AP Biology Exam Study Guide

What is a hydrogen bond?

A bond where a hydrogen atom bonds to another electronegative atom.

Where can you find a hydrogen bond in water?

Between a positively charged hydrogen atom and negatively charged oxygen atom of another chemical.

Where is the hydrogen bond found in DNA?

Hydrogen bond is found between the nitrogenous base pairs (ACTG).

How many hydrogen bonds are in between each nitrogenous base pair?

2 in between AT and 3 in between CG.

What is the structure of a amino acid?

A central carbon atom attached to an amino group, a carbouxly group, a hydrogen atom, and a “R group”

What are the three types of R groups and what is there polarity?

nonpolar (hydrophobic, polar (hydrophlic), and charged (either acidic or basic.

Why is water considered a polar molecule?

Enequal sharing of electrons between the atoms and the unsymmetrical shape of the molecule.

How can water move up a capillary tube to move from the roots to the leaves?

As water evaporates from the leaf, hydrogen bonds cause the water molecules leaving the veins to tug on the molecules further down-pulling the water up through the plant. This is made possible by cohesion as the water attempts to stick together, and also adhesion as adhesion of water to cell walls by hodrgen bonds helps counter the downward pull of gravity as water moves up the capillary tube.

What are the three properties of water and how does hydrogen bonds allow each of these?

High surface tensions: The strong hydrogen bonds create a cohesive layer on the surface of water, allowing it to resist external force. High specific heat: Hydrogen bonds absorb a lot of energy before breaking, moderating temperature changes. Solvent properties: The polar nature of water allows it to dissolve various substances, facilitating chemical reactions.

Using water properties, explain how a water strider can walk on water?

The water strider can walk on water due to high surface tension created by hydrogen bonds between water molecules. This cohesive property allows the insect to distribute its weight across the surface without breaking the surface.

What are the four macromolecules?

Carbohydrates, lipids, nucleic acids, and proteins.

What are the elements found in carbohydrates?

Carbon (C), hydrogen (H), and oxygen (O).

What are the three functions of carbohydrates in living organisms?

Energy source, structural support, and building blocks.

What are the elements found in proteins?

Carbon (C), Hydrogen (H), Oxygen (O), Nitrogen (N), and sometimes sulfur (S).

What are the functional groups found in all amino acids?

Amino group, carboxyl group, alpha carbon, and side chain.

What are three functions of proteins in living organisms?

Providing structure, regulating body processes, and balancing fluids.

What are the elements found in nucleic acids?

Carbon (C), hydrogen (H), oxygen (O), nitrogen (N), and phosphorus (P).

What are parts found in all nucleotides?

A nitrogenous base, a phosphate group, and a sugar molecule.

What are three functions of nucleic acids in living organisms?

carrying genetic information, facilitating protein synthesis and transmitting genetic information.

What are the elements found in a lipid?

Carbon (C), hydrogen (H), oxygen (O), and sometimes phosphorus (P).

How are the three different types of lipid different?

They differ in structure, function, and saturation levels. The three main types are triglycerides, phospholipids, and steroids. Triglycerides store energy, phospholipids form cell membranes, and steriods are components of cell membranes.

What are 3 functions of lipids in living organisms?

energy storage, cell membrane structure, signaling molecules.

What macromolecule(s) contain nitrogen?

Proteins and nucleic acids

What macromolecule(s) contain phosphorus?

Nucleic acids.

What macromolecule(s) contain sulfur?

proteins, and certain amino acids.

How does the R group affect the folding of the protein?

The R-groups stick out on the side of a polypeptide, freeing them to chemically interact with one another. Side chain interactions form each protein’s specific structure, a structure uniquely capable of performing that protein’s cellular function.

What is dehydration?

Dehydration is a chemical reaction that involves the removal of water molecules during the formation of a bond between two molecules, commonly seen in the synthesis of polymers from monomers.

What is an example of dehydration?

Someone forget to drink enough water while exercising on a hot day, leading to a dry mouth, dizziness, and fatigue, especially if the exercise is intense and prolonged.

What is hydrolysis?

Hydrolysis is a chemical reaction that involves the addition of water molecules to break bonds between molecules, typically leading to the breakdown of polymers into monomers.

What is an example of hydrolysis?

The breakdown of sucrose, a disaccharide, into its component monosaccharides, glucose and fructose, by adding water, which is the process of breaking down compex carbohydrates into simpler forms.

What type of bond is found in carbohydrates?

Glycosidic bonds, covalent bonds that link monosaccharides together.

Where is the glycosidic bond found in carbohydrates

Between 2 monosaccharide units within a carbohydrate molecule.

What type of bond is found between protein monomers?

Covalent peptide bond.

Where is the covalent peptide bond located in protein monomers?

Between the carboxyl group of one amino acid and the amino group of the next amino acid.

