Zoology Chapter Two PDF

Zoology Dr: Gehan Safwat EL- Hussieny What does mean Zoology? Zoology is the branch of biology that studies the members of the animal kingdom and animal life in general. The field of zoology in the twentieth century mainly comprised these approaches: 1- Anatomy or Morphology 2- Taxonomy or Syst...

Zoology Dr: Gehan Safwat EL- Hussieny What does mean Zoology? Zoology is the branch of biology that studies the members of the animal kingdom and animal life in general. The field of zoology in the twentieth century mainly comprised these approaches: 1- Anatomy or Morphology 2- Taxonomy or Systematics 3- Physiology 4- Embryology 5- Evolutionism 6- Genetics 7- Cellular and Molecular Biology 8- Ecology 9- Ethology  What does the cell mean? Simple Prokaryote bacteria Cells Complex Eukaryote animal plant fungi *** Cell is the smallest metabolically functional unit of life and holds all structures and molecules that can support life. The Prokaryote and the Eukaryote Characteristic Prokaryotes Eukaryotes Size 0.2- 2.0 m in diameter 10-1000 m in diameter Nucleus No nuclear membrane True nuclear membrane or nucleoli Present or nucleoli Cell wall Chemically Complex as present in a simple chemical bacterial cell to prevent part form i.e. Cellulose and of the abiotic stresses lignin Plasma No Carbohydrates Carbohydrates and sterols membrane and lacks of sterols both function as receptors Cytoplasm No cytosketeton and Cytosketeton and cytoplasmic streaming cytoplasmic streaming Chromosome Single circular chromosome Multiple linear chromosomes lacks of histones lacks of histones Cell division Binary fission Mitosis Sexual No meiosis involves meiosis Animal Cell 1-Plasma Membrane The plasma membrane, which serves as a diffusion barrier between the cell and its environment. All living cells have plasma membranes. A "diffusion barrier" prevents the loss of cellular materials by interfering with the physical tendency of molecules to spread out. It also prevents many substances from diffusing into the cell. And it also controls the movements of various substances and objects into and out of the cell.  Lecture two Dr: Gehan Safwat EL- Hussieny Plasma Membrane 1-Selectively permeable membrane (selective transport) (Allow nutrient either organic or inorganic to enter the cell and the waste materials to leave the cell) 2- holding the cell constituents together 3- Keeping substances from entering  Animal Cell Plasma membrane Cytoplasmic matrix Cytosol Cell Organelles 1-Endoplasmic Reticulum Cytoskeleton 2- Ribosomes 3- Golgi Apparatus Cytoplasmic filaments 4- Lysosomes Microtubules -Microfilaments 5- Mitochondria -Intermediate filaments -Thick filaments 6- Centrioles 7- Cell Nucleus  CYTOSOL 1-It is capable of behaving like a fluid or a solid Near the plasma membrane more like a solid ECTOPLASM In the interior of the cell is generally in a more fluid state ENDOPLASM 2- It is the “SOUP” within which all the other cells organelles reside and where most of the cellular metabolism occurs. 3- It is full of proteins that control cell metabolism including: -signal transduction pathways -Glycolysis -intracellular receptors -transcription factors  1- Cytoplasmic filaments -Microfilaments -Intermediate filament -Thick filaments 5-9 nm diameter 8-12 nm Up to 22 nm Microfilaments Specification -They are solid rods made of a protein known as actin - Mostly located at the edges of the cell Microfilament Function 1- They are designed to bear large amounts of tension. 2- Generate the forces used in cellular contraction and basic cell movements. 3- Enable a dividing cell to pinch off into two cells. 4- Key role in development of various cell surface projections.  Intermediate filament Specification -They are very broad class of fibrous proteins. -They are very abundant in cells that are often subjected to high mechanical stress in vivo. -Found in neurons and glial cells. Function 1-Tension- bearing elements to maintain cell shape and rigidity. 2-Serve to anchor in place several organelles such as nucleus. 3-Bind to variety of associated proteins to improve stability or provide attachment sites for other protein assemblies such as Actin (microfilaments) and microtubules 4-Most animal epithelial cells contain Keratins which is diverse family of intermediate filaments.  Mutation in intermediate filament gene Epidermolysis bullosa simplex Amyotrophic lateral sclerosis (Lou Gehrig’s Disease) Defective in keratins (Fibrous Defects in desmin (A protein protein, the main component of the found in muscle cells that skin, hair and nails contributes to forms intermediate filaments). the water proofing of skin).  