Cell Structures and Their Functions

Cell Structure Highly Organized Highly Organized. Specialized structures called organelles in a jelly like substance called cytoplasm Amount and type of organelles is related to function Amount and type of organelles is related to function

Functions of the Cell Basic Unit of Life -smallest part that still retains characteristics of life Basic Unit of Life -smallest part that still retains characteristics of life Protection And Support – cells secrete substances that provide Protection And Support – cells secrete substances that provide Movement- occurs because of molecules that are located in specific cells e.g. muscle cells Movement- occurs because of molecules that are located in specific cells e.g. muscle cells Communication-cells receive information that allow them to communicate with each other eg nerves cell tells muscle cells to contract Communication-cells receive information that allow them to communicate with each other eg nerves cell tells muscle cells to contract Cell metabolism and energy release- all the chemical reactions that occur within the cell Cell metabolism and energy release- all the chemical reactions that occur within the cell Inheritance – each cell contains a copy of the genetic information of the individual Inheritance – each cell contains a copy of the genetic information of the individual

The Organelles The Nucleus The Nucleus Nucleoli and Ribosomes Nucleoli and Ribosomes Rough and Smooth Endoplasmic Reticulum Rough and Smooth Endoplasmic Reticulum The Golgi Apparatus The Golgi Apparatus Secretory Vesicles Secretory Vesicles Lysosomes and Peroxiisomes Lysosomes and Peroxiisomes Mitochondria Mitochondria Cytoskeleton Cytoskeleton Centrioles Centrioles Cilia, Flagella and Microvilli Cilia, Flagella and Microvilli The Cell Membrane The Cell Membrane

Cell Membrane Phospholipid Bilayer Phospholipid Bilayer Protection and Transport Protection and Transport Types of Transport Types of Transport Active ( requires ATP) Active ( requires ATP) Passive Passive

Nucleus Contains the genetic material of cell (DNA) Contains the genetic material of cell (DNA) Located near the center of the cell Located near the center of the cell Some cells lose their nucleus as they mature, some have more than one nucleus bone cells Some cells lose their nucleus as they mature, some have more than one nucleus bone cells Nuclear envelop (outer and inner membranes and nuclear pores) Nuclear envelop (outer and inner membranes and nuclear pores) Contains loosely coiled fibers called chromatin consisting of DNA When a cell divides the chromatin becomes more tightly coiled to form the 23 pairs of chromosomes Contains loosely coiled fibers called chromatin consisting of DNA When a cell divides the chromatin becomes more tightly coiled to form the 23 pairs of chromosomes

Nucleoli and Ribosomes Nucleoli- are rounded dense well defined nuclear bodies with no surrounding membranes Nucleoli- are rounded dense well defined nuclear bodies with no surrounding membranes Ribosome's- are the organelles where proteins are produced Ribosome's- are the organelles where proteins are produced -may be free -attached to the endoplasmic reticulum -may be free -attached to the endoplasmic reticulum -made in the nucleus -made in the nucleus

Smooth and Rough Endoplasmic Reticulum The ER is a series of membranes forming sacs and tubules that extends from the outer nuclear membrane into the cytoplasm The ER is a series of membranes forming sacs and tubules that extends from the outer nuclear membrane into the cytoplasm Rough ER – has ribosomes attached indicting that it is synthesizing large amounts of protein for export from the cell Rough ER – has ribosomes attached indicting that it is synthesizing large amounts of protein for export from the cell

Protein Synthesis Transcription Transcription Translation Translation

RNA mRNA mRNA t RNA t RNA r RNA r RNA

The Golgi Apparatus Golgi Apparatus- closely packed stacks of curved membrane –bound sacs. Golgi Apparatus- closely packed stacks of curved membrane –bound sacs. Its function is to collect modify, package and distribute proteins and lipids manufactured by the Endoplasmic Reticulum Its function is to collect modify, package and distribute proteins and lipids manufactured by the Endoplasmic Reticulum May also chemically modify the proteins by attaching carbohydrates or lipids to them May also chemically modify the proteins by attaching carbohydrates or lipids to them Found in great number in cells tat make a great deal of protein e.g. pancreas Found in great number in cells tat make a great deal of protein e.g. pancreas

Secretory Vesicles a vesicle is a small membrane bound sac that transports or stores materials within cells a vesicle is a small membrane bound sac that transports or stores materials within cells Secretory vesicles – pinch off from the golgi apparatus and move to the surface of the cell. Their membranes fuse with the cell membrane and release contents to the exterior of the cell Secretory vesicles – pinch off from the golgi apparatus and move to the surface of the cell. Their membranes fuse with the cell membrane and release contents to the exterior of the cell

Lysosomes and Peroximes Lysosomes are membrane bound vesicles formed from the golgi apparatus. They contain a variety of enzymes that functions as intracellular digestive systems Lysosomes are membrane bound vesicles formed from the golgi apparatus. They contain a variety of enzymes that functions as intracellular digestive systems Peroxisomes small membrane bound vesicles containing enzymes that break down fatty acids, amino acids and hydrogen peroxide. Peroxisomes small membrane bound vesicles containing enzymes that break down fatty acids, amino acids and hydrogen peroxide.

