IMMUNOLOGY

Clinical Biochemistry & Immunology provides qualitative and quantitative analysis of biological fluids such as blood, serum or plasma, urine, or tissues for specific chemical constituents or physiologic processes.

The staff of Clinical Biochemistry & Immunology are also engaged in applied research to create new

diagnostic clinical laboratory tests to identify or monitor disease, disease processes, or treatment of

disease. Examples of tests created by laboratories affiliated with Clinical Biochemistry & Immunology

include:

Evaluation of immune factors causing disease

Evaluation of endocrine organ function

Monitoring response to cancer treatment

Assessment of transplant immunosuppression

Evaluation of genetic variation on routine therapies

Assessment of nutritional status

Evaluation of drug and metal toxicity.

SECTION 4-2, PARTS OF THE EUKARYOTIC CELL

Eukaryotic Cells generally contain: a cell membrane, A nucleus, and other organelles.

OBJECTIVES:  Describe the structures, composition, and function of the cell membrane.  Name the major organelles found in a Eukaryotic cell, and describe their function.  Describe the structure and function of the nucleus.  Describe three structures characteristic of plant cells.

THE CELL MEMBRANE

A cell cannot survive if it is totally isolated from its environment. The cell membrane is a complex barrier separating the cell from it's external environment. All cells (prokaryotic and eukaryotic) have a cell membrane.

It is called "selectively permeable" because itregulates what passes into and out of the cell.

Cell Membranes are made mostly of PHOSPHOLIPID MOLECULES. (Phosphate + Lipid).

The phosphateh ead is HYDROPHILIC meaning "WATER LOVING".   Because of its hydrophilic nature, the head of a phospholipid will orient itself so that it is as close as possible to water molecules.

The lipid Tails are HYDROPHOBIC meaning "WATER-FEARING". The hydrophobic tails will tend to orient themselves away from water.

When dropped in water, phospholipids line up on the surface with their phosphate heads sticking into the water and lipid tails pointing up from the surface.

Cells are bathed in an aqueous (watery) environment.  Since the inside of a cell is also an aqueous environment, both sides of the cell membrane are surrounded by water molecules.  These water molecules cause the phospholipids of the cell membrane to form two layers.

MEMBRANE PROTEINS

A variety of protein molecules are found in the cell membrane. They are used to move materials into and out of the cell.

Some are attached to the surface of the cell membrane and are called PERIPHERAL PROTEINS. They are located on both the inside and outside surfaces.

Some are embedded in the lipid bilayer are called

INTEGRAL PROTEINS. Some integral proteins form channels or pores through which certain substances can pass.

Integral Proteins exposed to the Cell's External environment often have Carbohydrates attached to them serve as identification badges that allow cells to recognize each other and may act as Site where viruses or chemical messengers such as hormones can attach.

FLUID MOSAIC MODEL OF CELL MEMBRANES

1. Membranes are FLUID and have the consistency of vegetable oil.

2. The lipids and proteins of the cell membrane are always in motion.

3. Phospholipids are able to drift across the membrane, changing places with their

neighbor.

4.  Proteins in and on the membrane form patterns or mosaics.

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ORGANELLES

CYTOPLASM (SIET-oh-PLAZ-uhm)

Everything between the cell membrane and the nucleus is the cytoplasm. It consists of two main components, cytosol and organelles.

Cytosol is a jellylike mixture that contains mostly water along with proteins, carbohydrates, salts and minerals.

Organelles are structures that work like miniature organs - they carry out specific functions.

MITOCHONDRIA (MET-oh-KAHN-dree-uh)

Mitochondria are found scattered throughout the cytosol, and are relatively large organelles. They are the sites of chemical reactions that transfer energy from Organic compounds to ATP.  Energy contain in food is converted to ATP.

Known as "THE POWERHOUSE" of the cell. They are usually more numerous in cells that have a high energy requirement. For example, your muscle cells contain a large number of mitochondria.

Mitochondria are surrounded by TWO Membranes. (Figure 4-8) The smooth outer membrane serves as a boundary between the mitochondria and the cytosol. The inner membrane has many long folds, known as CRISTAE (KRIS-tee).   The cristae greatly increase the surface area of the inner membrane, providing more space for chemical reactions to occur.

Mitochondria have their own DNA, and new mitochondria arise only when existing ones grow and divide.

RIBOSOMES (RIE-buh-SOHMZ)

Unlike most other organelles, ribosomes are not surrounded by a membrane. They are the site of PROTEIN SYNTHESIS (Production or Construction) in a cell.

They are Most Numerous Organelles in almost all cells.

Some are free in the cytoplasm; others line the membranes of rough endoplasmic reticulum.

