Biology 1 SYAZWAN TAQIF (SB015)

1ST SEMESTER

Biology 1 (SB015)

Assignment 2022/2023
BIO FLIPBOOK : Molecules
Of life & Cell Structures and functions

Name : Syazwan Taqif Bin Juhairul
Matric Numbers : MS2213201476

Practicum : K4T03B
Set of Question : Set B
Lecturer Name : Habibah Binti Mohamad Rejab

Contents of this slides :

Here’s the question that we gonna discuss in this Slides :

i. State the main types of molecules of life (5 marks)
ii. Classify carbohydrates into three main classes based on their structure and

characteristic (15 marks)
iii. Humans are unable to digest vegetables,but herbivores are able to do

so.Explain this statement by focusing on a significant structure of the plant
cell (10 marks)
iv. Name the organelle which synthesises carbohydrates in plant cells.Describe
how the organelles structures are involved in the synthesis of carbohydrates.
(5 marks)

i. State the main types of
molecules of life (5 marks)

Hello!

The main type of molecules of life included
water,carbohydrates,proteins,lipids and
DNA and RNA molecules.

ii. Classify carbohydrates into three main classes based

on their structure and characteristic (15 marks)

Carbohydrates are divided into THREE main classes which are :

1. MONOSACCHARIDES

It is the simple sugar among the carbohydrates classes which
cant be broken down into smaller molecules by hydrolysis like
the other carbohydrates classes.

Characteristic of monosaccharides includes sweet-tasting,
soluble in water, can be crystallised and is a reducing agent
because it has a free ketone and aldehyde group which can
donate electrons to other molecules.

It can be the monomers for disaccharides & polysaccharides.The
general formula of monosaccharides is (CH₂O)n. n equals to
number of Carbon atoms (C) in the molecules.

2. Disaccharides

• Disaccharides is made of two
monosaccharides through
condensation reaction.

• Through condensation
reaction,one water molecule
is removed.

• The fusion of these two
monosaccharides is linked by
glycosidic linkage.Glycosidic
linkage is covalent bond
formed between two
monosaccharides by a
condensation reaction.

• Characteristic of
disaccharides are
sweet,water soluble, can be
crystallised and can be
broken down through
hydrolysis.

3. Polysaccharides

Polysaccharides are polymers formed
when hundreds of monosaccharides
joined by glycosidic linkages through
condensation.Polysaccharides can be
broken down through hydrolysis.

The chains formed may be variable in
length,branched or
unbranched,folded(ideal for energy
storage) and straight or coiled.

Characteristic of polysaccharides
includes
large/macromolecule/complex,not
sweet,insoluble in water and cannot be
crystallised.

The three example of polysaccharide are
starch,glycogen and cellulose.

iii. Humans are unable to digest vegetables,but herbivores are able to do so.Explain this
statement by focusing on a significant structure of the plant cell (10 marks)

The outermost layer of every plant cell is the cell wall, which is made of fiber-like compounds like cellulose,
hemicellulose, and lignins..Cellulose is a polysaccharides consists of many β-glucose molecules that joined by β,1-
4,glycosidic bond.These fibrous compound can be digested with availability of cellulase enzyme inside the body.
Human can’t digest these fibrous compounds since we lack the necessary enzyme cellulase.

Cellulose can be broken down through hydrolysis catelysed by cellulase.In general, humans can eat seeds, fruits,
vegetables, roots, and many other plant parts. That said, our bodies aren’t able to digest them all completely
because we lack of cellulase.

Herbivores like cows, goats, and deer likewise can’t produce cellulase on their own. However, they have friendly
gut bacteria that produce it for them — while humans don’t have such gut bacteria to produce cellulase
enzyme.The gut bacteria help breaking down cellulose,thus digesting the vegetable in gut of herbivore.

iv. Name the organelle which synthesises carbohydrates in plant cells.Describe how
the organelles structures are involved in the synthesis of carbohydrates. (5 marks)

The organelle which synthesizes
carbohydrates in plant cell is
chloroplast.Chloroplast is an organelle
in plant cell that function to carry out
the process of photosynthesis.
Photosynthesis is a process where
plant produce carbohydrate.In
plant,this choloroplast has thylakoid
that contain chlorophyll inside it.The
chlorophyll will trap the light energy
from the sunlight.Then, enzymes in
stroma will catalysed the synthesis of
sugar and carbohydrate.