Science Final Study Guide

Three Types Of Lipids

Fats, Oils, Waxes

The primary function of Lipids

Storing Energy

Elements that compose Lipids

Carbon, Hydrogen, and Oxygen

The difference between the ratios in Carbohydrates and the ratios in Lipids

Carbohydrates have two hydrogens and one oxygen for every carbohydrate. Lipids have far fewer oxygens for way more carbons and hydrogens.

What are the energy storage differences between lipids, versus carbohydrates and proteins?

Lipids store far more energy than proteins or carbohydrates. A gram of lipids stores 10 calories. A gram of protein and a gram of carbohydrate both store 4 calories. That’s less than half of what a lipid stores!

What’s the difference between fats and oils?

Fats are solid at room temperature. Oils are liquid at room temperature.

Where do fats and oils come from?

Fats generally come from animal sources. Oils generally come from plant sources.

The physical differences between fats and oils

Fats are made of saturated fatty acids, in which every carbon bonds to only one other carbon at a time. Oils are made up of unsaturated fats, in which there is at least one carbon double bond.

Basic structure of lipids

Lipids are made with one glycerol molecule and 1-3 fatty acid molecules

Monoglyceride =

A lipid with one glycerol and one fatty acid

Diglyceride =

A lipid with one glycerol and two fatty acids

Triglyceride =

A lipid with one glycerol and three fatty acids

How do hydrolysis and dehydration synthesis contribute to lipid formation?

A glycerol bonds to a fatty acid though dehydration synthesis. Hydrolysis just plays a role in lipid break down.

What two parts make up a fatty acid?

A carboxyl group and a hydrogen chain

Saturated Fatty Acid =

A fatty acid with no carbon double bonds. It would be an entirely straight fatty acid

Monounsaturated fatty acid =

A fatty acid with only one carbon double bond. It has only one bend

Polyunsaturated fatty acid =

A fatty acid with more than one carbon double bond! Considered even healthier than monounsaturated fatty acids

How many less hydrogens are there per carbon double-bond in a lipid?

There are two less hydrogens per carbon double-bond.

Why are saturated fats solid at room temperature and unsaturated fats liquid at room temperature?

Saturated fats are solid at room temperature because van Der Waals forces hold the flat fatty acids together. Unsaturated fats do not hold together well at room temperature because the van Der Waals forces are mitigated by the bend caused by the double bond.

What is a Trans Fat?

A trans fat is a fatty acid where an unsaturated carbon double bond, which was initially in “cis” position, the two bonds being on the same side, causing a bend, gets modified into a “trans” fat, with the two bond on opposite sides of the fatty acid chain, which would then still be essentially a straight line.

What is the process of hydrogenation?

Hydrogenation is where unsaturated oils are cooked under a lot of pressure, and hydrogens are added to the mix, with the intent of converting the liquid lipids into solid fats.

How does partial hydrogenation lead to trans fats?

Sometimes, instead of breaking all the carbon double bonds, the process of hydrogenation just causes one of the two double bonds to switch sides. This give the fat the solidity of a saturated fat, but really, it is a trans fat.

Hydrogenated oils were evented because

People thought it would be healthier than saturated fats from animals sources, which were known to have cholesterol. If they could take the plant fats and make them more solid and delicious in order to make products like cakes, they would be getting tasty stuff that lasts longer than animal products and (theoretically) healthier too!

Margerine was evented because…

Healthier butter substitute to make people “healthier” - eat less cholesterol. Artificial color and flavoring added to make it more marketable.

How do unsaturated fats, saturated fats, and trans fats compare health wise?

Unsaturated fats lower bad cholesterol and rase good cholesterol. Saturated fats raise bad cholesterol and do nothing to the good. Trans fats are known to be hard to digest and lead to heart disease - they raise bad cholesterol and lower good cholesterol. Trans fats are all around bad. They are even thought to cause cancer.

What do phospholipids do?

Phospholipids form phospholipid bilayers in water and are a major component of cell membranes.

What are the components of a phospholipid?

It has a hydrophilic, charged head made up of a positively charged choline and a negatively charged phosphate group and a hydrophobic tail made up of a lipid. It has a glycerol connecting to a hydrophobic head and two fatty acids.

