Download 5. eukaryotic cells. - IES Gabriela Mistral

1 CELLS AND THEIR COMPONENTS.
Embryonic stem cells
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What is the basic unit of life?
How are prokaryotic cells different from eukaryote cells?
Where does photosynthesis and cellular respiration take place?
What are chromosomes made of?
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1. THE CHEMICAL COMPONENTS OF CELLS.
All living things are made of bioelements and biomolecules.
Biomolecules are made of combinations of bioelements and can be
inorganic such as water and mineral salts, and organic biomolecules
such as carbohydrates, lipids, proteins and nucleic acids.
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1. THE CHEMICAL COMPONENTS OF CELLS.
WATER.
Water is the most abundant molecule in living things because of its
physical and chemical properties, such as its ability to dissolve
substances.
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1. THE CHEMICAL COMPONENTS OF CELLS.
MINERAL SALTS.
They are insoluble in water and are useful for forming skeletal
structures. This is true for tricalcium phospate, found in bones, and
calcium carbonate, present in the shells of molluscs.
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1. THE CHEMICAL COMPONENTS OF CELLS.
CARBOHYDRATES.
They are organic biomolecules composed of carbon, hydrogen and
oxygen molecules. There are different types:
•Monosaccharides. They are the simplest carbohydrates. Some, such as
glucose or fructose, provide energy for cells, while others, such as
ribose , form part of nucleic acids.
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1. THE CHEMICAL COMPONENTS OF CELLS.
CARBOHYDRATES.
•Disaccharides are formed by the union of two monosaccharide
molecules (Sucrose, lactose and maltose).
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1. THE CHEMICAL COMPONENTS OF CELLS.
CARBOHYDRATES.
•Polysaccharides consist of thousands of linked monosaccharide
molecules. They store energy (starch) and provide structural support
(cellulose).
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1. THE CHEMICAL COMPONENTS OF CELLS.
LIPIDS.
Lipids are organic biomolecules that are insoluble in water.
They are composed of carbon, hydrogen and oxygen.
Types:
TRIGLYCERIDES, which are formed by a molecule of glycerol
and three fatty acids, and store large amounts of energy for cells.
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1. THE CHEMICAL COMPONENTS OF CELLS.
LIPIDS.
WAXES, which are water-repellent and help control evaporation
and hydration in both plants and animals.
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1. THE CHEMICAL COMPONENTS OF CELLS.
LIPIDS.
PHOSPHOLIPIDS, which contain phosphoric acid. They make up
part of cell membranes.
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1. THE CHEMICAL COMPONENTS OF CELLS.
LIPIDS.
STEROIDS, which are an important group of lipids include
cholesterol, vitamin D and male and female sex hormones.
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ACTIVITIES.
act 1, page 5.
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2. PROTEIN AND NUCLEIC ACIDS.
PROTEINS.
Proteins are a large biomolecules that are made up of
different combinations of 20 molecules called amino acids.
Structure:
The PRIMARY STRUCTURE of proteins is the linear sequence of
amino acids in a single protein molecule.
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2. PROTEIN AND NUCLEIC ACIDS.
PROTEINS.
Structure:
The SECONDARY STRUCTURE refers to the folding of a protein
into regular sub-structures.
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2. PROTEIN AND NUCLEIC ACIDS.
PROTEINS.
Structure:
The TERTIARY STRUCTURE refers to the three-dimensional
arrangement and interaction of all the secondary structures to one
another.
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2. PROTEIN AND NUCLEIC ACIDS.
PROTEINS.
Structure:
The QUATERNARY STRUCTURE. It is characteristic of large
proteins, such as blood haemoglobin,
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2. PROTEIN AND NUCLEIC ACIDS.
PROTEINS.
FUNCTIONS:
Proteins perform many vital roles in the human body, including:
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2. PROTEIN AND NUCLEIC ACIDS.
NUCLEIC ACIDS.
They are large, organic biomolecules, which are formed by the
bonding of smaller molecules called nucleotides.
Each nucleotide consists of three parts: a monosaccharide
molecule (deoxyribose or ribose) a nitrogenous base (Adenine,
guanine, thymine cytosine or uracil) and a phosphoric molecule.
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2. PROTEIN AND NUCLEIC ACIDS.
DNA.
It is a molecule that carries genetic information. This information is
stored in the genes, which are the functional units of DNA.
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2. PROTEIN AND NUCLEIC ACIDS.
DNA.
A DNA molecule has the following characteristics:
1) Its nucleotides are composed of deoxyribose, phophoric acid
and one of the following bases: adenine, guanine, cytosine or
thymine. It does not contain ribose or uracil.
2) It has 2 strands of nucleotides, which are complementary
because the base pairs are always opposite each other.
3) Double helix.
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2. PROTEIN AND NUCLEIC ACIDS.
DNA.
A DNA molecule has the following characteristics:
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2. PROTEIN AND NUCLEIC ACIDS.
