Cell Biology - Chapter 2

// Of the  92  naturally occurring elements, 16 are known to be  important constituents of living systems. The important elements are

==**C, H, O, N, P, S**,== K, Ca, Na, Cl, Mg, Fe, Cu, I, Mo, Zn

// All molecules that contain carbon are called **______** (except for  CO2).  All other molecules are _________.

organic; inorganic

// Most biological  molecules have a core  made of carbon and  hydrogen.  Molecules  differ in structure and function, in part,  because of different

**functional groups**.

// The major classes of biological molecules that are important for all  living things are __**_____, ________, _________, ___________**__**.**

__**carbohydrates**__, __**lipids**__, __**proteins**__, and __**nucleic**__  __**acids**__**.**

/ Large biological molecules are called

**macromolecules**

/ Macromolecules are built by combining smaller  building blocks into _________.__ ____________ (large carbohydrates) are polymers of  monosaccharides.

polymers; polysaccharides

/ Fats are built from _______ and ______.

fatty acids; glycerol.

/ Proteins are polypeptides - polymers of ___________.

amino acids

/ Nucleic acids are polymers of __________.

nucleotides

// **Carbohydrates**  - compounds made of  C, H, and O in a ratio of __________

1:2:1

// T/F: A __**c**__alorie is the amount of heat required to raise 1 g of water 1°C.

TRUE

// T/F: A kilocalorie is the amount of heat required to raise 1 kilogram of  water 1°C or 1 gram of water 1000°C.

TRUE

// T/F: A __C__alorie is a dietary unit of energy equal to a kilo__c__alorie. 

TRUE

// T/F: One gram of sugar has 4.1 Calories and 4.1 kilocalories.

TRUE

/ The simplest class of carbohydrates are __________.

\- simple  sugars  -  All have ==3 to 6 carbons==

monosaccharides

/ T/F: Simple sugars exist in different forms and can be drawn in different ways.

TRUE

/ The six carbon sugars all have the same chemical formula: C6H12O6 . They differ in the placement of functional groups ==C=O and -OH==

C6H12O6

/ _______ have the same chemical formula. 

_________.differ in the arrangement of a functional group at a single carbon.

Isomers; Stereoisomers

/ Monosaccharides are the building blocks of more ___________.

complex carbohydrates

// _________ are a  combination of two  monosaccharides.

Disaccharide

// Disaccharides are formed by __**dehydration synthesis**__ or a

_______________.__

condensation reaction

// Many of the larger  biological molecules are  built by combining smaller  molecules (building  blocks) through ______________ reactions.

dehydration synthesis  

// Many of the larger  biological molecules are  built by combining smaller  molecules (building  blocks) through  __**dehydration synthesis**__  reactions and the same molecules  can be broken apart into their component  building blocks by ____________ reactions.

hydrolysis

**// ___________** are **_________** of monosaccharides.  Polymers  are long chain molecules with repeating subunits.

Polysaccharides; polymers

// Starches are  polymers of glucose. Starches are used for __________. Each glucose  molecule is an  energy rich  molecule.

energy storage

/

* _______ is an ==unbranched chain== and is produced by plants.  
* _________ is ==branched== and also produced by plants.
* ________ is ==highly branched== and produced by animals.

Amylose; Amylopectin; Glycogen

/

* ______ is a  polymer of ==a-glucose== and  readily  digestible
* _______ is a  polymer of ==b-glucose== and  indigestible

Starch; Cellulose

/ Cellulose is a **__________** polysaccharide and used for the  construction of cell walls in plants.

structural

/ T/F: Another important **structural** polysaccharide is chitin.

TRUE

/ T/F: Even though chitin ==does== strictly follow the 1C : 2H : 1O rule for  carbohydrates it is still classified as a  **structural** polysaccharide.

FALSE

// The major classes of lipids are _______, __________, ________, __________ (or sterols).

fatty acids, neutral fats,  phospholipids, steroids

/Lipids have many functions including ____________, ____________, ____________, and ___________ (substances produced in one part of the body that  have effects on other parts of the body).

i. energy storage

ii. cell  membrane structure

iii. vitamins (biochemical helpers)

iv. hormones

/ **________** - a chemically diverse class of organic molecules that are  grouped together because they are all largely **________.**

Lipids; nonpolar

// **Fatty acids** come in two varieties _________ and ____________.

saturated and unsaturated.

/ T/F: Saturated fatty acids have ==no C=C bonds== - all carbons in the  chain are bonded to as many hydrogens as possible.

TRUE

/ T/F: Unsaturated fatty acids ==have some C=C== bonds in the chain - the  carbon chain is not completely saturated with hydrogens.

TRUE

//Fatty acids are a component of two other classes of lipids - **neutral fats** and **phospholipids**.

