Digestive System Flashcards
What chemical elements are present in carbohydrates?
C,H,O
What do carbohydrates serve as?
A readily available energy source
What’s one way to identify simple carbohydrates?
Many end in ose (glucose, sucrose, maltose, lactose)
What are monosaccharides?
Building blocks for other types of carbohydrates
What is the general chemical formula for most monosaccharides
Some multiple of CH2O (glucose - C6 H12 06)
What is the shape of monosaccharides?
Open chains or in rings
What are isomers?
When they have the same chemical formula but are structurally different - many monosaccharides are isomers
What are disaccharides
Consists of two monosaccharides joined together
What is ingestion
The taking in of nutrients
What is digestions
The breakdown of organic molecules into smaller complexes
What is absorption
The transport of digested nutrients to the tissues of the body
What is egestion
The removal of materials from the body that the body cannot digest
What is physical digestion/mechanical digestion
It involves chewing, mixing with saliva, emulsifying, squeezing and churning. The purpose is to increase surface area to make chemical digestion more efficient
What is chemical digestion
Involves the breaking of large molecules by enzymes using the process of hydrolysis
What are examples of foods containing simple carbohydrates?
Fruit, sugar cane, sweet potatoes, yams
How are monomers linked together?
By the removal of a water molecule in a
process called dehydration synthesis
What are complex carbohydrates made up of?
A few hundred to a few thousand monosaccharides linked together
What are complex carbohydrates used as?
Storage material in plants and animals and as structural components such as cell walls in plants
What is a starch
The storage polysaccharide of plants
What are starchs made up of?
Only glucose
What are the two different types of structure in starches
Amylase and amylopectin
What is amylase
helical and straight line configuration
What is amylopectin?
Branched
What are examples of starches?
Potatoes, grains, corn, rice, pasta
How do plants store glucose from photosynthesis?
As starch and withdraw starch as needed
What is glycogen?
The storage polysaccharide of animals
Which is more branched? Amylopectin in plants or glycogen?
Glycogen (animals)
Where is glycogen stored?
In the liver and muscle cells
What is the most abundant organic compound on the earth’s surface?
Cellulose
What does cellulose do?
Encloses plant cells
What is cellulose made of?
Glucose (like starch) but has a different bonding arrangement
What is the structure of cellulose?
A linear molecule ideal for forming “strands” in a “rope”
Can humans digest cellulose for energy?
No but it is useful as dietary fibre (adds bulk to the formation of a stool)
Where is chitin found?
exoskeletons of insects, spiders and crustaceans
What do fungi use instead of cellulose for their cell walls?
Chitin
How can you identify the presence of reducing sugars?
The Benedict’s test
Are all monosaccharides reducing sugars?
Yes
Are all disaccharides reducing sugars?
Only some
Are polysaccharides reducing sugars?
No
What happens when the Benedict’s reagent (light blue) is mixed with a reducing sugar and heats up?
Changes to a yellow green or brick red colour
What does the iodine test identify?
Starches