Download cells - WordPress.com

-
STRUCTURE / FUNCTION / DIVERSITY
DNA
CELL DIVISION (MITOSIS / MEIOSIS)
CELLULAR SPECIALIZATION
- STRUCTURE & FUNCTION OF A
HUMAN CELL
- STRUCTURE & FUNCTION OF DNA
- GENETIC DIVERSITY
• THE CELL IS THE BASIC UNIT OF LIFE
ALL LIVING THINGS MUST BE ABLE TO NOURISH THEMSELVES,
BREATHE, ELIMINATE WASTE, GROW, AND REPRODUCE
STRUCTURE
• 1- CELL MEMBRANE – a flexible barrier that surrounds the cell
content, allowing the cell to interact with its environment
• 2- CYTOPLASM – a gelatinous fluid inside the cell membrane and
outside the nucleus
• 3- NUCLEUS – the cell’s control center (BRAIN OF CELL)
• CELL MEMBRANE –
a) forms a barrier and protects the cell
b) facilitates the absorption of nutrients
c) facilitates the evacuation of waste
• CYTOPLASM –
a) establishes an environment that is hospitable for most cell
activities
b) includes the following parts:
MITOCHONDRIA: produce energy through cellular respiration
GOLGI APPARATUS: stores material produced by the cell and
transports it to the cell membrane and outside the cell
ENDOPLASMIC RETICULUM: produces some of the material necessary
for cell activities. Transports material from one cell to another.
RIBOSOMES: produces some of the material necessary for cell
activities
• CYTOPLASM (cont) –
CYTOSOL: contains cytoplasm
organelles and many dissolved substances
LYSOSOMES: digest certain
nutrients. Decompose and
recycle various cell
constituents
• NUCLEUS –
a) contains and protects individual genetic information
b) controls all cell activities
NUCLEAR MEMBRANE: forms a barrier and protects the nucleus.
Enables certain exchanges with the rest of the cell.
DNA: controls all cell activity. Controls all genetic information.
• DNA: DEOXYRIBONUCLEIC ACID
A very long molecule inside a cells
nucleus which usually appears as long
threads.
A molecule, shaped like a double helix,
located inside the cell nucleus
The molecule looks like a ladder, and
each rung is formed by a single base
pair
• BASE PAIRS – Sequencing constitutes
the individuals or species genome.
Humans have approximately 3 Billion base
pairs. ADENINE (A) – THYMINE (T)
CYTOSINE (C) – GUANINE (G)
• GENOME – the complete set of
genetic information of an individual or species
• GENES – a segment of DNA that contains genetic
information required to carry out a specific job.
25000 genes determine an individual’s specific characteristics
• GENETIC DIVERSITY –
Achieved by all the possible genetic variations of a
particular species. The greater the population, the greater the
genetic diversity.
1 25000
( )
or 1 out of 1.13 x 1015000
4
- MITOSIS
- MEIOSIS
• CELL DIVISION OCCURS FOR THREE REASONS
• 1- TO INCREASE AN ORGANISM’S CELL COUNT, THEREBY
ALLOWING THE ORGANISM TO GROW
• 2- TO REGENERATE DAMAGED OR BROKEN TISSUE
• 3- TO MAKE SEXUAL REPRODUCTION POSSIBLE
• Cell division is a process that is essential to the production of new
cells for the purpose of growth, tissue repair, and sexual
reproduction.
• INTERPHASE – the period when cells are not dividing
• REPLICATION – the final phase of the dividing process where
the DNA duplicates. The old strand breaks apart while a new
(complimentary) strand attaches.
• CHROMOSOMES – DNA strands coil and condense to form
“rod like” structures called Chromosomes. These chromosomes
are shaped like an “X” and are made up of two rods joined
together at the center. Each rod is called a CHROMATID, which
is an exact copy of the other. Chromosomes form pairs. One
part of the chromosome contains genetic material from the
mother, while the other contains genetic material from the father
• CHROMOSOMES (cont) –
There are 23 sets of Chromosomes in the Human Genome.