Hydrophilic =

Attracted to water

Hydrophobic =

Repelled by water

Why do phospholipids form phospholipid bilayers?

Since the heads of phospholipids are hydrophilic, they are attracted to water. The tails on the other hand, are repelled by water. So, if two rows of phospholipids are next to each other, the tails will face each other, whereas the head will face the water on either side. In the middle of the two rows, which the hydrophobic tails face, there will be no water. This creates a barrier that water cannot go through.

What are the parts of a soap molecule?

It is made up of a fatty acid and a charged salt.

How do soaps work?

The salt of the soap is attracted to H2O and the fatty acid is attracted to oils, which is often the dirt. So soap forms around the oils, (with some agitation) while its hydrophilic salt faces the water, encasing the dirt and making it able to be washed away with water.

Soap Lab Synopsis

Soap surrounded lipid oil when stirred because hydrophobic fatty acid attracted to oils. Salt head is attracted to water, so soap forms micelles (bubbles) around the oil and sinks to the bottom at first, because it is more dense than the water. Some soap bubbles floated back up, because (according to my research) the soap bubbles were negatively charged and repelled each other.

Acid Lab Synopsis

The milk protein, casein, denaturized once it reached a pH lower than 4.5 because the bond between the string of amino acid’s r-groups connected to each other got disrupted by additional hydrogen ions in the acidic solution. The R-Groups of the amino acids bonded to the hydrogen instead of each other, so they broke apart back into their primary structure of a long chain of amino acids. This chain then formed more solid milk than when it was in it’s normal, liquid form due to Van der Waals forces.

Protein name source

“Proteios” = Primary

The primary function of proteins

They are mainly a structural molecule.

Proteins are made of….

Carbon, Hydrogen, Oxygen, and Nitrogen

Examples of Proteins

Insulin, hair, skin, muscles, bone, white blood cells, red blood cells, and cartilage

Monopeptides and Animo acids…

Are the same thing.

One amino acid is a

Monopeptide

Two amino acids together is a

Dipeptide

Three or more amino acids together is a

Polypeptide chain.

What does dehydration synthesis and hydrolysis have to do with the construction/destruction of polypeptide chains?

Dehydration synthesis is needed to bind amino acids together. For digestive purposes, hydrolysis is then needed to break the polypeptide chain apart into individual amino acids.

The basic structure of amino acids

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What is an R-Group?

An R-Group is a different set of compounds for each of the 20 different amino acids. It’s what makes each amino acid unique from the other 19 types.

Part all aminos have in common

Each have their own R-Group (different for each one, but they all also have a carboxyl group, a hydrogen, and an amino group __bonded to a central carbon__

How do R-Groups play a role in the formation of proteins?

After a polypeptide chain is created by ribosomes in the cell, the R-Groups of the different amino acids in the chain interact with each other and surrounding water to fold and coil into unique shapes to create different types of proteins.

Out of the 20 amino acids, why are 8 called essential?

Eight amino acids are called essential, because those eight are the ones we have to eat as humans, because our bodies need them but can’t produce them on our own.

How are proteins made?

mRNA is fed into ribosomes to begin creating polypeptide chains by having specific amino acids placed in a sequence. The amino acids in that chain then begin to either fold into α helixs or β pleated sheets. That creates a subunit of a protein, once it is done folding. Multiple subunits come together to form a functional protein.

Primary Structure of a Protein

A polypeptide chain, fresh out of a ribosome, right before it starts folding.

Secondary Structure of a Protein

A polypeptide chain once it’s R-Groups start to interact with one another and fold

Tertiary Structure of a Protein

A subunit of what will become a protein that has finished folding

Quaternary Structure of a Protein

A finished protein, made up of multiple subunits.

Denaturation (Look at folder on lab)

Proteins unfolding

What would happen is an incorrect amino acid is put into a polypeptide chain?

The protein would wind up different! The R-Groups would interact differently with the incorrect amino acid’s R-Group, which would create a different looking subunit, which would contribute to a protein that functions differently!

What are the two types of nucleic acids?

DNA and RNA

What does DNA stand for?

__Deoxy__ribonucleic acid

What does RNA stand for?

