Chapter 1.3.2 Macromolecules Flashcards by Michael Zhang

What are the four main classes of important molecules

Carbohydrates
Lipids
Proteins
Nucleic acids

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What are macromolecules considered to be

Polymers

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What is a polymer

Long molecule consisting of building blocks linked by covalent bonds

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What are polymers built from

Monomers

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What is a monomer

Repeating units that are the building blocks

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Why are enzymes helpful for cells

Because they help making/destroying polymers by increasing the rate of reaction (most enzymes are proteins)

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What does the dehydration reaction consist of

Consists of synthesizing a polymer by removing a water molecule to covalently bond 2 molecules

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What does the hydrolysis reaction consist of

Consists of breaking down a polymer by adding a water molecule (reverse of dehydration)

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Which of the four main important molecules is NOT a macromolecule

Lipids, too small to form polymers

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What are carbohydrates

Sugars or polymers of sugars

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Name the simplest form of carbohydrates

Monosaccharides (is a monomer)

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What is a polysaccharide

Polymers composed of many sugars

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What is most common monosaccharide

Glucose (C6H12O6)

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What is the molecular composition of sugars

They’re made of at least 3 C with O and H and they’re polar

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How do we name carbon chains based on their length (assuming they all end with -ose)

By using numeral prefixes such as hex for 6, tri for 3 and pent for 5 (if it ends by -ose, it’s most likely a sugar)

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By what reaction do two monosaccharides form one disaccharide and what name do we use for their link

Dehydration reaction
Glycosidic linkage

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What are the two monosaccharides that compose Maltose

Glucose + Glucose

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What are the two monosaccharides that compose Sucrose

Glucose + Fructose

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What are the two monosaccharides that compose Lactose

Glucose + Galactose

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Name the two uses of carbs

Storage polysaccharides
Structural polysaccharides

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The function and shapes of the polysaccharides depend on 2 things

Their sugar monomers
The positions of their glycosidic linkage

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Is starch a storage or structural polysaccharide

Storage

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Is Cellulose a storage or structural polysaccharide

Structural

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What are the 2 forms of starch stored in plastids

Amylose (simplest, unbranched)
Amylopectin (branched)

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What do animals store carbohydrates as, in their liver or muscle cells

As glycogen (branched ++)

What makes cellulose a structural polysaccharide

1. Tough 2. Polymer of glucose (like starch) with straight and linear linkages

What are the two different ring structures for glucose and what differentiates them

1. Alpha (-OH group of first C is below plane of ring) 2. Beta (-OH group of first C is above plane of ring)

In what form of ring structure does starch presents itself in

All in alpha form

In what form of ring structure does cellulose presents itself in

All in beta form

What differs between the linkages and structures of starch and cellulose

- Structure and linkages of starch are helical - Structure and linkages of cellulose are straight and never branched

Name the parallel cellulose strands held together by H bonds in plant cells

Microfibrils

An enzyme that can hydrolyze alpha can also hydrolyze beta linkages

False

What are the cell walls of fungi made of, what structural polysaccharide

Cithin

Are lipids a group of hydro phobic or philic molecules

Hydrophobic

Why are lipids hydrophobic

- Mostly hydrocarbon bonds, not polar - Few polar bonds with O

What are the 3 most important lipids

1. Fats 2. Phospholipids 3. Steroids

By what reaction are large molecules of lipids assembled from smaller molecules

Dehydration reaction

What is a fat composed of

1 glycerol and 3 fatty acids

What characterize a saturated fat

- No double bonds - As many H as possible

What characterize an unsaturated fat

- One or more double bonds

Explain why saturated fats can stay solid at room temperature

Because the flexibility from their single bonds let them pack together tightly

Explain why unsaturated fats are often liquid at room temperature

Because their double bonds prevents them from packing together tightly enough to stay solid

What is the main function of fat

Energy storage (a gram of fat store more than 2x the energy of a gram of polysaccharide like starch)

How does fat help animals other that being a source of energy

- Can cushion vital organs - Helps insulate to keep warmer body temperature

What part of the cell do phospholipids make up

The cell membrane

How can the phospholipids self assemble into a bi-layer in water

Because one side is hydrophilic (the head) and the other is hydrophobic (tails)