ENDOPLASMIC RETICULUM (ER) (EN-doh-PLAZ-mik  ri-TIK-yuh-luhm)

The ER is a system of membranous tubules and sacs.

It functions primarily as a path along which molecules move from one part of the cell to another. It transports materials through the cell.

The amount of ER inside a cell fluctuates, depending on the cell's activity.

Poisons, waste, and other toxic chemicals are made harmless.

ER can be rough or smooth:

    ROUGH ER is studded with RIBOSOMES and processes PROTEINS to be exported from the cell.

    SMOOTH ER is NOT Coveredwith RIBOSOMES and processes LIPIDS and CARBOHYDRATES. The Smooth ER is involved in the synthesis of steroids in gland cells, the regulation of calcium levels in muscle cells, and the breakdown of toxic substances by liver cells.

GOLGI APPARATUS  (GOHL-jee)

The Golgi Apparatus is the processing, packaging and secreting organelle of the cell.

It is a system of membranes made of flattened sac like structures called CISTERNAE.

It works Closely with the ER, modifying proteins for export by the cell.  

LYSOSOMES (LIE-suh-sohmez)

Lysosomes are small spherical organelles that enclose hydrolytic enzymes within a single membrane.

Lysosomes are the site off food digestion in the cell. They are formed from pieces of the GOLGI APPARATUS that break off.

Lysosomes are common in animal, fungi, and protist cells, but rare in plant cells.

CYTOSKELETON

Just as your body depends on your skeleton to maintain its shape and size, so a cell needs structures to maintain its shape and size. In Animal Cells, an internal framework called CYTOSKELETON and it is used to maintain the shape of the cell.

The Cytoskeleton is a network of long protein strands located in the Cytosol, that are Not surrounded by a membrane.

The cytoskeleton consists of TWO Types of structures: MICROFILAMENTS AND MICROTUBULES.

MICROFILAMENTS

Microfilaments are not hollow and have a structure that resembles rope made of two twisted chains of protein called actin.

Microfilaments can contract, causing movement. As you would expect, muscle cells have many microfilaments.

MICROTUBULES

Microtubules are hollow, like plumbing pipes. They are thelargest strands of the cytoskeleton.

Microtubules are made of a protein called TUBULIN.

Microtubules have THREE FUNCTIONS:

    To maintain the shape of the cell.     To serve as tracks for organelles to move along within the cell.     When the cell is about to divide, bundles of microtubules known as SPINDLE

FIBERS come together and extend across the cell to assist in the movement of chromosomes during cell division.

CILIA AND FLAGELLA

Cilia and Flagella extend from the surface of the cell and assist in movement.

CILIA are short and hairlike and are usually numberous. FLAGELLA are long and whiplike and are often singular.

Unicellular organisms such as Paramecium and Euglena use cilia and flagella to move through water.

Sperm use flagella to swim to the egg.

In humans, beating Cilia line parts of the respiratory system, moving dust particles and bacteria away from the lungs.

THE NUCLEUS (plural, Nuclei)

1. The Nucleus is often the most prominent structure within a eukaryotic cell.

2. It maintains its shape with the help of a protein skeleton known as the nuclear matrix .

3. The Nucleus is the control center (BRAIN) of the cell.

4. Most cells have a single nucleus but some cells do have more than one (muscle cells, slime molds).

he nucleus is surrounded by a double layer membrane called the nuclear envelope . The nuclear envelope is covered with many small pores through which proteins and chemicals from the nucleus can pass.

The nucleus contains DNA, the hereditary information of the cell.

The DNA is in the form of a long strand called chromatin. During cell division, chromatin strands coil and condense into thick structures called chromosomes.

The chromosomes in the nucleus contain coded "blueprints" that control all cellular activity.

Most Nuclei contain at least ONE nucleolus (plural, Nucleoli)  (Figure 4.14). The nucleolus MAKES (syntheisizes) ribsomes (which in turn, build proteins).

When a cell prepares to reproduce, the nucleolus disappears..

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PLANT CELLS

Most of the organelles and other parts of the cell are common in ALL Eukaryotic Cells.  Cells from different organisms have even greater difference in structure.

Plant cells have three additional structures not found in animals cells - cell walls, vacuoles, and plastids.

CELL WALL

A Cell Wall DOES NOT REPLACE the cell membrane. Cells with walls also have a cell membrane.

The rigidity of cell walls helps support and protect the plant. .

VACUOLES

The vacuole is a large membrane-bound sac that takes up a large amount of space in most plant cells. It serves as a storage area, and may contain stored proteins, ions, wastes, or other cell products.

Vacuoles of some plants contain Poison that discourages animals from eating the plant's leaves.

