Cells are the basic structural and functional units of all living organisms. They were first observed by Anton Von Leeuwenhoek in the 1600s. In the 1830s, Schleiden and Schwann formulated the cell theory which states that all living things are composed of cells, cells are the basic units of structure and function, and new cells are produced from existing cells. Cells come in different shapes and sizes depending on their function, and contain various internal structures like the nucleus, mitochondria, chloroplasts, and cell membrane. Cell functions are adapted to their specific roles through specialized structures and properties.

2. Cells as the basic structural unit of all organisms
 Cell is the fundamental structural and functional unit of all living
organisms. Anton Von Leeuwenhoek first saw and described a live
cell.
 Schleiden and Schwann (1839) together formulated the cell
theory.
 Rudolf Virchow (1855) first explained that cells divided and new
cells are formed from pre-existing cells (Omnis cellula-e cellula).
 He modified the hypothesis of Schleiden and Schwann
(i) all living organisms are composed of cells and products of cells.
(ii) all cells arise from pre-existing cells.

3. Different shapes of cells

4. Comparison of eukaryotic cell with other organisms

5. Cell Function Adaption
Leaf cell Absorbs light energy for
photosynthesis
Packed with chloroplasts. Regular
shaped, closely packed cells form a
continuous layer for efficient
absorption of sunlight.
Root hair cell Absorbs water and mineral ions
from the soil
Long 'finger-like' process with very
thin wall, which gives a large
surface area.
Sperm cell Fertilises an egg cell - female
gamete
The head contains genetic
information and an enzyme to help
penetrate the egg cell membrane.
The middle section is packed with
mitochondria for energy. The tail
moves the sperm to the egg.
Red blood cells Contain haemoglobin to carry
oxygen to the cells.
Thin outer membrane to let oxygen
diffuse through easily. Shape
increases the surface area to allow
more oxygen to be absorbed
efficiently. No nucleus, so the whole
cell is full of haemoglobin.
Adaptations of cells related to their Functions

7. https://www.bbc.co.uk/education/guides/z9hyvcw/revision/4
Adaptations of cells related to their Functions

8. The main sub-cellular structures of eukaryotic & prokaryotic cells

9. Eukaryotic Plant Cell

10. Eukaryotic Animal Cell

11. Prokaryotic Cell

12. Mitochondria
It was discovered by Carl Benda in 1898

13. Chloroplast
This origin of chloroplasts was first suggested by the Russian biologist
Konstantin Mereschkowski in 1905

14. Nucleus
It was discovered in1898 by Italian physician Camillo Golgi

15. Golgi Bodies/Dictyosomes
It was discovered in1898 by Italian physician Camillo Golgi

16. Endoplasmic Reticulum
Reticulum were first seen in 1945 by Keith R. Porter

17. Stem cells in Animals
 Stem cells are present in many organs and tissues, including
brain, bone marrow, peripheral blood, blood vessels, skeletal
muscle, skin, teeth, heart, gut, liver, ovarian epithelium, and
testis. They are thought to reside in a specific area of
each tissue called a "stem cell niche".
 Plant stem cells are innately undifferentiated cells located
in the meristems of plants. Plant stem cells provides a steady
supply of precursor cells to form differentiated tissues and
organs in plants.

19. Meristems in Plants
A meristem tissue in plants contains the
undifferentiated cells (meristematic cells),
found in zones of the plant where growth
can take place.
1. Apical meristem
Apical meristems are found in two locations: the root and the stem.
Some arctic plants have an apical meristem in the lower/middle
parts of the plant because it is advantageous in Arctic conditions

20. 2. Intercalary meristem
This is present at internodes, or stem regions between the places at
which leaves and leaf bases attach, especially of certain
monocotyledons—e.g., grasses; horsetails, nodes of bamboo
3. Lateral Meristem
This is present in all woody plants, some herbaceous ones. These
plants have vascular cambium and the cork cambium. They produce
secondary tissues from a ring of vascular cambium in stems and
roots

21. Root Apical Meristem

23. Floral Meristem
They refer to a group of undifferentiated dividing cells that are
responsible for the formation of floral organs.

25.  Enzymes are proteinaceous macromolecules which act as
biological catalysts. They accelerate rate of chemical reactions.
The molecules upon which enzymes may act are
called substrates and the enzyme converts the substrates into
different molecules known as products.
 Almost all metabolic reaction in occurring
the cell need enzymes in order to occur at rates fast enough to
sustain life.
Enzymes

26. 1. Enzyme Concentration
Factors affecting Enzymes Activity
By increasing the enzyme concentration, the maximum
reaction rate greatly increases. However, enzymes become saturated when
the substrate concentration is high

27. 2. Substrate Concentration
If the substrate concentration is gradually increased, the reaction
velocity will increase until it reaches a maximum. After this point,
increases in substrate concentration will not increase the velocity (delta
A/delta T).