What type of bonds is found between nucleic acid monomers?

Phosphodiester bond

Where is the phosphodiester bond located in the nucleic acid monomers?

Between the 5’ carbon of one sugar molecule in a nucleotide and the 3’ carbon of the adjacent sugar molecule.

What is the monomer of a carbohydrate?

A monosaccharide

What are the components of a monosaccharide?

Carbon, hydrogen, and oxygen atoms.

What is the monomer of a protein?

Amino acid

What is the component of amino acids?

A central carbon atom, an amino group, a carboxyl group, and a side chain.

What are the components of a phospholipid?

A glycerol backbone, two fatty acid tails, a phosphate group, a hydrophilic head, and hydrophobic tails.

What type of bond is found in starch?

Alpha-glycosidic bonds

What type of bond is found in cellulose?

4-glycosidic bonds

What bond can be broken by animal?

alpha-glycosidic bonds.

How does a saturated and unsaturated fatty acid differ?

saturated fatty acids lack double bonds between carbon atoms, while unsaturated fatty acids have at least one double bond, causing a bend in the molecule and affecting their physical properties.

How does the level of saturation affect the function of the lipid?

Saturated lipids tending to form solid, tightly packed structures.

Describe how a nonpolar to polar R group substitution changes the structure and function of a protein?

Polar R-groups are hydrophilic, preferring the surface, while nonpolar R-groups are hydrophobic, tending to cluster inside, disrupting these interactions, altering folding, and possibly impacting the protein's binding capabilities.

Describe how a cytosine to thymine substitution changes the structure and function of DNA

Alters the DNA sequence, potentially disrupting the normal structure and function of the resulting protein, depending on its location and the nature of the change.

Describe how a cytosine to guanine substitution changes the structure and function of the DNA?

Changing the intended base pairing, which can lead to changes in protein synthesis or even lead to non-functional proteins.

Describe how a deoxyribose to ribose change the structure and function of a nucleic acid?

Altering their stability and reactivity.

Describe the structure of the nucleic acid polymer?

formed by linking nucleotide monomers, each composed of a nitrogenous base, a pentose sugar (deoxyribose in DNA, ribose in RNA), and a phosphate group, via phosphodiester bonds.

What are the ends called of the nucleic acid polymer and what is found at each end?

5' (five-prime) and 3' (three-prime) ends, and they are characterized by a phosphate group at the 5' end and a hydroxyl group at the 3' end.

Which nucleic acid polymer end is the location of the growing nucleic acid strand?

The 3' (three prime) end of a nucleic acid polymer is where the growing strand is synthesized,

What are the complementary base pairings found in nucleic acids?

adenine (A) with thymine (T), and guanine (G) with cytosine (C).

Identify the number of hydrogen bonds found between these two nitrogenous bases?

Adenine (A) and Thymine (T) form two hydrogen bonds, while Guanine (G) and Cytosine (C) form three hydrogen bonds.

What are the ends of a protein called and what is found at each end?

the N-terminus (amino terminus) and the C-terminus (carboxyl terminus)

Which protein end is the location of the growing polypeptide strand?

C-terminus (Carboxyl terminus)

Describe the structure of a carbohydrate polymer?

large molecules built from repeating units of monosaccharides (simple sugars) linked by glycosidic bonds, forming chains that can be linear or branched.

What are the components of a fat molecule?

glycerol and three fatty acids.

What are the components of a phospholipid?

a hydrophilic (water-attracting) head and two hydrophobic (water-repelling) tails, typically connected by a glycerol molecule.

Describe the structure of a steroid?

seventeen carbon atoms, bonded in four fused rings:

What are the three components of a DNA or RNA molecule?

a nitrogenous base, a pentose sugar (deoxyribose in DNA, ribose in RNA), and a phosphate group.

What is the structure and function of the ribosome?

Ribosomes consist of RNA and proteins and they help with synthesizing proteins. There is a large and small subunit.

How does the structure of the ribosome aid in the function?

The structure of the ribosome allows proteins to be made inside or outside the cell.

What are the three types of RNA involved in the structure or function of the ribosome?

messenger (mRNA) is transcribed from DNA and carries the message to cytoplasm where ribosomes translate it into a polypeptide

transfer (tRNA): carries a specific amino acid to the correct position on the ribosome using its anticodon to match to the codon on the mRNA.

ribosomal (rRNA): joins with proteins to make ribosomes where translation occurs to form a protein.

How does the ribosome demonstrate a common ancestry of all known life?

All life forms have ribosomes.

What is the structure and function of the rough ER?

The rough endoplasmic reticulum is a series of connected flattened sacs, part of a continuous membrane organelle within the cytoplasm of eukaryotic cells, that plays a central role in the transport of proteins made on its attached ribosomes.

How does the structure of the rough ER aid in the function?