PLASTIDS

Plastics are used in making or storing food. The most well-known is the chloroplast, (figure 4-17) an organelle that converts sunlight, carbon dioxide, and water into sugars.  This process is called photosynthesis.

Each chloroplast encloses a system of flattened, membranous sacs called tylakoids.  It is in the thylakoids that photosynthesis occurs.

Chloroplasts are green because they contain chlorophyss, a pigment that absorbs energy in sunlight.

Other plastids (chromoplasts) store reddish-orange pigments that color fruits, vegetables, flowers, and autumn leaves.

PATHOLOGY

As knowledge of human biochemistry and metabolism proliferated in the 20th century, many more laboratory tests were devised to distinguish normal states from disease states. Among the important tests are the measurement, by machine, of chemicals such as sodium, potassium, urea, and glucose in the blood; the similarly automated counting of various types of cells in the blood; and the determination of compounds in the urine, which can help diagnose kidney disease. Identification of the types of cells in the bone marrow and blood contributes to the diagnosis of some types of cancer.

IMMUNOLOGY

Using a human gene to make insulin would alleviate immunological problems associated with treating humans with insulin from other animals, and chemical synthesis of the gene would allow incorporation of methionine or some similar amino acid that would make it easier to separate the insulin produced from the carrier protein.

Basic Cell Types

Prokaryotic cells: no nucleus or cell parts - have cell walls and membranes

Eukaryotic cells: has a distinct nucleus - has membrane bound organelles

Cell Structure and Function

OrganellesThe parts of cells, each has its own characteristic structure and function

They perform jobs in the cell much like organs do in the body.

Organelles that occur in the cytoplasm are enclosed by membranes.

Membranes act as a barrier to make it possible for the chemical contents of the organelle to be different from the chemical environment of the cytoplasm.

Nucleus - large, centrally located - control center of the cell, has 3 parts

1. Nucleoplasm: thicker and less fluid than the cytoplasm. Houses the chromosomes (consisting of DNA). Transcription and translation occur here.

2. Nuclear membrane: Selectively permits passage of materials in and out of the nucleus.

3. Nucleolus: the factory where the RNA components of the ribosomes are assembled.

Cytoplasmconsists of mainly water containing amino acids, simple sugars and other substances needed to manufacture larger molecules.

Cell Membrane lining that surrounds the cell. Has 3 functions.

1. Encloses the cell, preventing inner materials from spilling out while maintaining cell shape

2. Regulates molecular traffic passing in and out of the cell.

3. Communicates with other cells and organs

Mitochondria - the cells power source- changes the chemical energy stored in food into compounds that are more convenient for the cell to use through a process called cellular respiration.

glucose + O2 → CO2 + H2O + ATP energy

There is a relationship between the #of mitochondria and the amount of work a cell does. Active areas of the body have a lot of mitochondria. Ex muscles

located in the cytoplasma double membraned structure where the inner membrane is highly infolded into cristae to increase inner surface area.mitochondria are able to reproduce themselves and have their own DNA.

Ribosome’sstructures responsible for protein synthesis they ensure correct amino acids and make peptide bondsfound on surface of E.R. (for producing proteins to be exported out of cell)also found free floating in cytoplasm in small groups called polysome’s – produce proteins that are to be used inside the cellAs with mitochondria the # is related to the amount of protein synthesis occurring in the cell.

Endoplasmic Reticulum (ER): transports material throughout the cell. 2 types of ER:

1.Smooth: responsible for fatty acid and phospholipids synthesis (main site of steroid synthesis). - NO ribosome’s on the surface

2. Rough: ribosome’s attached on the surface (looks rough)

involved in the manufacturing of proteins for use outside of the cellProtein move inside the ER to the Golgi Apparatus

Golgi apparatus

stacks of flattened membranes that function in the modification, packaging and distribution of proteins and other molecules

packaged into vesicles and distributed throughout the cell sent to the cell membrane for excretion

Vesicle

- a small vacuoleoften used to move certain compounds that need to be separated from the cytoplasm

often formed from the Golgi apparatus or from infoldings of the cell membrane

Vacuoles

membrane covered sacs that store material such as water, salts, proteins and carbohydratesnon living, and much larger in plant cells

Plant cells - larger in plants than animals - storage of waste products of metabolism.

Animal cells - digestion of food (eg: food vacuoles in Amoeba) - elimination of excess water.

Lysosomes

Membranous sacs that contain enzymes that breakdown ingested material. Formed by the Golgi bodies.

When a cell dies lysosomes release their contents into the cytoplasm, causing the cell to self-digest and in turn self destruct. “suicide cells”

Functions: a) attach to food vacuoles and digest contents b) enables a developing organism to destroy old or malfunctioning cell parts.

