Biology exam preparation
Physiological foundations of selected life processes
1. The Cell
1.1 Definition, structure and basic functions of a cell
1.2 Cellular organelles and their functions:
• Nucleus and nucleolus
• Cytoplasm
• Mitochondria
• Ribosomes
2. The Plasma Membrane
2.1 Structure and basic composition of the plasma membrane
2.2 Components of the plasma membrane:
• Phospholipid bilayer
• Cholesterol
• Glycolipids and carbohydrates
• Membrane proteins
2.3 The difference between liposomes and micelles
2.4 Structure and types membrane proteins
2.5 Cholesterol in the membrane:
• Chemical structure and amphipathic nature
• Role in maintaining membrane fluidity and stability
2.6 Models of the plasma membrane:
• Davson–Danielli model – structure and limitations
• Fluid Mosaic Model – dynamic properties and updated understanding
1
,Biology exam preparation
1.1 The cell
1. The structure of a cell:
Definition of a cell:
A cell is defined as the smallest basic unit of life that is responsible for all life processes.
The difference between plant cells and animal cells:
1. Similarities:
-Both animal and plant cells have mitochondria
-Both plant and animal cells have vacuoles (a plant cell contains a large, single vacuole, which is used
to store and maintain cell shape. In contrast, animal cells have many smaller vacuoles)
2. Differences:
-The plant cells have a cell wall surrounding the cell membrane, while the animal cells have only one
cell membrane
-In the plant cells, there is a larger vacuole in comparison to the animal cells
-Due to the presence of a cell wall, the cells in the plants are more structured
-Plant cells contain chloroplasts, which are used in photosynthesis to create energy for the plant
The role of the cell in the human body:
1. Growth:
In complex organisms such as humans, the tissues grow by simple multiplication of cells. Hence, cells
are responsible for the growth of the organism which takes place via a process of mitosis.
2. Transport:
Cells import nutrients used in various chemical processes inside the body. In addition, this process
creates waste products that are then excreted by the cells.
3. Energy production:
Organisms need energy to perform different chemical reactions. In plants, the energy comes from
the process of photosynthesis while in the animals the energy comes via respiration.
4. Metabolism:
Cells are responsible for metabolism, including all the chemical reactions that take place inside an
organism to keep it alive.
5. Reproduction:
A cell helps in reproduction by the processes of mitosis (in more evolved organisms) and meiosis.
2
, Biology exam preparation
2. Describing the different parts and functions of a cell:
Nucleus and nucleolus:
The nucleus is a large membrane-bounded organelle located near the center of the cell and contains
most of the cell's genetic material in the form of chromosomes. In addition, the nucleus acts as the
control center of the cell, coordinating many important cellular activities such as protein synthesis,
cell division, growth, and a host of other important functions. Inside the cell's nucleus is the
nucleolus, a spherical structure whose primary function is to produce and assemble the cell's
ribosomes.
Cell Membrane:
The plasma membrane, acts as a cell's surrounding barrier, that is composed primarily of fat-based
molecules called phospholipids. This framework is arranged in two layers called the phospholipid
bilayer, with a hydrophobic, non-polar interior representing the fatty acid tails and a hydrophilic,
polar outer head. Together, they separate the interior of the cell from the outside environment and
are responsible for various functions, such as regulating the transport of materials or protecting the
cell from its environment.
Cytoplasm:
Cytoplasm is the gelatinous liquid that fills the inside of a cell. It is composed of water, salts, and
various organic molecules. In eukaryotes (i.e., cells having a nucleus), the cytoplasm contains all of
the organelles.
Main cytoplasmic organelles:
-Mitochondria:
Mitochondria are membrane-bound cell organelles that generate most of the chemical energy
needed to power the cell's biochemical reactions. Chemical energy produced by the mitochondria is
stored in a small molecule called adenosine triphosphate (ATP).
-Ribosomes:
The ribosome is a cytoplasmic structure that is tiny and spherical in shape. It is composed of protein
and ribonucleic acid (RNA). Ribosomes, together with the cell nucleus, are responsible for the
production of new proteins during the process of protein synthesis.
