Cellular Biology

Basic cell types

Prokaryotes

Eukaryotes

Has a nucleus

Ex. Animals, plants, fingi, protists

Unicellular or multicellular

Has organelles

No or a few organelles

No nucleus

Unicellular

Ex. Bacteria

What are Organelles?

They are like ''Little organs''

Small structures in a cell have specific functions. Similar to our organs in our bodies

Macromolecule

Essential water

Polar molecule

Hydrophilic: Substances that dissolve well in water

Hydrophobic: Water fearing. Substances that do not dissolve in water

Carbohydrates

Carbohydrates are composed of C,H, and 0 atoms

3 Main types

Monosaccharides (single sugars), Disaccharides (2 sugars), Trisaccharides (many sugars)

Monosaccharides

The simplest carbohydrate used biologically

Used by cells for fast energy

Clear and colorless as sugars Ex.Glucose,Fructose, Galactose

Disaccharides

2 monosaccharides bonded together

Table sugar is sucrose, this is a disaccharide

Lipids: Steroids

Lipids that have 4 interconnected rings

An example is cholesterol a key part of animal cell membranes

Commercially produced steroids are used to treat asthma

Lipids: Phospholipids

Similar to triglycerides but they have 2 fatty acids

Their unique structure is what makes them perfect to form the membranes of our cells

Lipids: Triglycerides

Triglycerides are made of 2 long hydrocarbons called fatty acids bonded to glycerol, a 2 carbon molecule

The structure of the fatty acids determine the properties of the triglyceride

Proteins

Proteins have the most jobs in a cell of any other biological molecule

Jobs are to control what is going in and out of a cell

Carry oxygen in blood

Help blood to clot

Build hair and finger nails

Amino acids are protein monomers

All have a central carbon bonded to 4 other atoms or groups

Amino acids link together using special bonds, peptide bonds

Nucleic Acids

Nucleic acids are a polymer made of monomers called nucleotides

RNA (ribonucleic acid) is a single spiral, one strand linked together

DNA is a double spiral 2 strands linked together.DNA stores genetic information

Cell Transport

Passive Transport: Simple Diffusion

The cell membrane allows some substances but not all. This is a semi permeable membrane

Substances that can pass through (small molecules, small lipids)

When these substances cross the membrane it's called Simple Diffusion

Does NOT require energy

Passive Transport: Facilitated Diffusion

Some particles cannot pass through the cell membrane on their own

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

Particles still travel across the membrane is facilitated diffusion

2. A protein can bind to a protein, transport it across the membrane and release it inside the cell

Glucose is transported this way

Does NOT require energy

In facilitated diffusion articles are transported across the membrane by proteins

Passive Transport: Osmosis

Osmosis: The diffusion of water across a semipermeable membrane

Particles can not cross the membrane but water can

Water will move from an area with a higher concentration of water to an area of low concentration

When concentration on both side of the membrane is the same more movement will occur

Does NOT require energy

Active Transport

Like facilitated diffusion active transport involves proteins in the cell membrane

Unlike facilitated diffusion active transport uses energy

Substances are being transported from an area of low concentration to high concentration

Active Transport: Bulk Transport

Bulk Transport has 2 processes that move

Very large molecules

Small amounts of fluid

Larger particles like a single celledorganism or debris across the cell membrane

Endocytosis

Allows a cell to engulf a substance and bring it into the cell

Exocytosis

Allows a vesicle inside the cell to bind with the cell membrane and to release the substance

Energy In The Cell

Many reactions in our cells require energy

Food molecules go through chemical reactions that create energy that cells use to create ATP

ATP (adenosine triphosphate)is the molecule cells use for energy

How Cells Use ATP

ATP is mucleotide made of adenosine and 3 phosphate groups

ATP goes through a chemical reaction that releases a burst of energy used by the cell

ADP creates adenosine diphosphate and free phosphate group

Cellular Aerobic Respiration

Step 1: Glycolysis takes place in the cytosol

This reaction is controlled by enzymes

Creates 2 pyruvate (3 carbon molecule) and 2 ATP molecules for every glucose

ATP created per glucose molecule =36

6 oxygen are consumed

6 carbon dioxide and 6 water produced

Step 2: Oxidative Respiration takes place in the mitochondria

The pyruvate molecules created in glycolysis enter the mitochondria

A series of reactions occur that involve oxygen

With 2 pyruvate from every glucose entering this stage 34 ATP are created at this stage

Other than ATP carbon dioxide and water are the products of this reaction

Photosynthesis

Plants make their own food using photosynthesis

Photosynthesis takes place in the chloroplasts

After creading glucose plant cells also go through cellular respiration

Plants still create more oxygen than they use

Fermentation: Anaerobic Respiration

Fermentation is one process that organisms can produce energy without oxygen

Alcoholic fermentation: Pyruvate is converted to ethanol and carbon dioxide

Lactic Acid Fermentation: Pyruvate forms lactic acid

This happens in human muscle cells

Produces fewer ATP per glucose molecule compared to cellular respiration

Cell Membrane

Cell membranes are like the security or bouncers of a cell. They control what gets in and and out

