Exam 1 Flashcards

Question

Prone

Answer 1

vertical plane that divides the body or organ into a right and a left side.

Answer 2

It’s Sagittal plane running through the nose & giving equal right & left halves

Answer 3

PLANE:Its Sagittal plane that does not run in the middle and therefore does not gives equal right and left halves.

Answer 4

divides specimen into an anterior and a posterior section.

Answer 5

divides specimen into a superior and an inferior part.

Answer 6

divides specimen into a diagonal section

Answer 7

A body cavity is a space within the body that contains internal organs.Cavities help to protect, separate and support organs.

Answer 8

It consists of a) Cranial Cavity and b) Vertebral Cavity a) Cranial Cavity – it contains the brain b) Vertebral Cavity – contains the Vertebral column and spine

Answer 9

It consists of a) Thoracic cavity b) Abdominopelvic cavity

Answer 10

Abdominopelvic cavity is further divided into abdominal cavity and pelvic cavity by the Pelvic Diaphragm

Answer 11

located superior to the DIAPHRAGM and contains areas that house the LUNGS which are separated by an area called the MEDIASTINUM which houses the heart.

Answer 12

The mediastinum is a region between the lungs, from the sternum to the vertebral column. The heart is located within the mediastinum (in

Answer 13

Exists right below the diaphragm and contains many of the digestive organs.

Answer 14

Exists inferior to the abdominal cavity and contains the lower digestive organs, some of the organs of the urinary system as well as the reproductive organs.

Answer 15

It is a thin membrane that lines the cavities that open to the outside of the body. Examples are nose, mouth, Anus. This membrane produces a fluid called Mucus (pay attention to the spelling), that protects the surface of these cavities.

Answer 16

A serous membrane is a thin sheet of cells that line cavities that do not open to the outside of the body. They produce a small amount of fluid called SEROUS FLUID

Answer 17

Types of Serous Membrane: i) Pleura-(lung) ii) Pericardium- (heart) iii) Peritoneum- (abdomen)

Answer 18

proton: subunits that are positively charged found within the NUCLEUS of the atom neutron: " " " neutral that are also " " " " " " " electrons: " " " negatively charged found moving in ENERGY SHELLS around the nucleus

Answer 19

of protons # of protons + # of neutrons

Answer 20

same # of protons but diff. # of neutrons

Answer 21

the amount of time required by the element to reduce its strength of radioactivity to half

Answer 22

is the outside shell of the atom. When a chemical reaction occurs, the electrons in the outside orbital will be the only part of the atom that will participate.

Answer 23

is an element whose valence electron shell is full. EX. Noble gases in the periodic

Answer 24

is an element whose valence shell is empty.

Answer 25

Atoms do not normally exist in nature, but join or BOND together in different ways to make a MOLECULE, a structure formed by atoms bound together by chemical bonds. Thus a molecule is formed when two or more atoms of the same kind or of different kind combine they form a molecule. When two or more different types of atoms chemically combine they form a compound.

Answer 26

1. IONIC BOND: bond formed by 1 atom losing an outside electron(s) to another, which gains the e-. These bonds are fairly strong. If you dissociate a molecule that has been held together by ionic bonds, ions results,

Answer 27

A charged atom. Ions are also referred to as electrolytes. The human body is full of ions, resulting from chemical reactions. The charges on these ions are extremely important in the workings of the body. Some common ions include: Na+, K+, Cl+, etc

Answer 28

They dissociate in water and consist of cations (+) and anions (-). They conduct electric current and the currents is detected by the electrodes.

Answer 29

They do not dissociate in water and do not conduct electricity.

Answer 30

This type of bond is extremely important in life. Covalent bonds result when 2 or more atoms form a molecule by sharing of electrons ( these electrons will be found in the outer orbit). The bond that is formed is very STABLE and Strong and allows for DIVERSITY of molecules that can be formed. This is the way CARBON binds together.

Answer 31

bonds in a molecule so that the molecule is polarized in portions but neutral as a hole. molecule is not polarized Polar : unequal sharing of electrons between 2 different atoms held together by covalent Non-polar: equal sharing of electrons between 2 different atoms in a molecule so that the

Answer 32

Think of these more as an attraction than actual bonding between molecules, especially important in DNA structure (genetic material). It is important in maintaining molecule’s 3

Answer 33

When there is formation or breaking of bonds, chemical reactions are occurring. Thousands of reactions occur within the body per minute, rearranging atoms and leading to new molecules that have new chemical properties and new functions. Life is dependant upon these chemical reactions.