Thick filaments Specification -Rich in fibrous protein called ( myosin). -Found mainly in cell muscles Function 1-They are involved in their contractile activity  2- Microtubules Specification -They are straight, hollow cylinders -25 nm in diameter -They are biopolymers that are composed of subunits made from two Proteins, alpha-tubulin and beta-tubulin Function -Serve as conveyor belts moving other through the Cytoplasm. -Structural support. -Gives shape to cells. -Play an important role during cell division (mitosis) by participate in the formation of spindle fibres. -Serve as a highway system along which organelles can be transported Cell Organelles  Animal Cell Plasma membrane Cytoplasmic matrix Cytosol Cell Organelles 1-Endoplasmic Reticulum Cytoskeleton 2- Ribosomes 3- Golgi Apparatus Cytoplasmic filaments 4- Lysosomes Microtubules -Microfilaments 5- Mitochondria -Intermediate filaments -Thick filaments 6- Centrioles 7- Cell Nucleus  Ribosomes Structure -All living cells contain ribosomes. -They are tiny organelles composed of approximately 60% (rRNA) and 40% (protein). -The ribosomes are not bound by a membrane and they are much smaller than other organelles. -They are mainly bound to ER and the nuclear envelope. -If they attached to mRNA called polysomes.  Ribosomes Construction -Ribosomes are produced and assembled in the nucleolus, ribosomal proteins(40%) -Combine with the four rRNA strands (60%) to create the two ribosomal subunits (one small and one large). -The ribosome units leave the nucleus for the purpose of protein synthesis. However, if the protein is not carried out, then the two subunits of the ribosome are separated.  Ribosomes Function [Protein production machinery for the cell ] -Most abundant in cells that are active in protein synthesis i.e. (Pancreas and brain cells) {Protein synthesis} It requires the assistance of two other kinds of RNA i.e. Messenger RNA (mRNA) and Transfer RNA (tRNA). -mRNA provides the copy sequencing for specific gene -tRNA is to brings the protein building blocks (amino acid) to the ribosome. Once the liner protein polymerized, it is released from the ribosome to the ER or to Golgi apparatus  3- Golgi Apparatus (GA) -The GA also called Golgi body or Golgi complex. -They are universal in both plant and animal cells. Structure -the unit of Golgi Apparatus called cisternae, it looks like a cup-shaped -5 to 8 cisternea linked by tubular connections into a single complex called a stack -Each animal cell generally has 10 to 20 One Golgi Stack stacks  Golgi Apparatus (GA) Function 1- [ Modifies proteins, lipids and carbohydrates ] 2- [ Distribution and shipping department for the cell chemical products ] For example:- Proteins and lipids have been built in the ER bud off in tiny bubble called vesicles and move to reach the Golgi apparatus The vesicles fuse with Golgi membranes and release stored molecules internally Enzymes present in the Golgi internal space (lumen) modify those by add small molecules or chops tiny pieces off the ends. These modified product is exported from the GA in a vesicle directed to its final destination inside or outside the cell to be function in the organism. Some of these are returned to the ER or may become lysosomes.  Golgi Apparatus (GA) Function Continue…. The mechanism of incoming transport vesicle and outgoing transport vesicles is happened in orders through the two faces of each Golgi stack. First, the cis face is one end of the Golgi stack where molecules enter to be modified. This end always near the ER as most of the material it receives comes. The second end of the Golgi stack called trans face where the modified molecules shipped in One Golgi Stack the form of smaller vesicles. This end is positioned near the plasma membrane of the cell. The enzymes contained in the lumens of the cisternae between the faces are distinctive and help to modify the molecules during their transition from the cis to the trans poles of the Golgi complex.  Golgi Apparatus (GA) Function Continue…. 3- [ Generate a variety of macromolecules on its own i.e. (polysaccharides) ]  Centrioles (Centrosome) **Found ONLY in animal cells located together near the nucleus. **Each one made of nine bundles of microtubules (three/ bundle). Function The centrioles are play a notable role in cell division. Cell Organelles Endoplasmic Reticulum  Endoplasmic reticulum (ER) Structure and Specification - ER is a network of flattened single continuous membrane (sacs and tubules), which fill more than 10 % from the total volume of the cell -The large continuous complexly arranged internal space, usually called cisternal space Function - The ER, has been known as the main Transportation system to a wide range of biochemical compounds (mainly Proteins) for use inside and outside of the cell. - Also involve in manufactures and processes these biochemical compounds - ER resident proteins e.g. Chaperon protein (Chaperone immunoglobulin- binding protein, BiP), help to identify any transiently proteins that have been improperly built or processed and keeps them from being sent to their final destinations.  