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THE CELL STRUCTURE & ORGANELLES
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PLASMA MEMBRANE
CYTOPLASM
NUCLEUS
ENDOPLASMIC RETICULUM
RIBOSOMES
GOLGI COMPLEX
MITOCHONDRIA
LYSOSOMES
MICROFILAMENTS & MICROTUBULES
MICROVILLI
CILIA & FLAGELLA
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• PLASMA MEMBRANE:• STRUCTURE:• MADE OF TWO PHOSPHOLIPID BILAYERS,
CHOLESTEROL & PROTEINS MOLECULES.
• FUNCTIONS:• SELECTIVELY CONTROLS MOVEMENT OF
MATERIALS INTO & OUT OF THE CELL.
• CONTAIN RECEPTORS FOR HORMONES
AND ENZYMES.
• CYTOPLASM:- IS THE GEL-LIKE FLUID
INSIDE THE CELL SURROUNDING THE
ORGANELLES
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THE PLASMA MEMBRANE
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• THE NUCLEUS:• THE LARGEST ORGANELLE IN THE CELL.
• SURROUNDED BY THE NUCLEUS ENVELOPE.
• CONTAIN 23 PAIRS OF CHROMOSOMES MADE
OF DNA AND PROTEINS.
• CHROMOSOMES CONTROL CELL FUNCTIONS
AND CELL DIVISION.
• THE RIBOSOMES:• TINY ORGANELLES MADE OF RNA & PROTEIN
• ARE THE SITES FOR PROTEINS SYNTHESIS.
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THE NUCLEUS
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THE ENDOPLASMIC RETICULUM
• A LARGE MEMBRANOUS STRUCTURE.
• ROUGH ENDOPLASMIC RETICULUM:• HAS MANY RIBOSOMES ON ITS SURFACE.
• IT IS THE SITE FOR PROTEIN SYNTHESIS.
• SMOOTH ENDOPLASMIC RETICULUM:• HAS NO RIBOSOMES ON ITS SURFACE.
• IT IS THE SITE FOR LIPID SYNTHESIS.
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ROUGH & SMOOTH
ENDOPLASMIC RETICULUM
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• THE GOLGI COMPLEX:• FLATTENED MEMBRANOUS SACS.
• PROCESS SYNTHESIZED SUBSTANCES AND
PACKAGE THEM INTO SECRETORY VESICLES.
• ALSO MAKE THE LYSOSOMES.
• THE LYSOSOMES:• SMALL VESICLES CONTAINING POWERFULL
DIGESTIVE ENZYMES TO DIGEST BACTERIA
AND DAMAGED CELLS.
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Figure 03.05
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• THE MITOCHONDRIA:• IS THE “POWERHOUSE” OF THE CELL.
• IT USES NUTRIENTS ENERGY TO MAKE ATP.
• ATP IS THE ENERGY SOURCE FOR ALL
CELLULAR FUNCTIONS.
• THE MICROVILLI:• ARE OUTER EXTENSIONS OF THE PLASMA
MEMBRANE.
• THEY INCREASE THE CELL SURFACE AREA.
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Figure 03.06a
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Figure 03.06b
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• THE CYTOSKELETON:• IS MADE OF THE MICROTUBULES AND THE
MICROFILAMENTS.
• THEY PROVIDE SUPPORT FOR THE CELL AND
ENABLE ORGANELLES OR CELL MOVEMENT.
• CILIA & FLAGELLA:• ARE SMALL HAIRLIKE PROGECTIONS FROM
THE CELL PLASMA MEMBRANE.
• THEY HAVE WAVE-LIKE MOTION FOR CELL
MOVEMENT.
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Figure 03.07
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TRANSPORT THROUGH THE
PLASMA MEMBRANE
• PASSIVE TRANSPORT:• IN PASSIVE TRANSPORT SUBSTANCES MOVE
ACROSS THE CELL MEMBRANE WITHOUT
ASSISTANCE OR USE OF ENERGY BY CELLS.
• ACTIVE TRANSPORT:• IN ACTIVE TRANSPORT THE CELL USES ATP
ENERGY TO MOVE SUBSTANCES ACROSS THE
CELL MEMBRANE.
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PASSIVE TRANSPORT
(1) DIFFUSION:• IS MOVEMENT OF MOLECULES FROM AN AREA
OF HIGHER CONCENTRATION TO AN AREA OF
LOWER CONCENTRATION DOWN A
CONCENTRATION GRADIENT.
• IT RESULT FROM RANDOM CONSTANT
MOVEMENT OF MOLECULES IN LIQUIDS OR
GASES IN LIVING & NONLIVING SYSTEMS.
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DIFFUSION
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PASSIVE TRANSPORT
(2) OSMOSIS:• IS THE DIFFUSIOPN OF WATER THROUGH A
SELECTIVELY PERMIABLE MEMBRANE.