Mitochondria Mitochondria- small bean shaped, long threadlike organelles that has inner and outer membranes separated by a space. The outer membranes have a smooth corebut the inner membrane has numerous folds called cristae Mitochondria- small bean shaped, long threadlike organelles that has inner and outer membranes separated by a space. The outer membranes have a smooth corebut the inner membrane has numerous folds called cristae Site of ATP production within the cells and carry out aerobic respiration Site of ATP production within the cells and carry out aerobic respiration muscle cells muscle cells

Cytoskeleton Cytoskeleton- consists of proteins that support the cell, hold organelles in place and enable the cell to change shape. Cytoskeleton- consists of proteins that support the cell, hold organelles in place and enable the cell to change shape.

Microtubules, Microfilaments and Intermediate filaments Microtubules Microtubules Microfilaments Microfilaments Intermediate filaments Intermediate filaments

Centrioles Centosome- a specialized zone of cytoplasm close to the nucleus that is the center of microtubule formation. Centosome- a specialized zone of cytoplasm close to the nucleus that is the center of microtubule formation. It contains the centrioles normally oriented perpendicular to each other It contains the centrioles normally oriented perpendicular to each other Shaped like a cylinder and has nine triplets, each consisting of three parallel microtubules joined together. Shaped like a cylinder and has nine triplets, each consisting of three parallel microtubules joined together.

Protein Synthesis DNA in nucleolus is Transcribed to MRNA DNA in nucleolus is Transcribed to MRNA MRNA is translated at the level of the ribosomal subunits where the codons are read and translated into amino acids MRNA is translated at the level of the ribosomal subunits where the codons are read and translated into amino acids The amino acids form peptide bonds to create one larger protein The amino acids form peptide bonds to create one larger protein

DNA and RNA DNA has 4 nitrogenous bases : adenine, guanine, cytosine and thiamine plus the sugar deoxyribose DNA has 4 nitrogenous bases : adenine, guanine, cytosine and thiamine plus the sugar deoxyribose RNA has 4 nitrogenous bases : adenine, guanine, cytosine and uracil plus the sugar ribose. RNA has 4 nitrogenous bases : adenine, guanine, cytosine and uracil plus the sugar ribose. Remember there are 64 sets of codons (a codon is 3 base pairs) that encode for only 20 amino acids Remember there are 64 sets of codons (a codon is 3 base pairs) that encode for only 20 amino acids

Fate of the Cell Divides ( Mitosis and Meiosis) Divides ( Mitosis and Meiosis) Differentiates Differentiates Apoptosis Apoptosis Tumor ( Benign or Malignant) Tumor ( Benign or Malignant) Ages Ages Death * The Cloning of Cells Death * The Cloning of Cells

Mitosis all cells except sex cell(meiosis) Mitosis all cells except sex cell(meiosis) Interphase Interphase Prophase Prophase Metaphase Metaphase Anaphase Anaphase Telophase Telophase Cytokinesis Cytokinesis Cell Division

Differentiation We learned that through mitosis all cells in an individuals body contain the same amount and type of DNA We learned that through mitosis all cells in an individuals body contain the same amount and type of DNA So, even though the genetic material is the same, why is it that cells do not look and function the same way, example of diverse cells in text So, even though the genetic material is the same, why is it that cells do not look and function the same way, example of diverse cells in text The process by which a cell develop special structure and functions is called DIFFERENTIATION. The process by which a cell develop special structure and functions is called DIFFERENTIATION.

What happens during differentiation? DNA is either active or inactive pending in the cell type via the selective activation of certain portions of the DNA DNA is either active or inactive pending in the cell type via the selective activation of certain portions of the DNA As they mature and differentiate the rate eventually slows and stops As they mature and differentiate the rate eventually slows and stops

Apoptosis Programmed cell death is a normal process by which cell numbers within various tissues are adjusted and controlled. During development any extra tissue s removed, such as the webs between the toes and the fingers. Programmed cell death is a normal process by which cell numbers within various tissues are adjusted and controlled. During development any extra tissue s removed, such as the webs between the toes and the fingers.

Cellular Aging Cellular Clock after a certain time or number of cell divisions cell death occurs in a given line Cellular Clock after a certain time or number of cell divisions cell death occurs in a given line Death genes turn on causing cells to deteriorate Death genes turn on causing cells to deteriorate DNA damage over years DNA damage over years Free Radicals (unpaired electrons) cause direct damage via mutations Free Radicals (unpaired electrons) cause direct damage via mutations Mitochondrial damage causes a loss of energy needed to maintain cell life Mitochondrial damage causes a loss of energy needed to maintain cell life

Cellular Tumor Transformation Tumor- any swelling that occurs within the body Tumor- any swelling that occurs within the body malignant- spreads rapidly, can get large malignant- spreads rapidly, can get large benign- can get large benign- can get large

Cancer Cancers are malignant spreading tumors Can spread via the lymphatic, hematologic, or local expansion routes Growth becomes out of control and the cancer breaks away from normal control Occur as a result of viruses, toxins Treatment in the form of Chemotherapy Immunotherapy Radiotherapy ‘ Starvation to cancer

Cloning A nucleus removed from a differentiated cell can be transferred to an oocyte with the nucleus removed and a complete frog can be formed A nucleus removed from a differentiated cell can be transferred to an oocyte with the nucleus removed and a complete frog can be formed