Model Answer Of Final Biomed Exam 2009

Cairo University Faculty of Science Department of

FINAL EXAM IN BIOLOGY

for the 1ST YEAR BIOMEDICAL

ENGINEERING STUDENTS Zoology

January 2009

Time allowed 2 hours

{1} The following sentences may be right or may be contain one wrong word. Put (√) in front the right one and a line under the incorrect word then write a correct word above it. {15 Marks (15X1)} ‫ لللللل للل للل للللل للللل لل للللل‬:‫)لللللل‬ (‫للللل‬ ‫ضع √ أو صحح‬ ‫ضع هنا خطا ً تحت الكلمة الخطأ‬ ‫الكلمة الخطأ‬ ‫هنا‬

√

1- Prokaryotes are the smallest, most primitive and most diverse group of organisms.

Plant

2- Animal cell has a large central vacuole, which is filled with cell sap.

hydrophobic or lipophilic

3- Steroid nuclei of cholesterol molecules in the cell membrane are hydrophilic i.e. fat soluble. 4- Passive transport does not require energy and

with

takes place against the concentration gradient. 5- Glucose is commonly transported into the cells

facilitated

by simple diffusion.

mature

6- The immature face of the cisternae of Golgi

or rER&nuc

apparatus is directed towards the cell membrane. 7- Lysosomes are sac-like membranous organelles

eukaryotic replication

present in all prokaryotic nucleated cells. 8- Transcription is the copying of DNA into DNA. 9- Meiosis occurs in the fertilized ovum and in

mitosis

different somatic cells of the body for growth. {1}

10- The 64-blastomere stage may be referred to a 32-

morula. 11- Sebaceous glands in the skin of mammals represent the branched tubular glands.

alveolar white

12- Elastic fibers of areolar connective tissue run in branched bundles. 13- Protein of the plasma membrane acts as

√

selective transport channels and carriers. 14- Both glycolipids and glycoproteins are called

√

the glycocalyx (cell coat). 15- Smooth endoplasmic reticulum is involved in

√

the synthesis of lipids and cholesterol.

{2} Mention ONE DIFFERENCE ONLY between the following scientific terms: {12 Marks (24X½)} (1) Ribosomes of prokaryotes Ribosomes of eukaryotes Small in size. Large in size. (2) Centrioles in plant cells Centrioles in animal cells Generally absent. Always present. (3) Cytolysis Plasmolysis When the cell is placed in a When the cell is placed in hypotonic solution, water diffuses a hypertonic solution, water into the cell causes it to swell and diffuses out of the cell causes often burst. it to shrink and die. 4) Exocytosis and cell membrane Endocytosis and cell membrane It adds membranes. It removes membranes. (5) Outer mitochondrial Inner mitochondrial membrane membrane It is smooth. It is folded (convoluted). (6) Rough endoplasmic reticulum Smooth endoplasmic reticulum It is covered by ribosomes. It lacks ribosomes. Or you can write opposite function. (7) Intracellular digestion Extracellular digestion It takes place inside the It takes place outside the cytoplasm. cell i.e. extracellular fluid. {2}

(8)

Central microtubules of the centrioles There are no central microtubules. (9) Paramecium (tool of movement) Cilia. (10) Alpha glycogen Appear as aggregations of rosette-shaped particles. (11) Exogenous pigments They come from outside to be accumulated in the cells. (12) Pyrimidine base of DNA Thymine. (13) 3ٓ end of DNA strand The end which has not a phosphate group or the end has a pentose sugar. (14) The binding between adenine (A) & thymine (T) Through two hydrogen bonds.

Central microtubules of the cilia There are 2 central microtubules. Euglena (tool of movement) Flagella. Beta glycogen Appear as single granules. Endogenous pigments They are synthesized by the cells. Pyrimidine base of RNA Uracil. 5ٓ end of DNA strand The end which has a phosphate group

The binding between guanine (G) & cytosine (C) Through three hydrogen bonds. (15) Messenger RNA Transfer RNA Carries the specific genetic codes Carries amino acids from DNA. (16) The number of the daughter The number of the daughter cells produced in each mitotic cells produced in each cell division meiotic cell division Two. Four. (17) G1 phase of the interphase G2 phase of the interphase Protein synthesis for the growth Duplication of centrioles. of the cell. (18) Mitosis Cytokinesis Nuclear division. Cytoplasmic division. (19) Spermatogonium Primary spermatocyte Small in size. Large in size. Or Produced at the end of Or Produced at the end of multiplication phase. growth phase. (20) Multiplication phase Maturation phase Takes place by mitosis. Takes place by meiosis. (21) Origin of nervous tissue Origin of muscular tissue Ectoderm. Mesoderm. {3}

(22) Cartilage Not penetrated by blood vessels.