• SOLUTIONS ARE HYPERTONIC, HYPOTONIC
OR ISOTONIC WHEN COMPARED TOGETHER
FOR THEIR EFFECT ON A RED BLOOD CELL.
(3) FILTERATION:• IS THE FORCING OF SMALL MOLECULES IN A
SOLUTION THROUGH A MEMBRANE BY THE
HYDROSTATIC PRESSURE OF THE FLUID.
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OSMOSIS
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FILTERATION
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ACTIVE TRANSPORT
(1) CARRIER PROTEINS:• ARE CELL MEMBRANE PROTEINS THAT BIND
MOLECULES AND TRANSPORT THEM ACROSS
THE CELL MEMBRANE TO THE OTHER SIDE.
(2) ENDOCYTOSIS & EXOCYTOSIS:• IS THE ENGULFMENT OF LARGE MOLECULES
TO TAKE THEM INSIDE OR EXPEL THEM
OUTSIDE THE CELL
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CARRIER PROTEIN ACTIVE
TRANSPORT
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ENDOCYTOSIS
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CELLULAR RESPIRATION
• IS THE PROCESS THAT BREAKS DOWN THE
NUTRIENTS TO RELEASE THEIR ENERGY AND
USE IT FOR MAKING ATP.
(1) AEROBIC RESPIRATION:• REQUIRES THE USE OF OXYGEN AND IS
ESSENTIAL FOR LIFE.
• OCCURS ONLY IN THE MITOCHONDRIA.
(2) ANAEROBIC RESPIRATION:• DOES NOT REQUIRE OXYGEN.
• OCCURS IN THE CYTOPLASM.
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Figure 03.17
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PROTEIN SYNTHESIS
• IS CONTROLLED BY DNA & CARRIED OUT BY
RNA AND THE RIBOSOMES.
• DNA:• IS A DOUBLE HELIX MADE OF TWO COILED
STRANDS OF NUCLEOTIDES HELD TOGETHER
BY HYDROGEN BONDS FORMED BETWEEN
THE ORGANIC BASES.
• THE SEQUENCE OF ORGANIC BASES IN DNA
FORM THE GENATIC CODE THAT CONTROLS
CELL FUNCTIONS AND DETERMINE ALL THE
HEREDITARY TRAITS.
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DNA
STRAND
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PROTEIN SYNTHESIS
• RNA:(1) MESSENGER RNA {mRNA}:• CARRY THE GENETIC INFORMATION FROM
DNA TO THE RIBOSOMES.
(2) RIBOSOMAL RNA {rRNA}:• IS THE RNA THAT IS FOUND IN RIBOSOMES.
(3) TRANSFER RNA {tRNA}:• CARRY AMINO ACIDS FROM THE CELL
CYTOPLASM INTO THE RIBOSOMES.
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PROTEIN SYNTHESIS
• TRANSCRIPTION:• IS COPYING THE ENCODED INFORMATION
FROM THE SEQUENCE OF BASES IN DNA INTO
A SEQUENCE OF BASES IN mRNA.
• TRANSLATION:• THE INCODED INFORMATION FROM THE
SEQUENCE OF BASES IN mRNA IS USED BY
THE RIBOSOMES TO PRODUCE A SPECIFIC
SEQUENCE OF AMINO ACIDS TO FORM THE
PROTEIN.
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Figure 03.19
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THE CELL CYCLE
• INTERPHASE:• IS THE TIME WHEN THE CELL IS NOT
INVOLVED IN ANY TYPE OF CELL DIVISION.
• MITOTIC CELL DIVISION:• IS THE REPLICATION OF A PARENT CELL TO
PRODUCE TWO IDENTICAL DAUGHTER CELLS
WITH 46 CHROMOSOMES IN EACH ONE.
• MEIOTIC CELL DIVISION:• IS THE REPLICATION OF A PARENT CELL TO
PRODUCE FOUR DAUGHTER CELLS WITH 23
CHROMOSOMES IN EACH ONE.
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Figure 03.20
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DNA REPLICATION DURING
INTERPHASE
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MITOTIC CELL DIVISION
PHASES
• PROPHASE:- REPLICATED CHROMOSOMES
BECOME ROD - SHAPED
• METAPHASE:- REPLICATED CHROMOSOMES
LINE UP AT THE MIDLINE
• ANAPHASE:- REPLICATED CHROMOSOMES
SEPARATE INTO TWO SETS
• TELOPHASE:- A NUCLEAR ENVELOPE FORM
AROUND EACH SET OF CHROMOSOMES
AND CYTOKINESIS BEGIN
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PROPHASE
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METAPHASE
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ANAPHASE
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TELOPHASE
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