There are two different parts in the ER, they are functionally different: (Rough and Smooth) Rough ER Smooth ER under the It looks bumpy, as the outer It looks Smooth, because it microscope surface of that part of ER is has no ribosomes are lined (morphologies) covered with ribosomes. on their outer surfaces -Mainly production and -Production of lipids (fats) processing of proteins that will Mainly involved in proteins be exported. export by the transport vesicles system. Function -In most instances, the linear- proteins (long chain of amino acid) synthesized by the - help in the Carbohydrate ribosomes enters the metabolism cisternae to be folded into the 3D configuration and add other substances such as carbohydrates  Rough ER Smooth ER Due to their physical membranous -Building specific connection with the nuclear envelope substances (blocks) to as a single compartment. help detoxification of *So the transport vesicles system are drugs and poisons. not needed, and the two organelles -Plays a role in storage *enables to share information in a calcium and calcium Function very efficient manner, metabolism, with help in e.g. various cellular activities, if the ER starts to has functional e.g. problems, and unfolded proteins In muscle cells the accumulate, which can be extremely smooth ER releases hazardous to the cell, the ER sends calcium as signal to a signal to the nucleus to slow down trigger muscle the ribosomal translation proteins to contractions gain more time to catch up on its protein folding, thus maintaining cellular health. Extensive In most cell much more extensive In brain and muscle or appearance than the smooth ER Liver (detoxification tissues) Structure:- Lysosomes -Lysosomes are spherical organelles contained by a single layer membrane, this membrane protects the rest of the cell from the digestive enzymes contained in the lysosomes. -Lysosome matrix is favorable for enzymatic activity with a pH about 4.8 Function:- 1- To digest macromolecules which enter the cell primary lysosome infuse Digestion Macromolecules Secondary lysosome primary Simple (Heterophagosome) lysosome molecules (e.g. Food) 2- To breakdown nonfunctioning organelle, given more space in the cell and the products are recycled and reused to compose a new parts of cells primary lysosome infuse Digestion Secondary lysosome primary Simple Old organelle (Autophagosome) lysosome molecules 3- To help in the white blood cells battle and digest bacteria, viruses, and other foreign intruders Where could you find the Lysosomes: Most numerous in disease fighting cells (white blood cell) There are many diseases related to the malfunctioning of lysosomes. (Discus and list some of them) -There are fifty overall.. these diseases show characterizes by specific enzyme deficiencies. -These disease show characteristic Patterns of the accumulation of polysaccharides or lipids in: -Tissue of nerve cells -Muscle -Liver **Some of these diseases: Cystic fibroses, lysosomal storage disease. Pompe’s disease or Tay- Sachs disease. Tay-Sachs disease:- It’s a genetic disease Cause an absent of essential enzyme that breakdown complex lipids called gangliosides. The accumulation of the gangliosides can damages the nervous system and death in early childhood.  Mitochondria Structure:- They are rod-shaped. From 1-10 micrometers in length. The cell could have one single large mitochondria to thousands Mitochondria are found in nearly all eukaryotes. Each one has two membranes, inner and outer. The inner one is highly convoluted so that a large number of infolding called cristae to increase the surface area for cellular respiration. Continuous the Structure:- It is different from the most other organelles because it has its own circular DNA and reproduces independently of the cell. Mitochondrial DNA is localized to matrix, which also contains oxidative (respiratory) enzymes, ribosomes.  Continue; Mitochondria Function:- organelles that can be considered the power generators of the cell, converting the oxygen and nutrients into adenosine triphosphate (ATP). mitochondrial DNA doesn't get shuffled every generation, so it is presumed to change at a slower rate which is useful for the study of human evolution. It could be used as a tool for identifying corpses or body parts.  Cell Nucleus Structure: Generally there is only one nucleus per cell but there are exceptions, such as Siphonales group of algae. It is about 10% of the eukaryotic cell’s volume. It has: the nuclear envelope (double-layered membran) separates the contents of the nucleus from the cytoplasm. the envelope is riddled with holes called nuclear pores that allow specific types and sizes of molecules to pass back and forth between the nucleus and cytoplasm.  Continue; Cell Nucleus It is attached to the endoplasmic reticulum and is usually studded with ribosomes. The semifluid matrix found inside the nucleus is called Nucleoplasm. Within the nucleoplasm, most of the nuclear material consists of chromatin. And there are two basic types of chromatin (Euchromatin &Heterochromatin) What is the different between the two types? (Home work) The nucleus has nucleolus is prominent sub-nuclear Structure that is not bounded by membrane. it is 25% of the total volume of the nucleus. it appears like a large spot and eukaryotic cells often contain a single one but several are also possible.  