Answer 34

These are substances that enter into a chemical reaction.

Answer 35

These are substances that result from the reaction.

Answer 36

In these reactions the forward reaction equals the backward reaction

Answer 37

is the sum of all chemical reactions occurring in the organism. This process can be divided into 2 subtypes: CATABOLISM and ANABOLISM.

Answer 38

1. CATABOLISM: reactions in which the chemical structures are broken down into smaller structures. ex. NaCl à Na+ + Cl-

Answer 39

2. ANABOLISM: reactions in which there is a combination of 2 or more chemical structures, resulting in a larger structure. ( protein synthesis)

Answer 40

Hydrolysis-add H2O and break (catabolism)

Answer 41

Hydrolysis-add H2O and break (catabolism)

Answer 42

Most organic molecules are large, contain carbon, and have covalent bonds. Organic chemicals that are biologically active are called biochemicals. There are 5 major organic molecules, all of them containing CARBON and HYDROGEN, as well as other elements. These 5 are CARBOHYDRATES (ex Glucose), LIPIDS (ex Fatty Acid), PROTEINS (ex Amino Acid), NUCLEIC ACIDS (ex Nucleotides)and ATP.

Answer 43

molecules that do not contain CARBON. These inorganic molecules include water, acids, bases and salts. Exceptions are CO2, CO, and HCO3

Answer 44

is a vital inorganic molecule. ( H2O) It makes up 50-60% of body weight and 70-95% of the cell a. It is an excellent solvent, dissolving many molecules (solutes) why? Because it is a polar, covalent molecule with hydrogen bonds and it can make hydration shell around each ion of the solute. b. It participates in many chemical reactions c. lubricant/protection d. temp regulation (high specific heat) e.adhesion attraction between water molecules and the container walls f. cohesion (capillary action) g. water can exist in all 3 states ie solid, liquid, gas

Answer 45

Molecule that when dissociates (ionizes) will not yield H or OH. The most plentiful salts in the human body are the calcium phosphates that are found in teeth and bones. When they become ions, they are important in nervous system and muscle contraction

Answer 46

Molecule that when ionizes (comes apart) in water, will yield H+ ion. It is a proton donor. ION = charged atom. HCL gives H+ and CL-

Answer 47

Molecules that when dissociates in water will yield OH ions (OH)- or is a proton acceptor. NaOH gives Na+ and OH-

Answer 48

A substance that has the capacity to maintain pH at a specific level (in other words, resists changes in pH). It is a combination of weak acid-base pair.

Answer 49

folds in multiples of 10.

Answer 50

Acidosis is an increased acidity in the blood and other body tissue (i.e. an increased hydrogen ion concentration). If not further qualified, it usually refers to acidity of the blood plasma. Occurs below pH of about 7.35?

Answer 51

Alkalosis refers to a condition reducing hydrogen ion concentration of arterial blood plasma (alkalemia). Generally, alkalosis is said to occur when pH of the blood exceeds 7.45. The opposite condition is acidosis (when pH falls below 7.35).

Answer 52

Organic chemicals that are biologically active are called biochemicals.

Answer 53

Compounds that are made out of C, H and Oxygen. Formula is CH2O. They are of 3 types Monosaccharides, Disaccharides and Polysaccharides. FUNCTIONS: supply energy and structure

Answer 54

a monosaccharide

Answer 55

a disaccharide

Answer 56

Long chains of many monosaccharides bonded together. These are also too large to get through a cell membrane and are usually used as a storage molecule. ex. GLYCOGEN = a polysaccharide that is made up of bonded glucoses. This large structure serves to store glucose in the liver and muscles of animals. When needed the bonds are broken and free glucose is transported into the cells. Polysaccharides form part of cell surface markers.

Answer 57

Simple sugars that are composed of 1 molecule. ex. glucose and fructose

Answer 58

double sugars that are composed of 2 monosaccharides, covalently bonded Examples of these would be SUCROSE (table sugar) and MALTOSE.

Answer 59

polysaccharide in animals (starch and cellulose in plants).

Answer 60

These have same chemical composition but different arrangements ex is Glucose and Galactose

Answer 61

Structural Isomers- switching of attached groups at the specificcarbon positions Stereoismers- switching of atoms at the same carbon position Enantiomers- mirror image

Answer 62

Lipids are substances that will not dissolve in water; made also from C, H, and O. FUNCTIONS: Energy source, food storage, structure (cell membrane), steroid formation, insulation and protection.

