Chapter 4 Flashcards
What is the polarity of water? (4)
- water is an inorganic compound, consists of hydrogen & oxygen elements
- water molecules are polar molecules because shared electron between H & O will be attracted towards O2 which is more electronegative
- polarity produced hydrogen bonds & allows water to act as universal solvent
- allows solutes (glucose, electrolytes) to be transported through the plasma membrane into cells for biochemical reactions
What is cohesive force & adhesive force of water? (3)
- water molecules are attached to each other through a cohesive force
- water molecules are also attached to other surfaces through adhesive force
- both forces produces the capillary action which allow water to enter & move along narrow spaces (xylem tube)
What is the specific heat capacity of water? (3)
- high specific heat capacity: 4.2 kJ/kg degree Celsius
- 4.2 kJ of heat energy is required to raise the temperature of 1 kg of water by 1 degree Celsius
- water absorbs a lot of heat energy with a small rise of temperature, this characteristic is very important to maintain the body temperature of organisms
What are organic compounds?
- chemical compounds that contain carbon elements
What is macromolecules? (3)
- large & complex molecules
- most macromolecules are polymers comprising small molecules known as monomers (building blocks)
- carbohydrates, proteins & nucleic acids are polymer molecules of organic compounds
What are the elements on carbohydrates (3), their ratio & chemical formula?
- carbon , r=1
- hydrogen, r=2
- oxygen, r=1
- chemical formula: (CH2O)n
What are the types of carbohydrates? (3)
- monosaccharides (simple sugars)
- disaccharides
- polysaccharides (complex sugars)
What are monosaccharides and their characteristics? (4)
- monosaccharides are carbohydrate monomers (simplest carbohydrate units)
- can combine to form polymers through condensation
- most taste sweet, can form crystals & dissolve in water
- has reducing power (able to transfer hydrogen/electron to other compounds)
What are some examples of monosaccharides and their characteristics? (3)
- glucose (found in plants [rice/wheat] & fruits [grapes], most common monosaccharide & most polysaccharides are formed from this sugar)
- fructose ( found in honey & sweet fruits)
- galactose ( found in milk)
What happens when monosaccharides are heated in Benedict’s solution? (2)
- when monosaccharides is heated in Benedict’s solution, the monosaccharide will reduce the blue copper (II) sulphate to brick red precipitate of copper (I) oxide (not soluble in water)
- all monosaccharides give this reaction (aka reducing sugars)
What are disaccharides? Give 3 examples.
- molecules that are formed when 2 simple sugar molecules (monosaccharides) combine through condensation to form a disaccharide unit (involves removal of a water molecule)
- sucrose (non reducing sugar)
- maltose (reducing sugar)
- lactose (reducing sugar)
How is disaccharides formed? (3 word equations)
glucose + glucose → maltose + water
glucose + fructose → sucrose + water
glucose + galactose → lactose + water
[→ symbolizes condensation]
How can disaccharides be broken down to their monosaccharide units?
- through hydrolysis & addition of 1 water molecule
What are the word equations for break down of disaccharides to their monosaccharide units? (3)
maltose + water → glucose + glucose
sucrose + water → glucose + fructose
lactose + water → glucose + galactose
[→ symbolizes hydrolysis]
What are polysaccharides and their characteristics (5)?
- sugar polymers consisting monosaccharide monomers
- formed through condensation involving 100s of monosaccharides to form long molecular chains
- not soluble in water du to large molecular size
- not sweet, des not crystallize
- can disintegrate through hydrolysis with help of dilute acid, boiling & enzyme reaction
State the importance of carbohydrate in cells (3)
- as source of energy (glucose)
- as food reserve (glycogen in animal cells, starch in plant cells)
- as a support structure ( cellulose in plant cell wall)
What are proteins and its characteristics? (3)
- a complex compound composed of carbon, hydrogen, oxygen & nitrogen ( also contain sulphur & phosphorus)
- composed of 1/more polymers (polypeptides)