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3. THE STRUCTURE OF PROKARYOTIC AND EUKARYOTIC.
PROKARYOTIC CELLS
They are smaller and less complex. Bacteria, cyanobacteria and
archaea are prokaryotes. The most important characteristics of
prokaryotic cells are the following:
1) They don´t have a nucleus, consequently their genetic material
is free in the cytoplasm. They can also have plasmids, which are
small DNA fragments.
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3. THE STRUCTURE OF PROKARYOTIC AND EUKARYOTIC.
PROKARYOTIC CELLS:
2) They have a cell membrane. They can have other types of
membranes such as cell wall and capsule.
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3. THE STRUCTURE OF PROKARYOTIC AND EUKARYOTIC.
PROKARYOTIC CELLS:
3) They have ribosomes, where proteins are produced, located in
the cytoplasm
4) Many bacteria have pili and flagella.
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3. THE STRUCTURE OF PROKARYOTIC AND EUKARYOTIC.
EUKARYOTIC CELLS:
They are large and complex, and have membranous organelles.
The genetic material is found in the nucleus. The cell membrane
transports and exchanges molecules between the cell and its
environment. It contains cytosol, cytoskeleton, organelles and
ribosomes.
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Nucleoplasm: liquid similar
to cytoplasm.
Chromatin: genetic
material- DNA and Histones.
Nucleolus: spherical
structure which is involved
in the synthesis of
ribosomes.
Nuclear envelope is made
uo of two membranes and
has pores that allow
molecules to move.
NUCLEUS.
Nucleus: which contains
genetic material, is the
control centre of the cell. It
can be considered a special
type of organelle.
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4. ANIMAL AND PLANT CELLS.
Animal cells. They are very complex and have many internal areas with
different functions.
CELL STRUCTURE.
There are many different types of cells, but they all have the same
THESE ARE THE MAIN PARTS
THEY HAVE IN COMMON:
basic structure.
The membrane is a thin layer that separates the cell from the
external environment. The substances necessary for nutrition can
pass through it into the cell and waste products can pass out of
the cell.
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4. ANIMAL AND PLANT CELLS.
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4. ANIMAL AND PLANT CELLS.
The cytosol is the semi-liquid interior of the cell. It contains
biological molecules that are needed to carry out the biochemical
reactions that keep the cell alive.
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4. ANIMAL AND PLANT CELLS.
The cytoskeleton is a set of protein filaments and microtubules.
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4. ANIMAL AND PLANT CELLS.
The centrioles. They form part of the centrosome. It is
composed of microtubules and they are important during cell
division.
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4. ANIMAL AND PLANT CELLS.
The Genetic material contain the information necessary to
control cellular activity and to give the cell its specific
characteristics.
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4. ANIMAL AND PLANT CELLS.
CELL DIFFERENTIATION. It is the process by which a less
specialised cell becomes more specialised to perform particular
functions.
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4. ANIMAL AND PLANT CELLS.
Plant cells.
-They don´t have centrioles. Instead of the centrosome of animal
cells, plant cells have a microtubule-organising centre (MTOC)
without centrioles.
-They have a cell wall of cellulose. The walls have holes called
plasmodesmata.
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4. ANIMAL AND PLANT CELLS.
Plant cells.
-They have chloroplasts.
-Large vacuoles.
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THE ORIGIN OF EUKARYOTIC CELLS: SYMBIOGENESIS.
The theory of Endosymbiosis explains the origin of chloroplasts
and mitochondria and their double membranes.
This concept postulates that chloroplasts and mitochondria are
the result of years of evolution initiated by the
endocytosis
of
bacteria
and
blue-green
algae.
According to this theory, blue green algae and bacteria
were not digested; they became symbiotic instead.
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THE ORIGIN OF EUKARYOTIC CELLS: SYMBIOGENESIS.
•Mitochondria and chloroplasts are similar in size and morphology
to bacterial prokaryotic cells.
•Mitochondria and chloroplasts divide by binary fission, just as
bacteria do, and not by mitosis as eukaryotes do.
•Mitochondria and chloroplasts have their own DNA and their own
ribosomes.
•Organelle ribosomes are more similar in size to prokaryotic
ribosomes.
•Mitochondria arise from preexisting mitochondria; chloroplasts
arise from preexisting chloroplasts.
•Many antibiotics that kill or inhibit bacteria also inhibit protein
synthesis of these organelles.
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4. TYPES OF CELL.
There is a great variety of cell types. They can be classified according to
their size, shape and complexity.
1)CELL SIZE.
Cells are measured in micrometres. The size of cells varies.
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4. TYPES OF CELL.
There is a great variety of cell types. They can be classified according to
their size, shape and complexity.
2)CELL SHAPE.
Cells can be a variety of shapes which are related to their function. They
can be anything from spherical or star-shaped. Plant cells are
geometrically shaped while animal cells are often irregularly shaped.
