CELLS STRUCTURE / FUNCTION / DIVERSITY DNA CELL DIVISION (MITOSIS / MEIOSIS) CELLULAR SPECIALIZATION

THE HUMAN CELL

THE CELL STRUCTURE & FUNCTION OF A HUMAN CELL STRUCTURE & FUNCTION OF DNA GENETIC DIVERSITY

THE HUMAN CELL - STRUCTURE 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)

THE HUMAN CELL - FUNCTION CELL MEMBRANE – a) forms a barrier and protects the cell b) facilitates the absorption of nutrients c) facilitates the evacuation of waste

THE HUMAN CELL - FUNCTION 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

THE HUMAN CELL - FUNCTION CYTOPLASM (cont) – CYTOSOL: contains cytoplasm organelles and many dissolved substances LYSOSOMES: digest certain nutrients. Decompose and recycle various cell constituents

THE HUMAN CELL - FUNCTION 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 – STRUCTURE & FUNCTION 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

DNA STRUCTURE & FUNCTION 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

( 1 4 ) 25000 or 1 out of 1.13 x 10 15000 GENETIC DIVERSITY Achieved by all the possible genetic variations of a particular species. The greater the population, the greater the genetic diversity. ( 1 4 ) 25000 or 1 out of 1.13 x 10 15000

CELL DIVISION MITOSIS MEIOSIS

CELL DIVISION 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.

CELL DIVISION 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

CELL DIVISION 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)

MITOSIS 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

MITOSIS Phases of Mitosis Starts at the end of Interphase - 1- PROPHASE 2- METAPHASE 3- ANAPHASE 4- TELOPHASE

MITOSIS 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

MITOSIS PHASE 2 – METAPHASE Chromosomes align at the center of the cell

MITOSIS 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

MITOSIS 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

MEIOSIS 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

MEIOSIS 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

CELLULAR SPECIALIZATION TISSUE TYPES FROM TISSUE TO ORGAN FROM ORGAN TO TISSUE

TISSUE TYPES A tissue is a group of similar cells that have a common structure and function. There are four types of tissue: Epithelial Connective Nerve Muscle

1) EPITHELIAL TISSUE 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

CHARACTERISTICS (TRAITS): 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.

2) CONNECTIVE TISSUE 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

1) provides framework and strength for body 2) allows movement 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

3) Nerve Tissue 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

4) Muscle Tissue 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 Voluntarily – moving ones leg. Involuntarily – your heart beating.

Three types of Muscle Tissue Skeletal Muscle tissue: - Attaches muscle to bone. Smooth Muscle tissue: - This lines the inside of organs that contract. - Stomach, bladder, uterus, and some blood vessels. Cardiac muscle tissue: - Found only in and around the heart.

From Tissue Organ 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.

From Organ System 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.