Biology Unit 1

What are macromolecules?

Big & complex molecules that are composed of many covalently connected atoms

What are the molecules of life?

1) Lipids

2) Proteins

3) Carbohydrates

4) Nucleid acids

What is a monomer?

Small, repeating building blocks

What is a polymer?

Composed of many monomers

What are examples of polymers?

1) Nucleic acids

2) Carbs

3) Proteins

How can polymers be synthesized?

Through a dehydration reaction

(2 monomers are bonded together and a molecule of water is lost)

How can a polymer be broken down?

Through a hydrolysis reaction

(A water molecule is added, breaking the bond and disassembling a polymer into monomers)

What are the types of carbohydrates?

• Monosaccharides, Polysaccharies & Dissacharides

What is a monosaccharide?

A single sugar

Usually have a molecular formula that is a multiple of CH2O (i.e. glucose)

What is a polysaccharide?

Polymers composed of many sugar building blocks

What are the cellular functions of Monosaccharides?

• Major fuel source

• Serve as raw material for building larger organic molecules

What is a glycosidic linkage?

The bond when a dehydration reaction joining two monosaccharides and forming a disaccharide

Examples of dissacharides?

• Glucose, fructose & maltose

What are polysaccharides?

Polymers of sugar that have storage & structural roles

Examples of polysaccharides?

• Starch

• Glycogen

• Cellulose

• Chitin

What do the sugar monomers & position of its glycosidic linkages determine in polysaccharides?

It’s structure & function

Where is starch found?

In plants

What is the function of starch?

A storage of polyssacharides in plants

What is the function of glycogen?

A storage polysaccharide in animals

Why is glycogen branched?

As it is quickly able to release glucose

What is the function of cellulose?

A major component of plant cell walls

What is the difference btween cellulose mifrofibrils & cellulose molecules?

A cellulose molecule is a single, unbranched polymer chain made of thousands of \(\beta \)-glucose units, whereas a cellulose microfibril is a larger, cable-like bundle formed when multiple individual cellulose molecules align and link together

What is chitin?

A structural polysaccharide found in arthorpod exoskeletons and fungal cell walls

Why are lipids hydrophobic?

They consist mostly of hydrocarbons that are non-polar.

What are important lipids?

Fats, phospholipids & steroids

What is glycerol?

Has a 3 carbon group with hydroxyl attached to each carbon

What are fatty acids?

Carboxyl groups linked to a long hydrocarbon chain

What types of fatty acids are there?

Saturated & unsaturated

What defines a saturdated fatty acid?

• No double bonds (Holding as many hydrogens as possible)

• Solid at room temp

What defines an unsaturdated fatty acid?

• One or more double bonds

• Liquid at room temp

What is hydrogenation?

The process of coverting unstaurated to saturdated fats by adding hydrogen

What is the function of fat?

Energy storage

Where do humans and other mammals store their fat?

In adipose cells

What is the structure of phospholipds?

• Glycerol linked to 2 fatty acid tail (hydrophobic) & one phopshate head group that is (hydrophilic)

What is the function of phospholipids?

Major component of cell membranes

What are steroids?

Lipids with a carbon skeleton consisting of four fused rings

What do protein functions include?

• Speeding up chemical reactions

• structural support

• storage

• transport

• cellular communications

• movement

• defence against foreign substances

What are enzymes?

Types of proteins that act as a catalyst

What is the function of hormonal proteins?

Coordination of an organisms activities

What is the function of storage proteins?

Storage of amino acids

What is the function of contractile and motor proteins?

Movement

What is the function of defensive proteins?

Protection against disease

What is the function of receptor proteins?

Response of cell to chemical stimuli

Function of structural proteins?

Support

What are polymers?

Constructed from a set of 20 amino acids

What are polypeptides?

Long unbranched chains of animo acids linked together by peptide bonds

What are proteins?

One or more polypeptide

What makes up an amino acid?

An amino group and a carboxyl group

What are the types of amino acids?

Non-polar, polar & charged amino acids

Characteristics non-polar amino acids?

• Hydrophobic

• Hidden inside proteins to avoid H2O

Characteristics of polar amino acids?

• Hydrophilic side chains

• on the outside of proteins (like H2O)

Characteristics of charged amino acids

• Hydrophilic (like polar amino acids)

What is a peptide bond?

Former by dehydration reactions, that link the carboxyl group of 1 amino acid to the next (n-terminus to c-terminus)

What does protein function depend on?

The folding of polypeptides into a 3D shape

What is the definition of protein function?

The ability to recognize & bind other molecules

What are the levels of protein structure?

Primary, Secondary, Tertiary & Quaternary

What is primary structure?