It allows for the production, folding, quality control and dispatch of some proteins.

What is the structure and function of the smooth ER?

It is a network of membranes called cisternae. They are held together by the cytoskeleton. The function of the smooth ER is to help with synthesizing lipids, phospholipids as in the plasma membrane and steroids.

How does the structure of the smooth ER aid in the function?

Smooth ER is a network of membranes that separate the cell into compartments for metabolic processes. Smooth ER functions in the synthesis of lipids in most cells, the breakdown of toxins in liver cells, and storage and release of Ca++ in muscle cells. Keeping the enzymes or molecules needed for a specific chemical pathway together in a specific area is more efficient.

What is the relationship between the ribosome and the rough ER?

Ribosomes attach to the rough ER and insert the proteins being made into the rough ER for intracellular transport to Golgi for modification and export.

What is the structure and function of the Golgi?

The Golgi apparatus is a central intracellular membrane-bound organelle. Its key function is to traffic, process, and sort newly synthesized membrane and secretory proteins and lipids.

How does the structure of the Golgi aid in the function?

It packages proteins into vesicles so they can be transported in or out of the cell.

What is the structure and function of the mitochondria?

It is membrane bound organelle that consists of an outer and inner membrane that produces energy for the cell by breaking down carbohydrates and producing ATP.

How does the structure of the mitochondria aid in the function?

The inner membrane folds increase surface area which allows for a lot of ATP to be formed and quickly.

What is the structure and function of the lysosome?

It is a small membrane bound organelle that has an acidic interior. The purpose of the lysosome is to break down excess or worn-out cell parts. They can also aid in destroying invading viruses and bacteria.

How does the structure of the lysosome aid in the function?

The membrane surrounding the lysosome keeps proteolytic enzymes separated from the rest of the cell. Proton pumps in lysosomal membranes create acidic interior for digestion.

What is the structure of the vacuole?

A membrane-bound organelle that is generally small and circular in structure.

What is the function of the food vacuole?

It is used for storage of nutrients, water or waste.

What is the function of the central vacuole?

In plants it helps to maintain water balance.

What is the function of the contractile vacuole?

To maintain the constant osmotic pressure in the fluids of an organism by the control of water and salt concentrations in a well-balanced way so that the cell doesn't get ruptured due to cytolysis. (Osmoregulation)

What is the structure and function of a chloroplast?

Plant cell organelle that is oval-shaped and has an outer membrane and inner membrane folded into thylakoid sacs stacked into grana that converts light energy into chemical energy through the process of photosynthesis.

How does the structure of the chloroplast aid in the function?

Thylakoid sacs make compartments to create the H+ gradient needed for ATP production during the light dependent reactions.

How does the endoplasmic reticulum provide mechanical support?

It can help maintain cell shape by interacting with the cytoplasmic matrix

How does the endoplasmic reticulum aid in protein synthesis?

It has ribosomes on it to perform protein synthesis

How does the endoplasmic reticulum aid in intracellular transport?

it will transport materials through vesicles

How does the lysosome aid in intracellular digestion?

It will break down food using its enzymes.

How does the lysosome aid in recycling the cell’s organic materials?

It will breakdown old or broken down organelles using its hydrolytic enzymes.

How does the lysosome aid in apoptosis (programmed cell death)?

lysosomes can release enzymes called proteases into the cytosol that will start the cascade of apoptosis

How does the vacuole assist in storage of macromolecules?

provides a lot of space for storage of many types of macromolecules

How does the vacuole provide turgor pressure?

the vacuole will fill up with water that pushes on the cell membrane which then pushes on the cell wall causing turgor pressure

What is the structure of the inner membrane (cristae) of the mitochondria?

Highly folded membranes

How does that contribute to the function of the inner membrane (cristae) of the mitochondria?

highly folded membranes allow for more surface area to complete the oxidative phosphorylation of cellular respiration

How is the chloroplast organized?

Many thylakoid membranes stacked to increase surface area for light reactions in photosynthesis.

What is embedded in the chloroplast and how does it aid in the function of the chloroplast?

Photosystems containing chlorophyll to absorb sunlight.

Where do the light-dependent and light-independent reactions take place?

Photosystems and ETC for the light independent reactions are located in the thylakoid membranes. Light independent reactions happen in the stroma.

How does the thylakoid aid in energy capturing?

Chlorophyll containing photosystems are located in thylakoid membranes.and numerous thylakoid sacs create more surface area to collect more light.

How does the thylakoid aid in energy storing?

Electron transport proteins are located in thylakoid membranes.and transport of H+ ions into the thylakoid space creates the H+ gradient needed for ATP production during the light dependent reactions.

Where does the citric acid cycle (Krebs cycle) in cellular respiration take place?

Matrix of mitochondria

Where does the electron transport chain in cellular respiration take place?

Proteins for ETC are located in cristae membranes.