BIOLOGY 1 (SB015) ASSIGNMENT 2026/2027 - BIO FLIPBOOK: MOLECULES OF LIFE & CELL STRUCTURES AND FUNCTIONS BIOLOGY 1 (SB015) ASSIGNMENT 2026/2027 - BIO FLIPBOOK: MOLECULES OF LIFE & CELL STRUCTURES AND FUNCTIONS BIOLOGY 1 (SB015) ASSIGNMENT 2026/2027 - BIO FLIPBOOK: MOLECULES OF LIFE & CELL STRUCTURES AND FUNCTIONS NAME: AININ SOFIYA BINTI ASMIFAISAL MATRIC NUMBER: MS2613108428 PRACTICUM: K2T05A LECTURER’S NAME: PN KHAIRUL ANIDA BINTI OMAR NAME: AININ SOFIYA BINTI ASMIFAISAL MATRIC NUMBER: MS2613108428 PRACTICUM: K2T05A LECTURER’S NAME: PN KHAIRUL ANIDA BINTI OMAR NAME: AININ SOFIYA BINTI ASMIFAISAL MATRIC NUMBER: MS2613108428 PRACTICUM: K2T05A LECTURER’S NAME: PN KHAIRUL ANIDA BINTI OMAR
I. State the main types of molecules of life MOLECULES OF LIFE WATER Carbohydrates Lipids Proteins Nucleic acids
MONOSACCHARIDE Structure Characteristics Examples Biological Role Simplest form of carbohydrates, consisting of single sugar units. They cannot be hydrolyzed into smaller carbohydrates by hydrolysis Sweet-tasting soluble in water Can be crystallized Act as reducing agent Glucose (primary energy source in cells) Fructose (fruit sugar) Galactose (milk sugar) They are the monomers that form disaccharides and polysaccharides II. Describe the three main classes of carbohydrates based on their structure and characteristics. There are 3 main classes of carbohydrate : Monosaccharide, Disaccharides, Polysaccharides
DISACCHARIDES Structure Characteristics Examples Biological Role Formed when two monosaccharides linked together by join a glycosidic bond form by through a condensation reaction Double sugar consists of two monosaccharide Disaccharides can be broken into monosaccharides through hydrolisis Sweet tasting Soluble in water Can be crysallized Sucrose (glucose + fructose) – Cane sugar Lactose (glucose + galactose) – milk sugar Maltose (glucose + glucose) - Malt sugar The main form that is transported in plant Source of energy
POLYSACCHARIDES Structure Characteristics Examples Biological Role Polymers consisting of many monosaccharides joined together by glycosidic bonds Formed through (repeated) condensation reactions Can be broken down into simpler sugars by hydrolysis Large and complex Not sweet Insoluble in water Cannot be crytallized Starch – energy storage in plants Glycogen – energy storage in animals, especially in liver and muscles Cellulose – structural component of plant cell walls Chitin – structural component in exoskeletons of insects and crustaceans Provide long-term energy storage Offer structural support in plants and animals
III.Name the organelle which synthesizes carbohydrates in plant cells. Describe how the organelle’s structures are involved in the synthesis of carbohydrates. 1.Organelle which synthesizes carbohydrates in plant cells is chloroplast. To synthesizes carbohydrates through photosynthesis. 2.Chloroplast has : Chlorophyll Stroma Thylakoids 3.Thylakoids contains chlorophyll to trap light energy for photosynthesis 4.The stroma of chloroplast contains enzymes. The enzymes are required for the synthesis of glucose. The glucose formed can be used to synthesize other carbohydrates such as starch, sucrose and cellulase
IV. Humans are unable to digest vegetables, but herbivores are able to do so. Explain this statement by focusing on a significant carbohydrate- based structure of the plant cell. Plant cells have cell wall composed of cellulose. Cellulose is a polysaccharide consisting of long, unbranched chains of β-glucose molecules linked by β-1,4 glycosidic bonds. These chains form microfibrils, which are tightly packed and held together by hydrogen bonds, giving the plant cell wall great strength and rigidity. Cellulose is the main structural component of plant cell walls, providing support and protection. Cellulose can be broken down through hydrolisis catalyzed by enzymecellulase. Humans are unable to digest vegetables due to the lack of enzyme cellulase, which is required to break the β-1,4 glycosidic bonds in cellulose. As a result, cellulose passes through the human digestive system undigested, acting only as dietary fiber that aids bowel movement but does not provide energy. The human digestive enzymes (like amylase) can only break α-1,4 bonds found in starch, not the β-bonds in cellulose. Herbivores such as cows, goats, and rabbits have symbiotic microorganisms (bacteria and protozoa) in their digestive systems that produce cellulase. In ruminants (e.g., cows), these microbes live in the rumen, where they break down cellulose into glucose and volatile fatty acids, which the animal can absorb and use for energy. Non-ruminant herbivores (e.g., horses, rabbits) have similar microbes in their cecum or large intestine that perform the same function.