IB Biology
Chapter 1 Cell Biology (page 1-65)
Cell theory:Every living organism is made up of cells.
Unicellular organisms:They consist of a single cell and perform all the functions of life
within said cell.
Limitations on cell size:The surface/volume ratio is very important as a limiting factor for
cell size:
● The metabolic rate of the cell is proportional to its volume. This occurs in the
cytoplasm.
● Substances enter and leave the cell through the plasma membrane, the rate of which
depends on the cell surface area.
● If the ratio is too small, substances will not enter as quickly and waste will
accumulate. They can also overheat because the metabolism generates more heat
faster than it is dissipated.
Multicellular organisms:They have properties that result from the interaction between their
cellular components. They are made up of a mass of fused cells.
Gene expression and cell differentiation:Differentiation involves the expression of specific
genes in the cell's genome and not others.
Stem cells:Their ability to divide and differentiate along different routes is necessary in
embryonic development.
● They can divide again and again to produce large numbers of new cells.
● They are not totally differentiated.
1.2 Ultrastructure of cells (18)
Prokaryotic cell structure:
● simple, without compartmentalization.
● It has no core
● Binary fission: single chrom-
osoma replicates and its two copies
They go to opposite ends of the cell.
Inm. cyto division occurs plasma
Structure of the eukaryotic cell:compartmentalized cell structure.
Core It contains chromosomes, which consist of DNA associated with
proteins (histones). The uncondensed chromosomes in the nucleus are
chromatin. In the nucleus, DNA is replicated and transcribed to form
mRNA, exported to the cytoplasm through the nuclear pores.
reticle Series of flattened membrane sacs called cisternae. The ribosomes are
Endo- stuck together.
plasmaticRough Its main function is to synthesize proteins for secretion from the cell.
(REr) These pass into their cisternae, and are transported by vesicles that
separate and move to the Golgi apparatus.
, Device Same formation as REr, but longer cisternae and without attached
of ribosomes, but with vesicles around them. This processes proteins, most
Golgi of which are then transported by vesicles to the plasma membrane for
secretion.
Seed- They are formed from Golgi vesicles, they have a single membrane. The
soma digestive enzymes they contain can be used to break down food ingested
in the bladder, or break down organelles in the cell.
Myth Surrounded by a double membrane. Produces ATP for cells by aerobic
condria respiration. Fats are digested here if they are used as a source of energy
for the cell.
Ribosomes They are formed in the nucleolus. They synthesize proteins, releasing
free them for use in the cytoplasm.
Chlorine Surrounded by double membrane. Produces glucose and other organic
plastic compounds for photosynthesis.
Empty Some animals digest food inside vacuoles, and some single-celled
waves and organisms use them to expel excess water. Vesicles are small vacuoles
vesicles used to transport materials.
Microtubules Microtubules have several functions, such as moving chromosomes
and centrioles during cell division. Centrioles form an anchoring point for
microtubules during cell division.
Cilia and They are means of displacement, and cilia can also be used to generate
flagella current in the fluid surrounding the cell.
1.3 Structure of membranes (page 27)
Phospholipid bilayers:Phospholipids form them in water due to the amphipathic properties
(hydrophilic end and hydrophobic end) of the phospholipid molecules.
● Hydrophilic end: phosphate group
● Hydrophobic end: two hydrocarbon chains
● They are stable structures and form the basis of all cell membranes.
● Its main function. It's forming a barrier that doesn't easily pass through ions or mol.
hydrophilic
, Cholesterol in the membranes:It reduces the fluidity of the membrane and its permeability
to some solutes. It is hydrophobic with a hydrophilic tip.
1.4 Membrane transport (36)
Endocytosis:Introduction of materials into the
cell. An invagination of a small part of the
membrane occurs, which ends up detaching.
Proteins are responsible for this process, using
energy in the form of ATP.
Movement of vesicles in cells:They facilitate the
movement of materials within the cell.
Exocytosis:A vesicle fuses with the membrane,
leaving its contents outside, that is, outside the
cell.
Methods of movement of particles through the membrane
● Simple diffusion: It is a movement along the
concentration gradient, that is, it moves from the upper
concentration zone to the lower one. Living organisms do
not use it for diffusion (passive process). In the membrane
it is the passage of particles between the phospholipids of
the membrane.
● Facilitated dissemination:Ions and other particles that do not pass through
phospholipids have their own channel, which are holes whose walls are made of
proteins. These channels help particles pass through the membrane (higher
concentration to lower). Only one type of particle can pass through it.
● Osmosis:It is due to differences in the concentration of
substances dissolved in the water (from a dilute solution to
a more concentrated solution). This net movement uses no
energy.
● Active transport:substances absorbed or expelled
towards the highest concentration gradient. This type of transport uses ATP. This
transport is carried out by pump proteins.
CELLS CAN ONLY BE FORMED BY DIVISION OF PRE-EXISTING CELLS
1.6 Cell division (page 55)
Mitosis: division of the nucleus into two genetically identical children. Its phases:
Prophase Chromosomes coil repeatedly (supercoiling). He disappears nucleolus
and microtubules grow that join the poles of the cell. At the end of
Chapter 1 Cell Biology (page 1-65)
Cell theory:Every living organism is made up of cells.