• The unique amino acid sequence (determines by inherited genetic information)

What is secondary structure?

• The coils and folds within a polypeptide chain

• Coil structure (alpha-helix)

• Folded structure (beta-pleated sheet)

• Determined by hydrogen bonding of the backbone

What is the tertiary structure?

• Overall shape of a polypeptide

• Determined by interactions among the side chains (R groups)

What is quaternary structure?

When a protein consists of multiple polypeptide chains (i.e. collagen or hemoglobin)

What other factors determine protein structure?

• pH, salt concentration & temperature can all cause denaturation (proteins unravel & lose their natural shape)

What methods can be used to determine protein structure?

1) X-ray crystallography

2) Nuclear magnetic resonance spectroscopy

What is a gene?

A unit of inheritance that programs the amino acid sequences of a polypeptide

What is DNA made up of

Made up of monomers called nucleotides

What are the types of nucleic acids?

1) Deoxyribonucleic acid (DNA)
2) Ribonucleic acid (RNA)

What is the central dogma of molecular biology?

• Describes how genetic information flows

• DNa makes exact copies of itself that are then copied into mRNA → ribosomes read the RNA message and link amino acids together to build a functional protein

What are nucleic acids made up of?

Nucleotides that contain (a five carbon sugar, a phosphate group and a nitrogen-containing base)

• Sugar: deoxyribos or ribose

• Nitrogen base: Purine (Adenine, Guanine) (2 circular structures) or Pyrimidines (Cytosine, Thymine, Uracil) ( 1 circular structure)

DNA pairing?

Adenine & Thymine

Guanine & Cytosine

RNA pairing?

Adenine & Uracil

Guanine & Cytosine

What is bioinformatics?

Use of computers to deal with data resulting from the sequencing of many genomes

What is genomics?

Analysis of a large set of genes

What is proteomics?

Analysis of a large set of proteins

What does a nucleoside refer to?

Nitrogenous base & sugars

What does a nucleotide refer to?

Everything (nitorgenous base, 5 carbon sugar & phosphate group)

What are the three parameters of microscopy?

1) Magnification

2) Resolution

3) Contrast

What are the three types of microscopies?

1) Light microscopy

2) Scanning electron microscopy

3) Transmission electron microscopy

What is light microscopy?

When visible light is passed through a specimen and then through a glass lense

• Is useful to look at live cells

• Can stain to better see parts of the cell (enhances contrast)

What are the types of light microscopy?

Fluorescence Microscopy, Confocal Microscopy, Deconvolution, Super-Resolution Microscopy

What is fluorescence microscopy?

When specific molecules are visualized with fluorescently-labelled dyes or antibodies

• Allows for the differentiation of different parts of the cell

What is confocal microscopy?

Uses lasers to produce sharper images & allows 3D image reconstruction

What is deconvolution?

Digital processing of fluorescence images (results in sharper 3d images)

What is super-resolution microscopy?

Allows more resolution of smaller units

What is scanning electron microscopy?

Focusing a beam of electrons onto the surface of a specimen to provide 3D images

What is transmission electron microscopy?

Focuses a beam of electrons through a specimen to study internal structures

What is cell fractionation?

• break cells open and separate organelles using a centrifuge and different densities

What defines a prokaryotic cell?

• No nucleus

• DNA in an unbound region called the nucleoid

• Non-membrane-bound organelles

• Cytoplasm is bound by plasma membrane

What are composed of prokaryotic cells?

• Bacteria & Archaea

What defines a eukaryotic cell?

• DNA in a nuclus bounded by a membranous nuclear envelope

• Membrane-bound organelles

• Cytoplasm between plasma membrane & nucleus

• Generally larger than prokaryotic cells

What is composed of eukaryotic cells?

Protists, fungi, animals & plants

What is the key difference between eukaryotes & prokaryotes?

Eukarotes have a nucleus & are larger than prokaryotes

What is the function of the plasma membrane?

• To be selectively permeable

• Allow the passage of sufficient amounts of oxygen, nutrients & waste to support the cell volume

True or false, small cells have a greater surface area relative to volume?

True

What cell structures are unique to plants?

• Chloroplasts

• Large central vacuoles

• Cell walls

• Plasmodesmata

Where is DNA found in eukaryotic cells?

Mainly in the nucleus, but also in the mitochondria & chloroplasts

What encloses the nucleus

A nuclear envelope that is a double membrane

What are chromosomes?

The units DNA is organized into in the nucleus

What is chromatin?

DNA tightly packaged in proteins

What is the nuclear lamina?

Maintains the shape of the nucleus

What is the nucleoulis?

The site of ribosomal synthesis

What is a ribosome?

Particles made of ribosomal RNA & protein