The document provides an overview of biochemistry, focusing on the chemical processes within living organisms and the structure and function of cells. It distinguishes between eukaryotic and prokaryotic cells, outlines various cell components and their functions, and elaborates on the composition of cells. Key topics include the roles of organelles such as the nucleus, mitochondria, and endoplasmic reticulum, along with the biochemical composition of cells.

1. Bio Chemistry
By Dr Saima Memon

2. Introduction
 Name
 City
 Best quality
 Area of improvement

3. Bio Chemistry
 Biochemistry is the branch of science that explores
the chemical processes within and related to living
organisms. It is a laboratory-based science that
combines principles of biology and chemistry to
understand the molecular mechanisms that govern
life. Biochemistry focuses on the structure, function,
and interactions of biological molecules such as
proteins, nucleic acids, lipids, carbohydrates, and
enzymes.

4. Lecture -1
Cell

5. Bio Chemistry
At The end of this session you should able to
understand
1. CELL
a) Describe the structure of cell and its bio chemical
composition
b) Differentiate between eukaryotic and prokaryotic cell
c) Describe various cell membrane proteins
d) Discuss cell receptors and different signaling
mechanism

6. What is Cell?
The cell is the functional basic unit of life. It
was discovered by Robert Hooke and is the
functional unit of all known living organisms.

7. Shape of cells
Generally, cells are round, spherical or
elongated some cells are long and pointed at
both ends. They exhibit a spindle shape. Cells
sometimes are quite long. Some are branched
like nerve cells or a neuron. Some are sphere
like RBC.

8. Unicellular and multicellular
Organisms, such as most bacteria, are
unicellular (consist of a single cell). Other
organisms, such as humans, are multi cellular.
Humans have about 100 trillion cells

9. Types of Cell
There are two types of cells:
1. Eukaryotic cell
2. Prokaryotic cell

10. Types of cell
white blood cell
red blood cell
cheek cells
sperm
nerve cell
muscle cell
Amoeba
Paramecium

11. Difference.

12.  Cells are composed of several components:
 1. Cell Membrane: A phospholipid bilayer that
controls the entry and exit of substances.
 2. Cytoplasm: Gel-like substance containing
organelles and cytosolic molecules.
 3. Nucleus: Contains genetic material (DNA) in
eukaryotic cells.
Structure of cell

13.  4. Organelles: Mitochondria: Powerhouse of
the cell, produces energy (ATP).
Ribosomes: Synthesize proteins.
Endoplasmic Reticulum: Rough (protein
synthesis) and Smooth (lipid synthesis).
Golgi Apparatus: Modifies, sorts, and packages
proteins.
Lysosomes: Contain enzymes for digestion.
Chloroplasts (in plants): Site of photosynthesis.
Structure of cell

14. Organelles of Cell
Very small size
Can only be observed under a microscope
Have specific functions
Found throughout cytoplasm
Endoplasmic reticulum (rough & smooth) ; Golgi
Bodies;Nucleolus; Lysosomes; Ribosomes

15. Cytoplasm of a Cell
Jelly-like substance enclosed by cell membrane
Provides a medium for chemical reactions to take
place
Cytoplasm

17. Cell nucleus
The cell nucleus is the most conspicuous
organelle found in a eukaryotic cell. It houses
the cell's chromosomes, and is the place where
almost all DNA replication and RNA
synthesis (transcription) occur. The nucleus is
spherical and separated from the cytoplasm by
a double membrane called the nuclear envelope.

18.  DNA replication and RNA transcription of DNA
occur in the nucleus.
 The nucleolus is non-membranous and
contains RNA polymerase, RNAase, ATPase
and other enzymes but no DNA polymerase.
 Nucleolus is also the major site where
ribosome subunits are assembled.
functions

20. Mitochondria
Mitochondria are present in eukaryotes only.
Mitochondria are self-replicating organelles
that occur in various numbers, shapes, and
sizes in the cytoplasm of all eukaryotic cells.
Mitochondria play a critical role in
generating energy in the eukaryotic cell.

22. Endoplasmic reticulum
The ER has two forms: the rough ER, which
has ribosomes on its surface and secretes
proteins into the cytoplasm, and the smooth
ER, which lacks them. Smooth ER plays a role
in calcium sequestration and release.

23. There are two kinds of endoplasmic reticulum
(ER)
 i) Rough surfaced ER
 ii) Smooth surfaced ER
Function of rough ER: Rough ER synthesizes
membrane lipids, and secretory proteins.
These proteins are inserted through the ER
membrane into the lumen of the cisternae
where they are modified and transported
through the cell.
Types

24.  Function of smooth ER: Smooth endoplasmic
reticulum is involved:
(i) In lipid synthesis and
(ii) Modification and transport of proteins
synthesized in the rough ER.

25. Endoplasmic reticulum

26. The ribosome
The ribosome is a large complex of RNA and
protein molecules. They each consist of two
subunits, and act as an assembly line where
RNA from the nucleus is used to synthesize
proteins from amino acids. Ribosomes can be
found

27. Ribosomes

28. Lysosomes and Peroxisomes
Lysosomes and Peroxisomes are present in
eukaryotes only. Lysosomes contain
digestive enzymes (acid hydrolases). They digest
excess or worn-out organelles, food particles,
and engulfed viruses or bacteria. Peroxisomes
have enzymes that rid the cell of toxic
peroxides.

29. Lysosomes and Peroxisomes

30.  Cells are primarily composed of:
 1. Water (~70%): Acts as a solvent for
biochemical reactions.
 2. Proteins: Enzymes, structural components,
and signaling molecules.
 3. Lipids: Form the cell membrane and store
energy.
 4. Carbohydrates: Provide energy and
structural support.
Biochemical Composition of a Cell

31.  5. Nucleic Acids: DNA and RNA, carriers of
genetic information.
 6. Ions and Small Molecules: Calcium,
potassium, sodium, etc., for cellular processes.
Biochemical Composition of a Cell

32. It’s You!
Thank You