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Cell Biology: Cell Compounds and Biological Molecules. Lesson 3 – Carbohydrates and Lipids ( Inquiry into Life pg. 31-36 ). Today’s Objectives. Analyze the structure and function of biological molecules in living systems, including carbohydrates, lipids, proteins, nucleic acids - PowerPoint PPT Presentation
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Cell Biology:Cell Compounds and Biological Molecules
Lesson 3 – Carbohydrates and Lipids (Inquiry into Life pg. 31-36)
Today’s Objectives Analyze the structure and function of biological molecules in
living systems, including carbohydrates, lipids, proteins, nucleic acids Demonstrate a knowledge of dehydration synthesis and hydrolysis
applied to organic monomers and polymers Differentiate among carbohydrates, lipids, proteins, and nucleic acids
with respect to chemical structure Recognize the empirical formula of a monosaccharide List the main functions of carbohydrates Differentiate among monosaccharides, disaccharides, and
polysaccharides Differentiate among starch, cellulose, and glycogen with respect to
function, type of bonding, and level of branching Describe the location, structure, and function of the following in the
human body: neutral fats, steroids, phospholipids Compare saturated and unsaturated fatty acids in terms of molecular
structure
2.4 Organic Molecules
Always contain: Carbon (C) and Hydrogen (H) A carbon atom may share electrons with
another carbon atom Can form long carbon chains (below)
Carbon Rings
Can also form carbon rings when a carbon chain turns back on itself
Called a ring compound Functional groups can be attached to carbon
chains or rings
Macromolecules Many molecules of life are
macromolecules.(macromolecules contain many molecules joined
together) Monomers:
Simple organic molecules that exist individually
Can also be called “unit molecules” Polymers:
Large organic molecules form by combining monomers
Macromolecules
Organic Molecules
A meal containing carbohydrates, lipids, and proteins.
Dehydration and Hydrolysis Reactions
Cells have mechanisms of joining monomers to build polymers Dehydration Reaction:
an -OH and -H are removed as a water molecule
Hydrolysis Reaction: the components of water are added
Dehydration and Hydrolysis Reactions
Dehydration and Hydrolysis Reactions Ex) dehydration of glucose
Organic Molecules The 4 main types of organic polymers that
we will be looking at are: Carbohydrates Lipids (fats) Proteins Nucleic Acids
All are essential to life
2.5 Carbohydrates
Some Functions:Quick fuel*Short-term energy storage*Structure of organisms
* foremost function Molecules characterized by presence of the
grouping H-C-OH Ratio if H to O is 2:1
Monosaccharides Simple Carbohydrates
Monosaccharides are sugars with 3 - 7 carbon atoms Sugars are vital fuel nutrients for cells Pentose refers to a 5-carbon sugar
All occur as ring structures with the formula C5H10Ox
Hexose refers to a 6-carbon sugarGlucose – found in our bloodFructose – found in fruitsGalactose – found in milk
All occur as ring structures with the formula C6H12O6 Exact shape of ring differs, as does arrangement of the –H
and –OH groups attached
Monosaccharides - Glucose
Three ways to represent the structure of glucose.
Monosaccharides
GLUCOSE FRUCTOSE GALACTOSE
Disaccharides Disaccharides contain two bonded monosaccharides
Have a common formula C12H22O11 Common disaccharides:
Maltose - two molecules of glucose Sucrose – one glucose, one fructose Lactose – one glucose, one galactose
Polysaccharides Polysaccharides are long polymers that
contain many glucose subunits. basic formula (C6H10O5)n
n= dozens to thousands of glucose units Three main types:
Starch is the storage form of glucose in plants. Glycogen is the storage form of glucose in
animals. Cellulose can be found in the cell walls of
plants.
Polysaccharides
Glycogen Starch Cellulose
Starch Storage form of
glucose in plants Few side chains of
glucose Linkage between
glucose units are the same
Figure 2.17 pg. 33
Glycogen “animal starch” stored
in the liver and muscle tissue
Storage form of glucose in animals
Many side chains of glucose
Linkage between glucose units the same
Figure 2.18 pg. 33
Cellulose Gives plants its
structure Found in the cell walls
of plants No side chains of
glucose Different linkages
between glucose units Fig. 219 pg. 33
Cellulose Our digestive
system is unable to digest this linkage.
Cellulose passes through our system as fiber or roughage.
May be important for good health and prevention of colon cancer
Summary of Carbohydrates 1) Source of short-term energy for all
organisms: Animals – glycogen Plants – starch Energy is released as the carbohydrates are
broken down by hydrolysis 2) Structural molecules in plants - cellulose
2.6 Lipids Include:
Fats and Oils Phospholipids Steroids
We eat lipids as part of our food. Our bodies are capable of producing them as well as metabolizing them
Next to glucose, fats are the second most important energy molecule for us
Unfortunately, we store them in adipose (fat) cells
Lipids Some functions:
Long-term energy storage Insulation against heat loss Protection of major organs Primary component of the cell membrane
Molecules also contain carbon, hydrogen, and oxygen but the H:O ratio is greater than 2:1
Lipids do not dissolve in water (non-polar) Lipids are electrically neutral
Lipids Fats and Oils
Fats (saturated fats) Usually of animal origin Solid at room temperature Fats provide long-term energy storage,
insulate against heat loss, and protect major organs
Ex.) lard, butter Oils (unsaturated fats)
Usually of plant origin Liquid at room temperature Ex.) vegetable oils
Formation of Fats Fats and oils form when one glycerol
molecule reacts with three fatty acid molecules
A fat molecule is sometimes called a triglyceride because of its three-part structure
The term neutral fat is sometimes used because the molecule is non-polar
Neutral Fat Structure
Synthesis and degradation of a fat molecule
Fatty Acids Saturated and Unsaturated Fatty Acids
Fatty acids are hydrocarbon chains that end with an acidic group -COOH.
Saturated fatty acids: No double covalent bonds between carbon
atomsCarbon atoms are “saturated” with as many
hydrogen atoms as they can hold
Unsaturated fatty acids: Have some double bonds between carbon
atoms (wherever the number of hydrogens is less than two per carbon atom)
Fatty Acids
Saturated Fatty Acid
Unsaturated Fatty Acid
-COOH acidic group
Carbon double bond
Phospholipids Phospholipids are a variation of a
triglyceride where one of the 3 fatty acids is replaced with a phosphate and nitrogen-containing group
Primary components of cellular membranes
Phospholipids The phosphate group creates a polar
region on one end of the phospholipid This allows phospholipids to mix with both
polar (hydrophilic) and non-polar (hydrophobic) materials
Phospholipids The heads of the
phospholipids are polar and are said to be water loving (hydrophilic)
The tails of the phospholipids are non-polar and are said to be water fearing (hydrophobic)
Phospholipid Structure
Cell Membrane The structure of phospholipids make them
a very important part of cells as they form much of the cell membrane
Steroids Assist in protein synthesis Insoluble in water All steroids have four adjacent carbon rings. Examples:
Cholesterol important part of the cell membrane Protective cover around nerve fibers
Testosterone Male sex hormone
Estrogen Female sex hormone
Structure of Steroids
All steroids have four adjacent carbon rings, but their attached groups differ. The effects on the body largely depend on the difference in the attached groups (shown in blue)
Cholesterol Formed by the body and also enters
body as a part of our diet Important part of the cell membrane and
protective cover around nerve fibers Cholesterol is important but often results in
fatty deposits inside arteries which narrows the pathway for blood to the heart
Can result in high blood pressure
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