Answer 63

Examples of lipids found in the body are: triglycerides (Fat), the most abundant form of fat in the human body, composed of 1 glycerol plus 3 fatty acid chains.

Answer 64

Phospholipids, an important part of the cell membranes and steroids (include sex hormones and cholesterol).

Answer 65

Steroids are 4 ring C compounds and they give fluidity to the cell membrane EX of Steroids are: – Cholesterol – bile salts – Estrogen – testosterone. Functions of Steroids: – They are physiological REGULATORS – They give fluid mozaic model to cell membranes.

Answer 66

molecules made from C, H, O and N and sometimes I. Ex is insulin. FUNCTIONS: Energy (last resort), structure (cell membrane), hair and nail (Keratin), protection (antibody immunoglobulins), membrane transport (carrier proteins), regulate processes (enzymes), muscle contraction

Answer 67

(not synthesized by the organism therefore essential in the diet)

Answer 68

(synthesized by the organism).

Answer 69

Dipeptide ….2 Amino Acid joined by a peptide bond Tripeptide …..3 Amino Acid joined by peptide bonds Polypeptide …4 or more Amino Acids joined by peptide bonds

Answer 70

Dipeptide ….2 Amino Acid joined by a peptide bond Tripeptide …..3 Amino Acid joined by peptide bonds Polypeptide …4 or more Amino Acids joined by peptide bonds

Answer 71

PROTEIN THAT INCREASES THE RATE OF CHEMICAL REACTIONS (ie:CATALYST). Enzymes are found inside of cells and in fluids outside of cells and are responsible for the thousands of chemical reactions that occur within the body. Their 3-D shape contains active site where reactants attach. This leads to Induced Fit Hypothesis meaning the enzyme changes it’s shape to accommodate the shape of the specific reactants. This is called the tight fit. – Enzymes are proteins that function as catalyst – catalyze reactions at the plasma membrane. – small intestine produces enzymes that break dipeptides to amino acids

Answer 72

These are inorganic substances that can combine with active site on an enzyme and thus make nonfunctional enzymes functional

Answer 73

are the Organic cofactors.

Answer 74

serious genetically transmitted disease in which the protein that carries oxygen in red blood cells, HEMOGLOBIN, is abnormal. Just 1 of the amino acids that form hemoglobin ( a protein) are not correct in a sequence of 574 amino acids(Glutamic acid is replaced by Valine at Carbon # 6). This leads to malformed hemoglobin and malformed red blood cells. Some of these RBCs will become sickle shaped and cause the painful symptoms. This disease provides protection against malaria in African race. There is no cure for this disease.

Answer 75

These are huge molecules that are important in inheritance. Main types of nucleic acids are DNA, RNA and ATP. Nucleic Acids are composed of C, H, O, N and P

Answer 76

double strand helix has genes structure: deoxyribose (5 C sugar) Nitrogen base combinations: adenine + Thymine guanine + cytosine

Answer 77

single strand makes protein structure: ribose (5 C sugar) Nitrogen base combinations: \*uracil\* + thymine guanine + cytosine

Answer 78

ATP is an important organic molecule found in all living organisms. It is made up of 1 adenosine molecule and 3 phosphate groups. There is energy stored in the bonds of this molecule and it is this energy that is used in the chemical reactions, muscle contraction and anabolism in the cells.

Answer 79

MONOMERS OR COMPONENTS: monosaccharides POLYMER OR LARGER MOLECULE: polysaccharides TYPE OF LINNKAGE: glycosidic linkages

Answer 80

MONOMERS: fatty acids POLYMERS: triacylglycerols LINKAGE: ester linkages

Answer 81

MONOMERS: amino acids POLYMERS: polypeptides LINKAGES: peptide bonds

Answer 82

MONOMERS: nucleotides POLYMERS: polynucleotides LINKAGES: phosphodiester linkages

Answer 83

Basic unit of life – Protection and support through production and secretion of various kinds of molecules (HCl) – Movement (microtubules - pseudopods). – Different kinds of cells occur because of specialized proteins produced in these cell (muscle, nerve cells) – Communication. Cells produce and receive electrical and chemical signals(nerve) – Cell metabolism and energy release (mitochondria) – Inheritance. Each cell contains DNA. Some cells are specialized to gametes for exchanging DNA during sexual intercourse

Answer 84

Earliest type of cell, although still present on earth today. Lacks an organelle called the Nucleus. Examples are bacteria. Study these in microbiology.