3
Physiological foundations of selected life processes
1. The Cell
1.1 Definition, structure and basic functions of a cell
1.2 Cellular organelles and their functions:
• Nucleus and nucleolus
• Cytoplasm
• Mitochondria
• Ribosomes
2. The Plasma Membrane
2.1 Structure and basic composition of the plasma membrane
2.2 Components of the plasma membrane:
• Phospholipid bilayer
• Cholesterol
• Glycolipids and carbohydrates
• Membrane proteins
2.3 The difference between liposomes and micelles
2.4 Structure and types membrane proteins
2.5 Cholesterol in the membrane:
• Chemical structure and amphipathic nature
• Role in maintaining membrane fluidity and stability
2.6 Models of the plasma membrane:
• Davson–Danielli model – structure and limitations
• Fluid Mosaic Model – dynamic properties and updated understanding
1
,Biology exam preparation
1.1 The cell
1. The structure of a cell:
Definition of a cell:
A cell is defined as the smallest basic unit of life that is responsible for all life processes.
The difference between plant cells and animal cells:
1. Similarities:
-Both animal and plant cells have mitochondria
-Both plant and animal cells have vacuoles (a plant cell contains a large, single vacuole, which is used
to store and maintain cell shape. In contrast, animal cells have many smaller vacuoles)
2. Differences:
-The plant cells have a cell wall surrounding the cell membrane, while the animal cells have only one
cell membrane
-In the plant cells, there is a larger vacuole in comparison to the animal cells
-Due to the presence of a cell wall, the cells in the plants are more structured
-Plant cells contain chloroplasts, which are used in photosynthesis to create energy for the plant
The role of the cell in the human body:
1. Growth:
In complex organisms such as humans, the tissues grow by simple multiplication of cells. Hence, cells
are responsible for the growth of the organism which takes place via a process of mitosis.
2. Transport:
Cells import nutrients used in various chemical processes inside the body. In addition, this process
creates waste products that are then excreted by the cells.
3. Energy production:
Organisms need energy to perform different chemical reactions. In plants, the energy comes from
the process of photosynthesis while in the animals the energy comes via respiration.
4. Metabolism:
Cells are responsible for metabolism, including all the chemical reactions that take place inside an
organism to keep it alive.
5. Reproduction:
A cell helps in reproduction by the processes of mitosis (in more evolved organisms) and meiosis.
2
, Biology exam preparation
2. Describing the different parts and functions of a cell:
Nucleus and nucleolus:
The nucleus is a large membrane-bounded organelle located near the center of the cell and contains
most of the cell's genetic material in the form of chromosomes. In addition, the nucleus acts as the
control center of the cell, coordinating many important cellular activities such as protein synthesis,
cell division, growth, and a host of other important functions. Inside the cell's nucleus is the
nucleolus, a spherical structure whose primary function is to produce and assemble the cell's
ribosomes.
Cell Membrane:
The plasma membrane, acts as a cell's surrounding barrier, that is composed primarily of fat-based
molecules called phospholipids. This framework is arranged in two layers called the phospholipid
bilayer, with a hydrophobic, non-polar interior representing the fatty acid tails and a hydrophilic,
polar outer head. Together, they separate the interior of the cell from the outside environment and
are responsible for various functions, such as regulating the transport of materials or protecting the
cell from its environment.
Cytoplasm:
Cytoplasm is the gelatinous liquid that fills the inside of a cell. It is composed of water, salts, and
various organic molecules. In eukaryotes (i.e., cells having a nucleus), the cytoplasm contains all of
the organelles.
Main cytoplasmic organelles:
-Mitochondria:
Mitochondria are membrane-bound cell organelles that generate most of the chemical energy
needed to power the cell's biochemical reactions. Chemical energy produced by the mitochondria is
stored in a small molecule called adenosine triphosphate (ATP).
-Ribosomes:
The ribosome is a cytoplasmic structure that is tiny and spherical in shape. It is composed of protein
and ribonucleic acid (RNA). Ribosomes, together with the cell nucleus, are responsible for the
production of new proteins during the process of protein synthesis.
3