Neutral fats are molecules composed of

glycerol (a sugar alcohol)  and 1, 2, or 3 fatty acids

/ Neutral fats are used for long-term **_________.**

**energy storage**

Neutral fats are called

* __**_________**__ if their fatty acid chains are saturated (pack tightly)
* __**____________**__ if one or more chains  are unsaturated fatty acid (liquid).

saturated fats; unsaturated fats

/ **___________**  - **structural lipids**  - an integral part of cell membranes - inside and enclosing cells.

Phospholipids

// Structurally similar to triglycerides - one fatty acid is replaced by  a choline group.  The ________ group has both N and P in its structure.

choline

// The choline group is charged (polar) and will hydrogen bond with  water. It is called __**_________**__ (water loving).

\

__**hydrophilic**__

// The rest of the molecule is nonpolar and insoluble in water. It will  not hydrogen bond with water. It is __**_________**__ (water fearing).

\

__**hydrophobic**__

// Because phospholipids have two very different tendencies toward  water they are called __**__________.**__

amphiphilic molecules

/ The choline end of the molecule is called the “head.”  The fatty  acid chains are called the “tails.”  Phospholipids have hydrophilic ___ and hydrophobic _____.

heads; tails

// In water,  phospholipids  spontaneously form  **________** or **_______** with their heads  pointing outwards and  their tails associating  with each other and  avoiding water.

micelles; bilayers  

/ T/F: Steroids or Sterols have a more complex structure than other  lipids and a greater diversity of functions.

TRUE

/ T/F: Cholesterol is NOT an important  part of cell membranes

FALSE

/ T/F: Vitamin D is necessary for  some biochemical reactions  to occur properly. Deficiencies does not result in skeletal  abnormalities.

FALSE

/ T/F: Other steroids are hormones.  The sex hormones, testosterone, estrogen and  progesterone are steroids.

TRUE

// Proteins serve as enzymes (biological catalysts), for _____,_______,_________,___________,___________, and__ __________.

defense,  transport, support, motion, regulation, and storage.

// The 20 different amino acids each have a different

R group

// Proteins are polymers of amino acids joined through **_________**

**peptide bonds**

// A polymer of amino acids is called a __**____________.**__

polypeptide

/ T/F: All  proteins are polypeptides.  Not all polypeptides are proteins. A protein is a polypeptide that performs a function.

TRUE

// Protein structure can be classified at several different levels: ________,__ _________,__ __________,__ ____________.

primary, secondary, tertiary, and quaternary

/ Functional proteins can vary in length from about ___ amino acids  to several thousand amino acids.

50

/ **Primary (1**°**) structure** - the  amino acid sequence.

Met -Gly-His -Trp-Lys

// ___________ - other components of structure within a  protein

Motifs and Domains

/

* Motifs - super ________  structure - channels and  grooves formed by associations  of pleats and helices.
* Domains - regions of local ________ structure  along the length of a protein that have different  functions.

secondary; tertiary

// High temperatures result in weakening of H-bonds.  Proteins tend to______________(unfold) at high temperature.

* Low  temperatures ________ __H-bonds.  Proteins become__ _____at low  temperature.

vibrate; strengthen; rigid

/ ____________ (Hb) is a protein that  carries oxygen in blood.

Hemoglobin

/ **Nucleic acids** - are the  _______ __and__ __________  of information. 

repositories and carriers

// Two types of nucleic acids,

__**DNA**__ - deoxyribonucleic acid

__**RNA**__ - ribonucleic acid

Both are polymers of **__________.**

**nucleotides**

// DNA is the __________________.  It contains the information  that makes living things what they are. 

blueprint of life

/ RNA mediates the expression of this information.  RNA is  responsible for ___________

protein synthesis

/ T/F: DNA and RNA are both polymers of nucleotides.

TRUE

/ Nucleotides all have a  central ________,__ __________, and__ ______________.

* 5-carbon sugar,
* a  nitrogenous base,
* phosphate group.

// The nitrogenous bases found in DNA are ________,__ _______,__ ________, and__ ____________.

Adenine, Thymine,  Guanine and Cytosine.

// The nitrogenous bases found in RNA are Adenine, **______,**  Guanine, and Cytosine. (A,U,G,C)

**Uracil**

/ The linkage between nucleotides is called a **______________.**

phosphodiester bond

// Nucleic acids have a

nitrogen-containing bases, phosphate groups, and sugar molecules.

/ T/F: The sugars are oriented  from their #5 carbon to their  #3 carbon.  The entire  polymer has a 5’ ®  3’  orientation.

TRUE

/ T/F: Both DNA and RNA are  synthesized by adding new  nucleotides to the 3’ end of  the chain.

TRUE

// DNA is a double stranded molecule.  The two strands wrap around each other, each as a helix.  DNA  is a _____________.__

double helix

// The two strands of DNA  run in opposite directions.  They are ________________.__

complementary/ antiparallel

// **ATP** (**A**denosine **T**ri**P**hosphate)  is the ______

source of energy

//The bonds between the phosphate groups are **_______________.**

high-energy bonds

__NAD__ _________________ is composed of  two nucleotides.

__**N**__icotinamide __**A**__denine  __**D**__inucleotide