Ribonucleic acid

What are the three parts of DNA and RNA nucleotides?

The include a phosphate group (PO4), a sugar, and one of four possible nitrogen bases.

What are the differences between a DNA nucleotide and a RNA nucleotide?

A DNA nucleotide has a five-carbon sugar ribose without an oxygen, whereas a RNA nucleotide has a ribose sugar, oxygen and all. Another difference is that the four possible nitrogen bases for DNA are adenine, thymine, cytosine, and guanine, but in RNA thymine is replaced with uracil.

What is the difference between DNA polynucleotides and RNA polynucleotides?

DNA polynucleotides form a double helix, while RNA polynucleotides form a single chain.

What do DNA polynucleotides do?

They store all the information required for our bodies as well as all the information on how to carry out life-sustaining processes.

What is the function of RNA polynucleotides?

RNA copies specific genes or “instructions” from DNA and transports them to ribosomes so they can make the proteins needed.

What nitrogen bases pair with each other?

Cytosine (C) pairs with guanine (G), and adenine (A) always pairs with thymine (T) in DNA and with uracil (U) in RNA.

The Genetic Code…

Is the sequence of nitrogen bases on DNA that comprises the entire set of instructions for how to make proteins to do functions so we can live. Each three nitrogen bases stand for a single amino acid, with there being points where there are three nitrogen bases that tell ribosomes to end the code there. The genetic code gets transcribed to RNA and translated to ribosomes in order to be made into proteins.

The Central Dogma of information flow =

DNA **replicates** itself before cell division. DNA **transcribes** (makes copies) of specific genes in the form of RNA. The RNA gets **translated** (read) to ribosomes to give them instructions to create functioning proteins.

What does the Central Dogma of Information flow have to Dehydration Synthesis?

Dehydration synthesis is used to bond the amino acids together once the ribosome receives the instructions in the mRNA, which were transcripted from the DNA.

How are cells classified? What are the three domains?

All cells are in Archaea, Bacteria, and Eukaryote.

What are the three parts of the Cell Theory?

1. All living organisms are composed of one or more cells. - Schleiden and Schwann
2. Cells are the basic unit of structure and organization of all organisms. - Schleiden and Schwann
3. Cells arise from previously existing cells, with cells passing copies of their genetic material on to their daughter cells. -Virchow in the 1850s

Why do cells have to be small?

Cells have to be small because the larger an object gets, the less surface area it has comparatively to its volume. The surface area of a cell is the cell membrane, which needs to constantly take in resources and expel waste. If it isn’t big enough relative to the cell to care for all of the cell’s needs, the cell dies.

What is the difference between prokaryotes and eukaryotes?

Prokaryotes have no membrane bound structures; eukaryotes have membrane bound structures. Prokaryotes are far smaller than eukaryotes. Prokaryotes are generally just single-celled organisms, whereas eukaryotic living things are generally multi-cellular organisms.

What do plant cells have that animal cells do not have?

1. Chloroplasts
2. Cell walls
3. Central vacuole

What is the endosymbiotic theory and what are the three pieces of evidence for it?

Endosymbiotic theory states that larger prokaryotes ate smaller prokaryotes and the smaller prokaryotes lived inside the larger ones, eventually evolving so that they became a part of the offspring of the larger prokaryotes. This theory applies to mitochondrias and chloroplasts. Three pieces of evidence are:


1. Mitochondria and chloroplasts are of similar size to prokaryotes.
2. Mitochondria and chloroplasts can reproduce semi-autonomously; they have ribosomes to make their own proteins as well as their own genetic material.
3. Mitochondria and chloroplasts have a double membrane surrounding them, which suggest that they (wit their own membranes) may have been engulfed by what was once an outer cell membrane of the larger prokaryote in a vesicle.

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What organelles make up the endomembrane system?

The Nucleus, the Endoplasmic Reticulum (+ Ribosomes), the Golgi Body, and the Cell Membrane are parts of the EMS which relate to the secretion of proteins, but other parts that do other things are lysosomes and vacuoles.

Step one of the EMS’s process of secreting substances

The RNA makes a copy of the instructions (DNA) for the protein that is eventually going to be secreted (Transcription). Then the RNA leaves the nucleus membrane.

