Final Practice Questions

In a multicellular eukaryote such as yourself, there are many different kinds of cells with many different functions and shapes. What makes one cell so different from another?

They make different transcription factors and express different genes

If two elements that have a noticeable difference in electronegativity form a covalent bond together, which of the following will be true?

They will have unequal sharing of electron

Phospholipids are special because they are amphipathic - what does that mean?

This means that Phospholipids are both hydrophilic and hydrophobic. The head is hydrophilic and the tails are hydrophobic

What is the function of ribosomes in cells?

To make proteins

ATP is the most common "energy currency" in cells because it is really good at storing and releasing energy for chemical reactions. What is special about the structure of ATP that makes this true?

What's special about ATP is the links between thee phosphate bonds it can create. It is able to attach to other phosphates and from there which is where the energy is stored.

When does osmosis happen?

When solutes can't diffuse

Atoms are composed of a nucleus made from protons and neutrons surrounded by clouds of electrons. Those electrons are organized into layers called... what?

orbitals

In atoms electrons are distributed into shells within which they occur as pairs in domains called orbitals

shells, orbitals

If you are given the sequence of one strand of a DNA double helix as: 3'-AATCGTC-5' What is the correct second strand?

5'-TTAGCAG-3'

When ligand binds and activates a receptor, the intracellular signal is amplified by what mechanism?

A signal transduction cascade

If you were to observe that gut cells are using a Na+-Sucrose symport protein to bring the sugar sucrose into cells against it's concentration gradient, and Na+ concentrations are high outside the cell, what additional transport protein would you conclude must also be in gut cells.

A sodium ion pump

In addition to "uses energy," what other criterion can be used to recognize active transport?

Active transport can be recognized because it pushes something towards high concentration.

What are talking about when we discuss metabolism in this class?

All of the chemical reactions in an organism

Why are some elements chemically reactive and tend to combine with other elements to form molecules?

Because they have unpaired electros

Which one of the following will you always associate with catabolic reactions?

Breaking molecules down

Which of the following structures would be found in ALL cells?

DNA

As concisely as you can manage, define "diffusion."

Diffusion is movement from higher concentration to a lower concentration.

Entropy is a measure of...

Disorder

Briefly explain what holds molecules with ionic bonds together?

Electrons are moved to other atoms and particles with opposite charges attract each other.

Briefly explain the difference in initiation of transcription between prokaryotes and eukaryotes, focusing on how RNA polymerase interacts with the TATA box.

Eukaryotes require basal transcription factors, while prokaryotic RNA polymerase interacts directly with the TATA box.

There is often confusion about where in the cell we should find pyruvate, usually involving a debate between the cytoplasm and the matrix. Why should we not find pyruvate in the matrix?

Even though pyruvate is being transported in the mitochondria, it is being converted to acetyl-CoA as it goes. So we find pyruvate in the cytoplasm (where it is produced) and acetyl-CoA in the matrix.

What Big Idea is best represented by the following example: The Covid-19 virus is experiencing frequent changes to its DNA over time, creating variants that differ from the "original" as a result of these mutations.

Evolution

Oil glands secrete large quantities of triglycerides and other lipids from vesicles made by the Golgi onto the surface of your skin. What type of transport is being used?

Exocytosis

What very important molecule is the direct product of photosynthesis?

G3P (sugars, fats, acids)

Which of the following pathways occurs in the cytoplasm of the cell?

Glycolysis

Primary structure of polypeptides consists of series of amino acids covalently connected by peptide bonds. When we digest protein we must break those peptide bonds to separate the individual amino acids, what do we call the kind of reaction (in general) being used?

Hydrolosis

Where is chemical energy stored in molecules?

In bonds

What are two things that are required in living cells to make positive delta G reactions "go"?

In order to make Delta G reactions go, cells need reaction coupling and enzymes.

The Second Law of Thermodynamics says the universe is always... what?

Increasing in entropy

An important part of understanding how enzymes work is the concept of induced fit. Briefly describe what that means.

Induced fit is where a substrate binds to the active site and then the enzyme changes shape. Because of this reaction occurs and then the product leaves the active site.

Your cells need to be able to control just about every aspect of metabolism, much of which involves regulating enzyme activity using Allosteric effectors that bind to an enzyme at the allosteric site . ________ are molecules that prevent an enzyme from working by ________

Inhibitors, changing the shape of the active site

Proteins that insert into the hydrophobic part of the phospholipid bilayer are called:

Integral proteins

Why is the first half of glycolysis called the "investment phase" while the second half of glycolysis is called the "payout phase?"