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4. TYPES OF CELL.
2)CELL SHAPE.
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4. TYPES OF CELL.
There is a great variety of cell types. They can be classified according to
their size, shape and complexity.
3)CELL COMPLEXITY.
There are two types of cell according to their complexity: prokaryotic
and eukaryotic cells. Prokaryotic cells are simpler than eukaryotic cells.
Only bacteria and Archeae have prokaryotic cells. All other organisms
have eukaryotic cells.
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4. TYPES OF CELL.
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ACTIVITIES.
PAGE 82. 2, 3, 4, 5 .
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5. STRUCTURES AND ORGANELLES IN EUKARYOTIC CELLS
Eukaryotic cells appeared later in the evolution process than prokaryotic
cells. They are more developed cells and as a consequence, have several
advantages over prokaryotic cells.
ORGANELLES are structures that consists of a space that is usually
enclosed by a membrane. They are adapted and specialised to
perform specific functions.
There are two main groups of organelles:organelles with membranes
or without membranes.
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ORGANELLES THAT PROCESS NUTRIENTS. A ORGANELLES WITH
MEMBRANES.
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5. EUKARYOTIC CELLS.
Organelles that process nutrients.
THE ENDOPLASMIC RETICULUM. It made up of a complicated network
of tubes and vesicles. It makes and transports various substances such
as lipids and proteins.
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5. EUKARYOTIC CELLS.
Organelles that process nutrients.
-Rough Endoplasmic reticulum. It has ribosomes which make proteins
and pass them to the Golgi apparatus.
-Smooth endoplasmic reticulum DON´T have ribosomes but produce
fats and eliminate toxins.
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5. EUKARYOTIC CELLS.
Organelles that process nutrients.
THE GOLGIS APPARATUS is an organelle made up of vesicles and
flattened sacs. It takes the substances from the endoplasmic reticulum
which modifies and sends them through the vesicles to be delivered to
other places within the cell.
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5. EUKARYOTIC CELLS.
Organelles that process nutrients.
THE GOLGIS APPARATUS
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5. EUKARYOTIC CELLS.
Organelles that process nutrients.
LYSOSOMES AND PEROXISOMES, are tiny vesicles that contains
enzymes that can digest large molecules. Lysosomes carry out
intracellular digestion and peroxisomes control different oxidation
reactions.
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5. EUKARYOTIC CELLS.
Organelles that process nutrients.
VACUOLES, are structures that store various substances, including
nutrients and water. They are bigger and more numerous in plant cells
than in animal cells and can occupy up to 80% os a plant cell´s total
volume.
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5. EUKARYOTIC CELLS.
MITOCHONDRIA, are tube-shaped with a double membrane. The mitochondrial
matrix contains genetic material, ribosomes and enzymes. Mitochondria are found in
all eukaryotic cells. Mitochondria are the energy provides in eukaryotic cells, using
cellular respiration.
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5. EUKARYOTIC CELLS.
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5. EUKARYOTIC CELLS.
CHLOROPLASTS are organelles with a double membrane. They contain
thylakoids, which contain chlorophyll, the pigment that gives them
their characteristic green colour. Photosynthesis occurs in the
chloroplasts. They convert the radiant energy from the sun into
chemical energy. This is then used to convert inorganic molecules such
as carbon dioxide into organic molecules like glucose.
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ACTIVITIES.
PAGE 75. 15, 16, 17, 18.
Homework.
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B. ORGANELLES WITHOUT MEMBRANES.
Organelles without membranes are
ribosomes,
cytoskeleton,
the
centrosome and cilia and flagella
1) Ribosomes. They are composed of RNAr and proteins. They can be
free in the cytoplasm or in ER. Ribosomes translate mRNA in order to
synthetise proteins.
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B. ORGANELLES WITHOUT MEMBRANES.
2) THE CYTOSKELETON. It is a network of protein, which supports the
cytoplasm and is responsible for cell movement. It is made up of:
-Microfilaments made of actin which participate in muscle contraction
and cytokinesis in cell division.
-Intermediate filaments, which are made up of different proteins and
help maintain cell shape.
-Microtubules. Make up the mitotic spindle, cilia and flagella
.
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Some eukaryotic cells are capable of movement. Movement can be
produced in two different ways:
Using cilia and flagella. Cilia are shorter and more numerous than
flagella.
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5.3 CELLS THAT MOVE.
Some eukaryotic cells are capable of movement. Movement can be
produced in two different ways:
Using cilia and flagella.
Cilia and flagella are organelles that can move. They are formed from
the protein fibres of the cytoskeleton. They are external to the cell.
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CENTROSOME.
Includes two centrioles composed of microtubules. It is resposible for
organising microtubules in animal cells and forming spindles during
cell division.
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DEVELOPMENT OF BASIC COMPETENCES
Page 83.
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