Step Two of the EMS’s process of secreting substances

The RNA binds with a ribosome on the E.R. (specifically the Rough E.R.) The ribosome “reads” the instructions from the RNA and joins amino acids together to form a polypeptide chain (Translation).

Step Three in the EMS’s process of Secreting Substances

As the polypeptide chain grows, it is inserted into the inside (call the lumen) of the E.R. Different polypeptide chains can be assembled inside the E.R. to make functional proteins. These proteins can be stored until the cell is ready (or signaled) to secrete them. When ready, the proteins will travel from the E.R. to the Golgi body inside a vesical, which is a membrane container.

Step Four in the EMS’s process of Secreting Substances

The vessical containing the proteins fuses with the Golgi Body. The Protein has carbohydrates added to it as it passes through the flattened membranes of the Golgi Body. It has been “packaged for shipping”, so to speak. The “packaged” protein leaves the Golgi Body in another membrane vessical.

Step Five in the EMS’s process of Secreting Substances

The vesical from the Golgi Body fuses with the cell membrane. Protein “spills” out of the cell (into the blood stream).

What is the relationship between the Central Dogma of Information flow and the Endomembrane system?

The Central Dogma of Information, which states how proteins are made from the instructions in the DNA, occurs through the Endomembrane system. Understanding the Endomembrane system involves knowing the central dogma of how transcription and translation occur, and then learning in what specific locations does this occur and what must be done before the created protein is secreted.

What is selective permeability? Why would it be important?

Selective permeability is the ability to let some substances pass through while keeping other out. This is an important trait for the cell membrane to have, as intaking needed resources and expelling and keeping out waste are crucial to maintaining homeostasis within a cell.

What are the four key functions of the cell membrane?

1. Separates cell from surrounding environment
2. Controls movement of substances into/out of the cell
3. Maintains different internal conditions than the outside (homeostasis)
4. Maintains constant conditions inside the cell (also homeostasis)

What are the two major parts of the cell membrane?

A phospholipid bilayer and membrane bound proteins.

What are the four main functions of membrane proteins?

Transport, Cell Recognition, Reception, and Cell Connection

What is polar and what is not polar in a phospholipid?

The head, a phosphate group, is polar. The tail, fatty acids, are not polar.

What is passive transport?

Passive transport is any type of transport into or out of a cell that does not require a cell to use energy, because they are diffusing down the concentration gradient.

What is the difference between facilitated and simple diffusion?

Facilitated diffusion is a type of passive transport that occurs through transport proteins, still going down the concentration gradient. Simple diffusion is diffusion that does not expend energy that goes directly through the phospholipid bilayer.

Active Transport is….

Substances moved from low concentration to high concentration in a way that expends energy. It is endothermic

What is endocytosis?

Large engulfing of substances into the cell. Phagocytosis = engulfing solids. Pinocytosis = engulfing liquids. Engulfs by intaking objects by surrounding them with vesicles.

What is Exocytosis?

The large secretion of substances from the cell. Also uses vesicles.

Bulk Transport, which is endocytosis and exocytosis, is a type of

Active Transport.

What is tonicity?

The amount of water outside of cell (inversely proportional to the amount of dissolved substances outside of a cell)

What is a hypotonic solution?

A solution where there is more water and less dissolved substances than there is in the cell. Water then flows into the cell, and causes it to swell. Dissolved substances go out.

What is a hypertonic solution?

A solution where there is less water and more dissolved substances than there is inside the cell. Water flows out of the cell, drying it up, while dissolved substances flow into the cell.

What is an isotonic solution?

There is equal amounts of water and solute outside of the cell.

What does it mean that organelles do not work alone?

Organelles do not work alone in that they work together like organs do to perform complex functions.

What is the main function of the endomembrane system?

It’s major function is to produce proteins and substances that will be secreted by our cells.

* copy organelles in chart 7.1

A Mitochondria is

The organelle is where glucose is broken down to release energy for the cell. It had a high amount of enzymes. It is found in almost all Eukaryotic cell.

A Chloroplast is

An organelle where photosynthesis occurs. It converts sunlight energy into glucose energy.