Plastids - accessory rings of DNA

- found only in plant cells.- have layers of membranes arranged in "coin-like" stacks called grana inside them.the individual sacks which make up a granum are called thylakoids.

- The inner portion of the chloroplast is called the stroma

3 types of plastids:Chloroplasts - most common - contain chlorophyl (in grana)

- site of photosynthesis

Chromoplasts - contain pigments other than chlorophyl - carotene, (orange and yellow carrots)

Leucoplast - starch storage plastid (eg. in potato)

Cell Wall

only in plant cellsmade of cellulose (sugars linked with a peptide bond)a 3 layered structure - surrounding the cell membranevery rigid (but porous) and difficult for animals to digest.

three layers; primary cell wall, middle lamella, and secondary cell wall

Cytoskeletoninternal framework of the cell that support the cells structure and causes the organelles to move.composed of 3 types of structures:

1. Microtubules - larger than microfilaments - cylinder shaped, (hollow), made of coiled protein called tubulin - found in cilia, flagella and centrioles

2. Microfilaments or Actin filaments

- long, thin, solid fibers of protein, 2 chains twisted - provide skeletal framework for the cell (cytoskeleton)

3. Intermediate filaments - support the nuclear envelope and the plasma membrane

Cillia and Flagella

- hair-like projections of the cell (cillia - short and many, flagella - long and few)- cell locomotion

- consist of a "9 + 2" arrangement of microtubules, 9 pairs along the outside and 1 pair in the middle, fig 3.12 pg 61

- both have a basal body at their base in the cytoplasm to act as an anchor. This has a "9 + 0" microtubule triplet pattern

Centrioles

- found in animal cells only- create spindle apparatus during cell division- also produce the basal bodies for flagella and cilia- usually 2 centrioles lie on either side of the nucleus at 90O angles (during times of nuclear division)- have a "9 + 0" microtubule triplets arrangement (looks like a star) Fig 3.11 pg 60

Differences Between Plant and Animal Cells:

plant cells have a cell wall , animal cells don'tplant cells have plastids , animal cells don'tplant cells usually have a large central vacuole , animal cells don'tanimal cells have centrioles , plant cells don't

BIOCHEMISTRY AND MOLECULAR BIOLOGY

In the 1960s the British biochemist John Kendrew determined the structure of myoglobin, a muscle protein, using purified protein and X-ray crystallography. His colleague Max Perutz subsequently determined the more complex structure of hemoglobin, which consists of four myoglobin-like units. However, in the same way that protein sequence analysis is now performed using DNA-based procedures, structural analysis is now normally carried out on protein that has been produced by artificially expressing the equivalent gene, for example, in bacteria. Using this method, the protein can be obtained in large amounts.

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MEDICINE

As one of the most dynamic areas of science, biochemistry has led to improved medicines and diagnostic agents, new ways of controlling disease, and greater understanding of the chemical factors that control our general health and well-being.

Biochemistry and Pharmacology

Certified by the American Board of Toxicology, Dr. Rao has over 20 years

of research experience in the fields of pharmacology and biochemistry with a

specialized focus on drugs and chemical-biological interactions, discovered

Cryptosin, a novel cardio-active glycoside, pharmacological hazard analysis,

vaccine and biologics product safety, and efficacy study design, analysis, and

review.

MOLECULAR BIOLOGY

Biochemistry and molecular biology are disciplines involved at the cutting edge of a revolution in biology. Molecular methods and the use of genetic engineering have given scientists unprecedented power to begin to understand the chemistry of life processes.

GENETICS

biochemical and genetic bases of common or representative diseases, including their symptoms and treatments. They will come to understand and be able to evaluate potential advances of diagnostic and treatment modalities.

Cancer.

Cancer continued to be a major concern of biochemists; as a cellular problem cancer is more amenable to biochemical study than diseases which involve an entire organ or system. Chemical carcinogenesis and chemotherapy (the cause and cure of cancer through chemicals) was generated. Chemotherapy is now effectively used to supplement surgical and radiation therapy of many different kinds of cancer. The proposal was made by oncologist Steven A. Rosenberg, who has developed an innovative technique for treating cancer. Rosenberg isolates white blood cells called tumor-infiltrating lymphocytes from the bodies of cancer patients. He treats the cells with a growth promoter called interleukin-2 and infuses them back into the patient, where they then attack the tumor.

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GENETICS

DNA carries the instructions for the production of proteins. A protein is composed of smaller molecules called amino acids, and the structure and function of the protein is determined by the sequence of its amino acids. The sequence of amino acids, in turn, is determined by the sequence of nucleotide bases in the DNA.

Biochemistry, study of the substances found in living organisms, and of the chemical reactions underlying life processes.