Answer 85

Cells that have at least 1 nucleus at 1 part of their life (ex RBC). Plants and animal cells are examples. We will be concerned about eukaryotic cells in this class. Humans have 50 - 60 trillion eukaryotic cells, and there are 200 different types of cells.

Answer 86

This is the outside layer of the cell as well as the boundaries around most organelles. Also referred to as cell membrane. According to the FLUID MOSAIC MODEL, the membrane is actually a PHOSPHOLIPID BILAYER. According to this model, the plasma membrane is not rigid or static, but is flexible and moving. \*On the outside of the Cell, the Plasma membrane is positively charged compared to the inside which is negative due to the gathering of specific ions along the outside and the inside of the membrane

Answer 87

Present on outer surface. It is a combination of : • carbohydrates and lipids (glycolipids) • Carbohydrates and proteins (glycoproteins)

Answer 88

These molecules allow cells to identify one another or other molecules. They help with the following processes. – Immunity – Recognition of oocyte by sperm cell – Intercellular communication Plasma Membrane has a HYDROPHILIC side and a HYDROPHOBIC portion.

Answer 89

\*Extends from one surface of the plasma membrane to the other \* make channels

Answer 90

• present on the inside or outside of the memb. ## Footnote * These proteins provide markers with an attachment site * May make channels * May make receptors * May make enzymes * May make carriers

Answer 91

Here the hydrophilic region faces inward; the charge will determine which molecule can pass through. ## Footnote The type of channels are as follows. * A) Nongated ion channels: always open * B) Gated ion channels can be open or closed. Types of gated channels: – Ligand gated ion channel: Opening of the channels depend on small molecules (ligands). These mol. bind to proteins or glycoproteins and open the gates – Voltage-gated ion channel: Opening of the channels depends on membrane charge

Answer 92

These are proteins present in the membrane. They have receptor sites that ## Footnote allow molecules to attach. These receptor molecules may help with intercellular communication

Answer 93

* Tight Junctions – (staples) * Desmosomes and Hemidesmosomes (thumb tacs) * Gap Junctions – (gaps act as passages)

Answer 94

Movement of a substance from an area of higher concentration to lower ## Footnote concentration, ie down the concentration gradient. Example: Oxygen and CO2(lungs)

Answer 95

\* Simple diffusion \* Faciliated diffusion \* Osmosis \* Filtration

Answer 96

Movement of a substance from area of higher to lower concentration with the ## Footnote help of carrier proteins (ie membrane transport integral proteins). Substances are often large and lipid insoluble. Example: glucose, Na+

Answer 97

Movement of WATER molecules through a semi-permeable membrane along the ## Footnote concentration gradient of the water. This concentration of solutes inside the cell compared to outside the cell will have an effect on the concentration of water molecules, and therefore on the movement of the water. Types of osmosis: ISOTONIC, HYPOTONIC, HYPERTONIC

Answer 98

It works like a sieve. Here there is movement of a substance through the membrane from ## Footnote an area of higher PRESSURE to an area of lower PRESSURE. Example: used by kidneys in the formation of urine.

Answer 99

– force required to prevent osmosis ie (stop water from moving out of the solution or the ## Footnote environment over which the osmotic pressure is acting) – Greater the solute concentration greater is the osmotic pressure of the solution – Greater the osmotic pressure of a solution greater will be the movement of water into this solution from outside

Answer 100

1. When the concentration of x molecules outside the cell is low, the transport rate is low because it ## Footnote is limited by the number of molecules available to be transported. 2. When more molecules are present outside the cell, as long as enough carrier proteins are available, more molecules can be transported; thus, the transport rate increases. 3. The transport rate is limited by the number of carrier proteins and the rate at which each carrier protein can transport solutes. When the number of molecules outside the cell is so large that the carrier proteins are all occupied, the system is saturated and the transport rate cannot increase

Answer 101

Are of two types ## Footnote i) Chemical - compounds ii) Physical – solutions

Answer 102

Have two components: ## Footnote i) Solvent ii) Solute

Answer 103

i) Hypo ## Footnote ii) Hyper iii) Iso

Answer 104

It is a comparative study between two solutions or environments. This relationship is very important for ## Footnote the normal functioning of all the cells. The cells react in the following manner in the following environments: – Isotonic: cell neither shrinks nor swells – Hypertonic: cell shrinks (crenation) – Hypotonic: cell swells (hemolysis) **.9% NaCl is best tonicity for animal cells**

