make their own food using photosynthesis
Cellular Aerobic Respiration
Other than ATP carbon dioxide and water are the products of this reaction
With 2 pyruvate from every glucose entering this stage 34 ATP are created at this stage
A series of reactions occur that involve oxygen
The pyruvate molecules created in glycolysis enter the mitochondria
Step 2: Oxidative Respiration takes place in the mitochondria
Creates 2 pyruvate (3 carbon molecule) and 2 ATP molecules for every glucose
6 carbon dioxide and 6 water produced
6 oxygen are consumed
ATP created per glucose molecule =36
This reaction is controlled by enzymes
Step 1: Glycolysis takes place in the cytosol
How Cells Use ATP
ATP goes through a chemical reaction that releases a burst of energy used by the cell
ADP creates adenosine diphosphate and free phosphate group
ATP is mucleotide made of adenosine and 3 phosphate groups
ATP (adenosine triphosphate)is the molecule cells use for energy
Food molecules go through chemical reactions that create energy that cells use to create ATP
Many reactions in our cells require energy
Cell Transport
Active Transport
Active Transport: Bulk Transport
Exocytosis
Allows a vesicle inside the cell to bind with the cell membrane and to release the substance
Endocytosis
Allows a cell to engulf a substance and bring it into the cell
Bulk Transport has 2 processes that move
Larger particles like a single celledorganism or debris across the cell membrane
Small amounts of fluid
Very large molecules
Like facilitated diffusion active transport involves proteins in the cell membrane
Substances are being transported from an area of low concentration to high concentration
Unlike facilitated diffusion active transport uses energy
Passive Transport: Osmosis
When concentration on both side of the membrane is the same more movement will occur
Water will move from an area with a higher concentration of water to an area of low concentration
Particles can not cross the membrane but water can
Osmosis: The diffusion of water across a semipermeable membrane
Passive Transport: Facilitated Diffusion
In facilitated diffusion articles are transported across the membrane by proteins
Particles still travel across the membrane is facilitated diffusion
Glucose is transported this way
2. A protein can bind to a protein, transport it across the membrane and release it inside the cell
Some of these particles include ions (charged particles), large molecules
1. A protein can provide a channel to hydrophilic particles
This happens in 2 ways
Some particles cannot pass through the cell membrane on their own
Passive Transport: Simple Diffusion
Does NOT require energy
When these substances cross the membrane it's called Simple Diffusion
Substances that can pass through (small molecules, small lipids)
The cell membrane allows some substances but not all. This is a semi permeable membrane
Macromolecule
Nucleic Acids
DNA is a double spiral 2 strands linked together.DNA stores genetic information
RNA (ribonucleic acid) is a single spiral, one strand linked together
Nucleic acids are a polymer made of monomers called nucleotides
Proteins
Amino acids are protein monomers
Amino acids link together using special bonds, peptide bonds
All have a central carbon bonded to 4 other atoms or groups
Jobs are to control what is going in and out of a cell
Build hair and finger nails
Carry oxygen in blood
Help blood to clot
Proteins have the most jobs in a cell of any other biological molecule
Lipids: Triglycerides
The structure of the fatty acids determine the properties of the triglyceride
Triglycerides are made of 2 long hydrocarbons called fatty acids bonded to glycerol, a 2 carbon molecule
Lipids: Phospholipids
Their unique structure is what makes them perfect to form the membranes of our cells
Similar to triglycerides but they have 2 fatty acids
Lipids: Steroids
Commercially produced steroids are used to treat asthma
Lipids that have 4 interconnected rings
An example is cholesterol a key part of animal cell membranes
Carbohydrates
Carbohydrates are composed of C,H, and 0 atoms
Disaccharides
2 monosaccharides bonded together
Table sugar is sucrose, this is a disaccharide
Monosaccharides
Clear and colorless as sugars Ex.Glucose,Fructose, Galactose
Used by cells for fast energy
The simplest carbohydrate used biologically
Monosaccharides (single sugars), Disaccharides (2 sugars), Trisaccharides (many sugars)
3 Main types
Essential water
Hydrophobic: Water fearing. Substances that do not dissolve in water
Hydrophilic: Substances that dissolve well in water
Polar molecule
What are Organelles?
They are like ''Little organs''
Small structures in a cell have specific functions. Similar to our organs in our bodies
Basic cell types
Ex. Bacteria
Unicellular
No nucleus
No or a few organelles
Prokaryotes
Has organelles
Unicellular or multicellular
Ex. Animals, plants, fingi, protists
Has a nucleus
Eukaryotes