What are steroids characterized by

A carbon skeleton consisting of 4 fused rings

Rearranging cholesterol can result in other steroids

True

Name examples of steroids we saw in class

- Cholesterol - Vertebrate sex hormones

Name the 4 functions or proteins

1. **Enzymatic proteins** : selective acceleration of chemical reactions 2. **Defensive proteins** : protection against disease 3. **Storage proteins** : storage of amino acids 4. **Transport proteins** : transport of substances

Name the 4 different types of proteins

1. **Hormonal proteins** : coordination of an organism's activities 2. **Receptor proteins** : response of cell to chemical stimuli 3. **Contractile and motor proteins** : movement 4. **Structural proteins** : support

What are the monomers of proteins called

Amino acids

What are the polymers of proteins called

Peptides or polypeptides

Define protein

Biologically functional molecule made up of one or more polypeptides

What is an amino acid composed of

- NH3+ group - COO- group - H atom - R group (variant group)

What does the side chain (variable group R) does in an amino acid

Determines the characteristics of the the amino acid

What makes certain amino acids hydrophobic

Their side chains/bonds do not contain oxygen making them nonpolar

What does having O in a side bond of an amino acid do

It charges it, making it polar and hydrophilic

What is a peptide bond

Resulting covalent bond formed by the linkage of two amino acid polymers

By what type of reaction do amino acid polymers link together to form chains

Dehydration reaction

How can you recognize polypeptides

By their N terminus and C terminus

What do nucleic acids do

Store, transmit and help express hereditary information

What determines a polypeptide's amino acid sequence

Programmed by a gene

What are the monomers of nucleic acids called

Nucleotides

What are the 2 types of nucleic acids

- DNA (deoxyribonucleic acid) - RNA (ribonucleic acid)

If the DNA acts like a blueprint and does not carry out the activities, what does

Proteins

What are the 3 steps of gene expression

1. Synthesis of mRNA in the nucleus 2. Movement of mRNA into cytoplasm via nuclear pore 3. Synthesis of protein using information carried on mRNA (occurs at the ribosome)

What are the 3 parts that compose a nucleotide

1. Nitrogenous base 2. Pentose sugar 3. One or more phosphate groups

What are the 2 types of nitrogenous bases

Pyrimidines and purines

What are the nitrogenous bases in pyrimidines

Cytosine, Thymine and Uracil (in RNA)

What are the nitrogenous bases in purines

Adenine and Guanine

What nitrogenous base is exclusive to DNA

Thymine

What nitrogenous base is exclusive to RNA

Uracil

What are the components of the nucleoside

Sugar + nitrogenous base

What is the difference between the two sugar Deoxyribose (in DNA) and Ribose (in RNA)

Deoxyribose lacks an atom of O

What type of linkage join nucleotides

Phosphodiester linkages

Are nitrogenous bases part of the backbone

What is the structure of DNA composed of

2 polynucleotides that forms a double helix

What are the 2 DNA strands held together by

H bonds

In DNA what does A and G pairs with

T and C

What do we call the strands of DNA when we know the sequence of one strand because of the other one

That they are complementary

The amounts of the A and T(A and U in RNA) and C and G pairs are equivalent

True

RNA exists as single strands

True

What are the 3 kinds of cellular work

1. Chemical : pushing endergonic/anabolic reaction (requires energy) 2. Transport : pumping substances across membranes 3. Mechanical : muscle contraction, movement of chromosomes during cellular reproduction

What is ATP (adenosine triphosphate)

Source of energy that powers cellular work Eg. making RNA

What does ATP contain (3)

- Ribose - Nitrogenous base (Adenine) - Triphosphate (chain of 3 phosphate groups)

Why does ATP releases more energy than most other molecules

- Because all 3 phosphate groups are negatively charged so they repel each other - Triphosphate tail acts like a compressed spring ready to be released

What is the ATP cycle

The process of coupling exergonic processes to endergonic ones

How do plants make ATP

By using light energy