It costs two ATP to get started, but eventually four ATP are made for a net gain of two ATP.

Which of the following properties would most reliably indicate something is a living organism?

It is made of cells

Which of the following is true for facilitated diffusion?

It requires transmembrane proteins

What do all enzymes do?

Lower activation energy

Let's stretch our brain muscles a bit! What happens to the rate of ATP synthesis if the pH of the thylakoid lumen decreases? Explain how you figured this out!

Lower pH equals more H+ ions, so more power to ATP synthase!

Based on your experience so far, which of the following would be considered an anabolic process?

Making an H+ ion gradient

During cellular respiration, the mitochondria converts malate (C4H6O5) into oxaloacetate (C4H4O5). Which of the following is true?

Malate has been oxidized

Name ONE organelle that was likely acquired by endosymbiosis?

Membrane bound organelles

What molecule is the final electron acceptor for the light reactions?

NADP+

Which of the following is definitely part of the endomembrane system?

Nuclear envelope

Which of the following will pass through a phospholipid bilayer freely without assistance from transport proteins?

Oxygen (O2)

What is the higher energy electron donor for the electron transport chain in the first half of the light reactions?

Photosystem II

Any atom will have a nucleus that has positive charge from _______ , surround by particles with negative charge called _______

Protons, electrons

In the light reactions, electrons power an electron transport chain to do what work?

Pump H+ ions

What enzyme unwinds the DNA during transcription?

RNA polymerase

What is the purpose of splitting of water (photolysis) in the light reactions? Note: there is only one correct answer for this one!

Resupplying electrons to PS2.

Hydrogen bonding between backbone amino and carbyl groups of amino acids in newly made polypeptides makes the polymer form helix and sheet shapes. What LEVEL of protein structure is this?

Secondary

What advantage does extensive compartmentalization give eukaryotes as compared to their prokaryotic ancestors?

Since eukaryotes are more complex, the extensive compartmentalization helps for smaller sections to be focused on. Since prokaryotics aren't as complex, this wouldn't benefit them as much.

Which of the following would describe a negative delta G reaction?

Spontaneus

In your own words, what does the First Law of Thermodynamics tell us about energy?

The First Law of Thermodynamics tells us that energy cannot be created, it is only transferred/converted from one form of energy to another.

How does the ribosome "know" what amino acid to to add next when building a polypeptide?

The correct tRNA hydrogen bonds to the next codon

During the transition step, pyruvate is converted to acetyl-CoA and one carbon dioxide is released. Where does the CO2 come from?

The decarboxylation of pyruvate

Which of the following statements would you expect to be true if you know that two atoms are joined by a non-polar covalent bond?

The elements are similar in electronegativity

What is the function of the promoter in gene expression?

The promoter recruits RNA polymerase to the gene

What property do all lipids have in common?

They are hydrophobic

What very import limitation is shared by both RNA polymerases and DNA polymerases?

They can only add nucleotides to the 3'-end

The goal of cellular respiration is to produce ATP using energy from oxidizing glucose using a series of coupled pathways. The first pathway is _______ which converts glucose to pyruvate, generating ______ . Pyruvate goes through the______ , which generates ______ , and provides the substrate for the ______ which completes the catabolism of glucose and generates

1. Glycolosis 2. 2 ATP + 2 NADH 3. Transition step 4. 2 NADH 5. Citric acid cycle 6. 2 ATP + 2 NADH + 2 FADH2

Which of the following solutions is isotonic relative to a solution of 1.0 M glucose?

1.0 M glucose + 1.0 M fructose

If a cell needs to perform an anabolic reaction that requires +12.1 kcal/mole of free energy to work, it will need to use how many ATP?

2

Just by looking at the formula for hydrogen sulfide (H2S) you can immediately tell the element sulfur must have _______ unpaired valence electrons

2

If you transcribe a DNA template strand that has the following sequence: 5'-AATCGCATATG-3' What will be the sequence on the RNA?

3'-UUAGCGUAUAC-5'

The element magnesium is a flammable metal while hydroxide is in corrosive drain cleaner - both are very dangerous. However, when these are put together to make the molecule magnesium hydroxide, we get "milk of magnesia" which is a medicine that makes your upset tummy feel better. 1) What Big Idea is this an example of? 2) Describe how this example fits the definition of that Big Idea.

big idea is emergent properties