Continue; Cell Nucleus Function:- There are two major functions: 1- It stores the DNA. 2- It coordinates the cell’s activities which include growth, metabolism, protein synthesis and cell division  Cell division There are three types of cell division: Meiosis: when the number of chromosomes is halved. it usually occurs during the formation of the gametes. During the meiosis, the normal diploid (2n) chromosome number of the somatic (body) cells is reduced by half to the typical (n) chromosome number of the gametes. (oocytes). Amitosis: it is often referred to as direct cell division. it is a type of cell division where the cell breaks into two parts by constriction of the nucleus and cytoplasm. There may be unequal distribution of the chromosomes (Placenta) Mitosis: it is indirect cell division, include an exact division of the cytoplasm (cytokinesis) and division of nucleus materials (karyokinesis) between the two young cells. (the most common type of cell division in animals and plants) Explain the basic differences between mitosis and meiosis.. (home work) Stages of mitosis: 1-PROPHASE 2-METAPHASE 3-ANAPHASE 4-TELOPHASE -Chromosomes become visible. -Chromosomes become -Centromeres split -Chromosomes fully condensed fainted and become -Each divided into two (each chromatid now not visible. chromatides. -Centromeres aligned called chromosome) midway in the mitotic -Nucleolus appears -Centrioles duplicate - The two spindle, referred to as and migrate to opposite the metaphase plate of Chromosome sets -Nuclear membrane sites. move to opposite appears the cell. poles of the cell. -Organelles -Nucleolus disappears distributed equally -Nuclear membrane between the two disappears new young cells -Mitotic spindle appears between the two centrioles  Cell Death There are two ways in which cells die: Necrosis Apoptosis Death by injury Death by suicide  Necrosis Cells are damaged by injury, such as: -Mechanical damage -Exposure to toxic chemical Which kind of changes could happen? 1-The cells and the organelles swell 2-The cells contents leak out 3-Removal of dead cell combined with inflammatory reactions. Example: Necrosis of toes Tissue death occurs when there isn’t enough blood supplied to the toes, whether from radiation or chemicals  Apoptosis Cells are death by suicide: Helps eliminate unwanted cells Which kind of changes could happen? 1- Shrink 2- develop bubble on their surface 3- have the chromatin (DNA) in their nucleus degraded. 4- have their mitochondria break down 5- break into small fragments 6- the phospholipid, which is normally hidden within the plasma membrane, is exposed on the surface 7- remove the dead cell fragments without inflammatory reactions Why should a cell commit suicide? There are two different reasons. 1-Programmed cell death is needed for proper development as mitosis. Example: The formation of the fingers and toes of the fetus requires the removal by apoptosis of the tissue between them. 2- Programmed cell death is needed to destroy cells that represent a threat to the integrity of the organism Occur when cell is damaged beyond repair, or infected with a virus. To prevent it from sapping further nutrients from organism, or the spread of viral infection.  Cell Cycle Stage of cell cycle Major Events During That Stage First gap (G1 phase) It is a period between the birth of the cell and the beginning of its division. (cell growth) DNA synthesis (S phase) The cell prepare itself for division by DNA duplicated (each chromosome is composed of two identical chromatid) Second gap (G2 phase) Tubulin (microtubules fibrous protein) synthesis for the formation of spindles Mitosis (M Phase) It is a period of cell division physically. Go phase :- Some types of cells enter to this phase by leave the cell cycle (cell division) i.e.:- A- Cells that permanently stopped dividing (as nerve cells) B- Semi-permanently (as liver and kidney cells) which can only be induced to begin enter the cell cycle under stimulation effect called facultative dividers  Evolution What does the EVOLUTION mean? Process of change that produces new species from pre-existing species. What are the causes of EVOLUTION? 1-Adaptive Radiation: When the species enters a new environment and face different circumstances. 2-Convergent evolution: When the environment selects similar adaptation. 3-Stabilizing selection: When the organism will be Successful in its environment if any change occurs. (Mutations) What are the theories of EVOLUTION? Lamarck: Environment and its changes produced needs which resulted in the organism directing into own adaptation. Darwin: The random variation was already present And the activity of environment produced adaptation.  Echinodermata Means animal with spiny skin. e.g. Starfish Sea cucumbers. What are the characters of echinodermata?(HW) 1- Most are pentamerous radical symmetry. 2-They go through a bipinnaria larva stage during the Development. 3-they have tube feet. 4- they have an endoskeleton.  Behaviour Innate behaviour: The organism is born knowing how to do it. Instinctive behaviour: patterns are often repeated in response to changes in the environment. As some animals are active in the day and others during night  Nutrition The active site of an enzyme is the part of the enzyme that binds to the substrate to catalyze it into end product. Types of nutritive substances: 1-Orginic:Fats,proteins and vitamins 2-Inorganic: minerals 3-Iodine 4-phosphate. Types of nutrition: Herbivores: feed on plant Carnivores: feed on flesh Omnivores: feed both animal and plant