Bone Penetrated by blood vessels. (23) Matrix of vascular connective Matrix of connective tissue tissue proper It is a fluid. It is a gelatinous. (24) Sensory neurons Motor neurons Carry nerve impulses (action Carry nerve impulses potentials) from the receptors to the (action potentials) from the central nervous system. central nervous system to the effector organs. {3} Write the SCIENTIFIC NAME of each of the following: {16 Marks (16X1)} 1- It is a branch of biology that deals with the study of the structures, functions, properties, formation and activities of cells. {Cell biology (cytology)} 2- It is a cell which may reach to more than 90 cm in large animals. {Nerve cell (neuron)} 3- It is very thin (about 80 – 100 Ǻ) in thickness, covering both the plant and animal cells. {Cell (plasma) membrane} 4- It is the diffusion of solvent (water) through the plasma membrane from an area of hypotonic solution to an area of hypertonic solution. {Osmosis} 5- It is formed from carrier proteis (α & β subunits), ATPase and ATP. {Sodium-potassium pump} 6- They are cell organoids which are bounded by a double membrane and are considered as the power house of the cell. {Mitochondria} 7- It is a process in which the cell is self-destructed. {4}

{Autolysis} 8- They have a role in metabolism of hydrogen peroxide (H2O2) and share in breakdown of purines and pyrimidines. {Peroxisomes (microbodies)} 9- They determine the shape of the cell. They also provide mechanical support of the cell. They are formed from microfilaments, intermediate filaments and microtubules. {Cytoskeleton} 10- It was used to protect DNA (genetic material) from cytoplasmic reactions that could damage it. {Nuclear membrane} 11- It is composed of a nitrogenous base, a pentose sugar and a phosphate group. {Nucleotide of nucleic acids} 12- A conical projection that produced by the egg surface at the point of contact between the sperms and the ovum. {Entrance} 13- It is the process by which female gametes are formed. {Oogenesis} 14- It is a classic example of the unicellular gland. {Goblet cell} 15- It is a covering epithelium that forms the epidermis of the skin. {Stratified squamous epithelium} 16- They are long cylindrical structures made of dimmers of alpha and beta tubulin (type of protein). {Microtubules} {4} Write on the following: {7 Marks} 1- Three functions only of rough endoplasmic reticulum. (1.5 Marks) 1- They are responsible for protein synthesis. {5}

2- They store the formed protein. 3- Packaging and segregation of the formed protein. 4- Delivery of the packaged protein to the Golgi apparatus. 2- Mention only one character of each of the following: (2 Marks) a) Metaphase: 1- The presence of metaphasal (equatorial)plate (plans). 2- The centromers of the chromosome pairs aligning along the microtubules at the center of the mitotic spindle. b) Anaphase: 1- It is characterized by movement. 2- The paired centromeres of each chromosome move apart. 3- Sister chromatids split apart into separate chromosomes and move towards opposite poles of the cell. 4- Because microtubules are attached to the centromeres, the chromosomes move centromere first in a V-shaped. 5- With continuous shortage of microtubules, chromosomes approach to the opposite poles of the cell. 6- The poles of the cell move farther apart, elongating the cell. 7- At the end of anaphase, the two poles have identical collections of chromosomes. 3- Mention only the stages of embryonic development. (1.5 Marks) 1- Cleavage. 2- Gastrulation. 3- Organ formation (organogenesis). 4- Blastula:

(2 Marks)

* It is a hollow spherical structure. * It′s wall is formed from one layer of cells; micromeres at the animal pole and macromeres at the vegetal pole. * It has a central cavity called blastocoel which is not connected to the exterior.

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