Made up of a phospholipids bilayer, but not only phospholipids

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

Cell Theory

All cells come from preexisting cells

All living things are composed of one or more cells

The cell is the main unit of structure and organiztion in organisms

Animal cells

Cytoplasm

Includes: Cytosol- Everything inside the membrane except the nucleus

Jelly like and mostly made of water

Organelles

Cytoskeleton: Protein fibers and tubes that help the cell maintain structure

Everything that surrounds the nucleus

Cell Membrane

Barrier that surrounds the cytosol of the cell

Regulates what enters and exits the cell

Made of phospholipid bilayer and proteins

Nucleus

Contains all the cell's genetic information in the of DNA

DNA is also replicated here

Regulates gene expression

Controls cell division (mitosis)

The nucleus is surrounded by a nucleur envelope

Contain chromatin (the building blocks of chromosomes

Inside the nucleus is the nucleolus

Ribosomes

Produced in the nucleolus

Builds proteins (protein synthesis) and amino acids

So small cannot be seen using a typical microscope

Free ribosomes float in the cytoplasm

Other ribosomes attach to the endoplasmic reticulum

Animal cells are multicellular meaning multiple cells work together to complete an organism

Many different types and they all look different Ex. Liver cells, Kidney cells, Stem cells, Blood cells, etc

Endoplasmic Reticulum (ER)

A netw

Connected to the nucleus

The inside of the ER is separate from the inside of the nucleus

2 different parts (smooth ER & rough ER)

Substances made in the ER are transported by vesicles (small containers made of membrane)

Vesicles form when a cell or organelle membrane is pinched off

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

Rough ER

Proteins made by the ribosomes collect in the rough ER

Appears rough when using an electron microscope

Golgi Body

A stack of containers or sacks

Each sac contains a different enzyme

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

Some products include hormones or enzymes

Vacuoles

Act as storage compartments

Stores macromolecules and water

Very large in plant cells (often only one 80% it's volume called a central vacuole

Smaller in animal cells (often more than one)

Lysosomes

Containers or sacs that contain enzymes

Rough ER makes the membranes and enzymes and the Golgi body makes them into lysosomes

Only in ANIMAL CELLS

Digest macromolecules (proteins, fats, etc)

Why Cells Need To Digest Macromolecules

To fight diseases lysosomes breakdown the macromolecules in bacteria killing it

After digesting the cell absorbs food particles. Lysosomes help break it down

Recycling cell components

Killing the cell. Simultaneous release of the contents of many lysosomes can kill a cell

Mitochondria

The powerhouse of the cell

Made of a smooth outer membrane and an inner membrane with many folds

Converts nutrients into energy sing a series of reactions called cellular respiration

The number of mitochondria differs, often there are hundred or thousands in cell

Plant Cells

Plant cells are multicellular

Plant cells have a few main differences from animal cells

They often have one big vacuole called the central vacuole

Has chloroplasts

Has cell walls

Chloroplasts

Only in plant cells

Plants use chloroplasts to make their own food using photosynthesis

Responsible for the green color of plants

Contains enzymes and other chemicals used in photosynthesis

Cell Wall

Only in PLANT CELLS!

Surrounds the cell membrane

Is strong and rigid

Helps give the plants structure and shape

Mostly made of cellulose (fibre)

What Is Life Made Of?

Atoms: Humans and all things are made up of a combination of 52 elements

Atoms are the smallest possible piece of an element other (Na, Mg, P, K)

Compounds: A pure substance made up of one or more elements combined chemically

Whats An Enzyme?

Cells need a way to help control the chemical reactions, that's where enzymes come in

A substance that controls the rate of a reaction is called a catalyst

Catalysts in living things are called enzymes

Enzymes are specialized proteins that help ensure biological reactions occur at the perfect rate for life

Importance Of Enzymes

Because enzymes are a part of most reactions in a body problems can occur if an enzyme is missing or depleted

Humans who are lactose intolerant are missing the enzyme lactase

Lactase helps break down lactose found in milk products

Without it the small intestine cannot digest lactose

People can take a tablet to extract lactae

How Do Enzymes Work?

All reactions that take place need energy to occur, activation energy

Enzymes lower the activation energy of the specific reaction it's made for

How it works: Enzymes bond to the reactant molecules, also called substrates

The place where a substrate connects is called the active site

This also helps weaken existing bonds making it easier for products bonds to form

This puts the substrates in the best position for the reaction to occur

Once the reaction has occurred the enzyme is ready to work again!

Factors Affecting Enzymes

Because enzymes are proteins they can be damaged, or denatured

Ex, PH, Temperature

Enzyme Inhibitors

What?

Enzyme inhibitors control the amount of a product being made

2 types of inhibitors (Non-competitive inhibitors & Competitive inhibiitors)

Non- competitive Inhibitors ( A molecule bonds to a different site that then changes the shape of the active site)

Competitive Inhibitors (A molecule other than the intended bonds to the active site)

The Bad

Sometimes inhibitors have a negative effect

If a chemical bonds to stop a vital reaction it is a hazard

An example of this is a carbon monoxide