The first 22 sets are numbered. The 23rd set determines the
individual’s gender (XX = female, XY = male)
• A PROCESS OF CELL DIVISION IN WHICH CELLS MULTIPLY IN
ORDER TO ENSURE GROWTH AND TISSUE REPAIR
• RESULTS IN DIPLOID CELLS (DOUBLES) WHICH POSSESS TWO
SETS OF CHROMOSOMES – ONE FROM FATHER & ONE FROM
MOTHER
• ALL CELLS IN HUMAN BODY ARE DIPLOID EXCEPT SEX CELLS
• Phases of Mitosis
Starts at the end of
Interphase 1- PROPHASE
2- METAPHASE
3- ANAPHASE
4- TELOPHASE
• PHASE 1 – PROPHASE
• INTERPHASE HAS ENDED – Parent cell has grown and
completely replicated its DNA
• DNA strands coil and condense to form chromosomes
• The Nuclear membrane
disappears
• PHASE 2 – METAPHASE
• Chromosomes align at the center of the cell
• PHASE 3 – ANAPHASE
• Chromosomes split at their centers into chromatids
• Chromatids move away from the center; half go to one end of
the cell, the other half go to the other end
• PHASE 4 – TELOPHASE
• A new nuclear membrane forms
• DNA uncoils into separate strands
• Organelles and cytosol are evenly divided
• The cell divides into two daughter cells
• THE PROCESS OF CELL DIVISION IN WHICH MALE AND FEMALE
GAMETES ARE PRODUCED IN ORDER FOR SEXUAL REPRODUCTION
TO TAKE PLACE
• CALLED HAPLOID CELLS BECAUSE THEY ONLY CONTAIN ONE SET
OF CHROMOSOMES (THAT IS ONE SET FROM EACH PAIR).
• MEIOSIS I: PROPHASE I, METAPHASE I, ANAPHASE I, TELOPHASE I
• MEIOSIS II: PROPHASE II, METAPHASE II, ANAPHASE II, TELOPHASE II
• 4 HAPLOID DAUGHTER CELLS ARE PRODUCED AT THE END
• Stages of
Meiosis
1 – Prophase I
2 – Metaphase I
3 – Anaphase I
4 – Telophase I
5 – Prophase II
6 – Metaphase II
7 – Anaphase II
8 – Telophase II
-
TISSUE TYPES
FROM TISSUE TO ORGAN
FROM ORGAN TO TISSUE
• A tissue is a group of similar cells that have a common structure
and function.
• There are four types of tissue:
1.
2.
3.
4.
Epithelial
Connective
Nerve
Muscle
• This tissue covers and
protects organs, both
inside and outside the
body.
• 1) It protects us from the
outside world - skin
• 2) Absorbs – stomach and
intestinal lining (gut)
• 3) Filters – the kidney
• 4) Secretes – forms glands
• 1) Closely attached to each other forming a protective barrier.
• 2) Always has one free (apical) surface open to outside the
body or inside (cavity) an internal organ.
• 3) Has no blood vessels but can soak up nutrients from blood
vessels in connective tissue underneath.
• 4) Can have lots of nerves in it (innervated).
• 5) Very good at regenerating (fixing itself). i.e. sunburn, skinned
knee.
• This tissue binds and supports tissues and organs in the body.
• They protect and provide nutrients.
• Connective Tissue is the most abundant and widely distributed
tissue in the body.
• As tendon and ligaments protects joints and attached muscles to
bone and each other
• Cartilage
• Functions (jobs):
1) provides strength with
flexibility while resisting
wear, i.e. epiglottis,
external ear, larynx
2) cushions and shock
absorbs where bones
meet, i.e. intervertebral
discs, joint capsules
• Bone
• Functions (jobs):
1) provides framework and
strength for body
2) allows movement
3) stores calcium
4) contains blood-forming
cells
• Blood
• Functions (jobs):
1) transports oxygen, carbon dioxide, and nutrients around the
body
2) immune response
• Helps control and guide body activity, enabling the sending and
receiving of messages from the brain to different parts of the
body.
• You can find Nerve tissue in the following areas:
• Nerves
• Spinal cord
• Brain
• Has the ability to contract
and regain its shape.
(similar to a spring)
• Moves blood, food, waste
through body’s organs
• Two types of movement
1.
2.
Voluntarily – moving ones
leg.
Involuntarily – your heart
beating.
1. Skeletal Muscle tissue:
- Attaches muscle to bone.
2. Smooth Muscle tissue:
- This lines the inside of organs
that contract.
- Stomach, bladder, uterus, and
some blood vessels.
3. Cardiac muscle tissue:
- Found only in and around the
heart.
to
• ORGAN: Structure composed of two or more tissue types
performing one or more specific functions.
• Ex. Stomach has epithelial, connective, muscle and nerve tissue.
They work together to store and break down and digest food.
• Other examples: Skin, heart, lungs and brain.
to
• SYSTEM: A group of
organs and tissues
working together to
accomplish a common
function.
• Ex. Stomach works with
the intestine, esophagus
and other organs in the
digestive system.