Unicellular organisms:They consist of a single cell and perform all the functions of life
within said cell.
Limitations on cell size:The surface/volume ratio is very important as a limiting factor for
cell size:
● The metabolic rate of the cell is proportional to its volume. This occurs in the
cytoplasm.
● Substances enter and leave the cell through the plasma membrane, the rate of which
depends on the cell surface area.
● If the ratio is too small, substances will not enter as quickly and waste will
accumulate. They can also overheat because the metabolism generates more heat
faster than it is dissipated.
Multicellular organisms:They have properties that result from the interaction between their
cellular components. They are made up of a mass of fused cells.
Gene expression and cell differentiation:Differentiation involves the expression of specific
genes in the cell's genome and not others.
Stem cells:Their ability to divide and differentiate along different routes is necessary in
embryonic development.
● They can divide again and again to produce large numbers of new cells.
● They are not totally differentiated.
1.2 Ultrastructure of cells (18)
Prokaryotic cell structure:
● simple, without compartmentalization.
● It has no core
● Binary fission: single chrom-
osoma replicates and its two copies
They go to opposite ends of the cell.
Inm. cyto division occurs plasma
Structure of the eukaryotic cell:compartmentalized cell structure.
Core It contains chromosomes, which consist of DNA associated with
proteins (histones). The uncondensed chromosomes in the nucleus are
chromatin. In the nucleus, DNA is replicated and transcribed to form
mRNA, exported to the cytoplasm through the nuclear pores.
reticle Series of flattened membrane sacs called cisternae. The ribosomes are
Endo- stuck together.
plasmaticRough Its main function is to synthesize proteins for secretion from the cell.
(REr) These pass into their cisternae, and are transported by vesicles that
separate and move to the Golgi apparatus.
, Device Same formation as REr, but longer cisternae and without attached
of ribosomes, but with vesicles around them. This processes proteins, most
Golgi of which are then transported by vesicles to the plasma membrane for
secretion.
Seed- They are formed from Golgi vesicles, they have a single membrane. The
soma digestive enzymes they contain can be used to break down food ingested
in the bladder, or break down organelles in the cell.
Myth Surrounded by a double membrane. Produces ATP for cells by aerobic
condria respiration. Fats are digested here if they are used as a source of energy
for the cell.
Ribosomes They are formed in the nucleolus. They synthesize proteins, releasing
free them for use in the cytoplasm.
Chlorine Surrounded by double membrane. Produces glucose and other organic
plastic compounds for photosynthesis.
Empty Some animals digest food inside vacuoles, and some single-celled
waves and organisms use them to expel excess water. Vesicles are small vacuoles
vesicles used to transport materials.
Microtubules Microtubules have several functions, such as moving chromosomes
and centrioles during cell division. Centrioles form an anchoring point for
microtubules during cell division.
Cilia and They are means of displacement, and cilia can also be used to generate
flagella current in the fluid surrounding the cell.
1.3 Structure of membranes (page 27)
Phospholipid bilayers:Phospholipids form them in water due to the amphipathic properties
(hydrophilic end and hydrophobic end) of the phospholipid molecules.
● Hydrophilic end: phosphate group
● Hydrophobic end: two hydrocarbon chains
● They are stable structures and form the basis of all cell membranes.
● Its main function. It's forming a barrier that doesn't easily pass through ions or mol.
hydrophilic
, Cholesterol in the membranes:It reduces the fluidity of the membrane and its permeability
to some solutes. It is hydrophobic with a hydrophilic tip.
1.4 Membrane transport (36)
Endocytosis:Introduction of materials into the
cell. An invagination of a small part of the
membrane occurs, which ends up detaching.
Proteins are responsible for this process, using
energy in the form of ATP.
Movement of vesicles in cells:They facilitate the
movement of materials within the cell.
Exocytosis:A vesicle fuses with the membrane,
leaving its contents outside, that is, outside the
cell.
Methods of movement of particles through the membrane
● Simple diffusion: It is a movement along the
concentration gradient, that is, it moves from the upper
concentration zone to the lower one. Living organisms do
not use it for diffusion (passive process). In the membrane
it is the passage of particles between the phospholipids of
the membrane.
● Facilitated dissemination:Ions and other particles that do not pass through
phospholipids have their own channel, which are holes whose walls are made of
proteins. These channels help particles pass through the membrane (higher
concentration to lower). Only one type of particle can pass through it.
● Osmosis:It is due to differences in the concentration of
substances dissolved in the water (from a dilute solution to
a more concentrated solution). This net movement uses no
energy.
● Active transport:substances absorbed or expelled
towards the highest concentration gradient. This type of transport uses ATP. This
transport is carried out by pump proteins.
CELLS CAN ONLY BE FORMED BY DIVISION OF PRE-EXISTING CELLS
1.6 Cell division (page 55)
Mitosis: division of the nucleus into two genetically identical children. Its phases:
Prophase Chromosomes coil repeatedly (supercoiling). He disappears nucleolus
and microtubules grow that join the poles of the cell. At the end of