28. +1
, K-1
and K+2
being the rate constants from equation (7). Michaelis developed the following

29.  A small Km indicates that the enzyme requires only a small amount
of substrate to become saturated. Hence, the maximum velocity is
reached at relatively low substrate concentrations.
 A large Km indicates the need for high substrate concentrations to
achieve maximum reaction velocity.
 The substrate with the lowest Km upon which the enzyme acts as a
catalyst is frequently assumed to be enzyme's natural substrate.
Michaelis Constant (Km)

30. 3. Effects of Inhibitors on Enzyme Activity
http://www.worthington-biochem.com/introbiochem/inhibitors.html
Lock and Key Hypothesis of Competitive inhibition

31. Non-Competitive Inhibition

32. Substrate inhibition will sometimes occur when excessive amounts of
substrate are present. Here, the reaction velocity decreases after the
maximum velocity has been reached.
Substrate Inhibition

33. Additional amounts of substrate added to the reaction mixture after this
point actually decrease the reaction rate because of so many substrate
molecules competing for the active sites on the enzyme surfaces that they
block the sites.
Substrate Inhibition

34. 4. Temperature Effects
The rate of an enzyme-catalyzed reaction increases as the
temperature is raised. A ten degree Centigrade rise in temperature
will increase the activity of most enzymes by 50 to 100%.

35. 5. Effects of pH
Extremely high or low pH values generally result in complete loss of
activity for most enzymes. pH is also a factor in the stability of
enzymes and for each enzyme there is also a region of pH optimal
stability.
pH for Optimum Activity
Enzyme pH Optimum
Lipase (Pancreas) 8.0
Lipase (stomach) 4.0 - 5.0
Lipase (castor oil) 4.7
Pepsin 1.5 - 1.6
Trypsin 7.8 - 8.7
Urease 7.0
Invertase 4.5
Maltase 6.1 - 6.8
Amylase (Pancreas) 6.7 - 7.0
Catalase 7.0

36. The importance of cellular respiration
 Respiration is important because it produces energy that is
essential for the normal functioning of the body.
Respiration provides cells with oxygen and expels toxic carbon
dioxide.
 Plants respire all the time but can only photosynthesise when
they are in the light. Respiration uses oxygen and produces
carbon dioxide.

37. The processes of Aerobic Respiration
Aerobic respiration is the process of producing cellular energy
involving oxygen. Cells break down food in the mitochondria in a
long, multistep process that produces roughly 36 ATP. The first step
in is glycolysis, the second is the citric acid cycle and the third is the
electron transport system.
Chemical equation:
C6H12O6 + 6O2 → 6CO2 + 6H2O (glucose + oxygen -> carbon
dioxide + water).

38. The processes Anaerobic Respiration
Anaerobic respiration is a type of respiration that does not use
oxygen. It can be summarised by the following equation:
Glucose → lactic acid (+ energy released)
Examples of anaerobic exercise include heavy weight training,
running or cycling and jumping. Basically any exercise that
consists of short exertion, high-intensity movement is an anaerobic
exercise.

39. The processes of Aerobic Respiration

40. Glycolysis

41. Citric Acid Cycle (TCA cycle)

42. The Electron Transport Chain

43. Uses of anaerobic respiration

44. Carbohydrates
A carbohydrate is a biomolecule consisting of carbon, hydrogen and
oxygen atoms, usually with a hydrogen–oxygen atom ratio of 2:1. The
empirical formula C . This formula holds true for monosaccharidesₘₙ
Ex: Whole-grain products such as brown rice, whole-grain pasta,
beans, whole wheat bread, whole oats, buckwheat, millet, whole rye,
whole-grain barley and whole-grain corn are considered good
carbohydrates.
Carbohydrates have six major functions within the body:
 Providing energy and regulation of blood glucose.
 Sparing the use of proteins for energy.
 Breakdown of fatty acids and preventing ketosis.
 Biological recognition processes.
 Flavor and Sweeteners.
 Dietary fiber.

45. Types of Carbohydrates

46. Proteins are large biomolecules consisting of one or more long chains
of amino acids (organic compounds containing amine (-NH2) and
carboxyl (-COOH) functional groups, along with a side chain (R group)
specific to each amino acid.). Proteins differ from one another primarily
in their sequence of amino acids.
Functions of proteins
Catalysing metabolic reactions, DNA replication, Response to stimuli,
and transporting molecules from one location to another.
Proteins

47. Primary structure: it is the amino acid sequence and forms a protein which is
a polyamide.
Secondary structure: regularly repeating local structures stabilized
by hydrogen bonds.
They are of 3 types: α-helix, β-sheet and turns. Because secondary structures
are local, many regions of different secondary structure can be present in the
same protein molecule.
Tertiary structure: It is the spatial relationship of the secondary structures to
one another and forms the overall shape of a single protein molecule. It is
generally stabilized by nonlocal interactions by formation of hydrophobic
core, salt bridges, hydrogen bonds, disulfide bonds, and posttranslational
modifications. The term "tertiary structure" is often used as synonymous
with the term fold. The tertiary structure is what controls the basic function
of the protein.
Quaternary structure: the structure formed by several protein molecules
(polypeptide chains), usually called protein subunits.

49. Nucleic acids are complex organic substance present in living
cells, especially DNA or RNA, whose molecules consist of many
nucleotides linked in a long chain.
Nucleic Acids

50. Structure of DNA

51. Lipids as key Biological Molecules

52. Classification of Lipids

53. Structure of Lipids