Answer 105

Molecular movement still taking place ## Footnote * Thus equal movement of solute in both directions * Therefore no net movement of solute * Solution is homogenous at equilibrium (concentration of solute equal throughout the solution)

Answer 106

\* Active transport - energy \* secondary active transport or cotransport - energy \* Bulk tansport - endocytosis (phagocytosis, pinocytosis, receptor mediated endocytosis) and exocytosis

Answer 107

ATP is needed. Movement of a substance across the plasma membrane, against the ## Footnote concentration gradient. Example: Na/K pump (2 potassium in)

Answer 108

Here one molecule provides the Energy for moving the other ## Footnote molecule. Ions or molecules move in the same (symport ie Cotransport –Na+ & Glucose ) or different (antiport – Na+ & K+) direction. 1. A sodium-potassium pump maintains a concentration of Na+ higher outside the cell 2. Na+ moves back into the cell by a carrier protein (by facilitated diffusion) that also moves glucose. The concentration gradient for Na provides the energy required to move glucose against the concentration gradient.

Answer 109

Ingests substances through the formation of vesicles. Here there is ## Footnote movement of large substances across the plasma membrane into the cell by means of membrane invagination (vesicles).

Answer 110

cell eating. Surrounding of solid substance by PSEUDOPODS of cell membrane and ## Footnote drawing it into cell. Example WBC

Answer 111

Cell drinking Movement of fluid droplets into the cell by means of cell invagination.

Answer 112

specific receptor on the membrane allowing for endocytosis

Answer 113

Exiting of substances from the cell through fusion of secretory vesicles ## Footnote with membrane. This process requires following – Pinching of vesicles – energy since it is a type of an active transport – Examples of Exocytosis are: -- Secretion of digestive enzymes by pancreas -- Secretion of mucous by salivary glands -- Secretion of milk by mammary glands

Answer 114

• Lipid soluble molecules – pass through the phospholipid bilayer ## Footnote * Large water soluble molecules- use carrier proteins * Small water soluble molecules- use membrane channel

Answer 115

a. hypotonic b. out of the cell c. faciliated diffusion (high concentration to low concentration) d. no energy needed

Answer 116

a. active transport b. yes c. F

Answer 117

a. cotransport with carrier protein ? b. yes c. ?

Answer 118

The cytoplasm is the fluid found between the nucleus and the plama membrane. It is the site of most of ## Footnote the chemical reactions of the cell. The cytoplasm is made up of Cytosol, Cytoskeleton, Cytoplasmic Inclusions(chemical molecules), Organelles. An organelle is a small structure that has a specific function.

Answer 119

• fluid portion ## Footnote * Has dissolved molecules ( like ions in water) * Has colloids (like proteins in water)

Answer 120

– Microtubules: hollow, made of tubulin protein(total 9 & are arranged in sets of 3). ## Footnote • Function: Internal scaffold(support structure), transport, cell division – Microfilaments: actin protein. • Fucntion: Structure, support for microvilli, contractility, movement – Intermediate filaments: keratin protein mechanical strength

Answer 121

• chemicals ## Footnote • EX lipid droplets, melanin etc

Answer 122

• Small ## Footnote * Have specific structure * Perform specific function * Most organelles have membranes that separate interior of organelles from cytoplasm

Answer 123

Most numerous of all organelles and the site of protein synthesis, each consist of 2 subunits. These are ## Footnote produced within a special structure of the nucleus called the NUCLEOLUS and they move into the cytoplasm once they are formed. These are the site for protein synthesis. They are made of a large and a small subunit. Ribosomes are of 2 types: Free and attached (attached to Rough Endoplasmic Reticulum)

Answer 124

The outside plasma membrane is continuous with a series of channels inside of the cell called ## Footnote • Types – Rough Endoplasmic Reticulum (RER) * Has attached ribosomes * Function - Proteins produced and modified here and later shipped to the Golgi. – Smooth Endoplasmic Reticulum (SER) • No attached ribosomes

Answer 125

– Interior spaces of the ER and isolated from the rest of cytoplasm

Answer 126

It stores, modifies, packages and distributes proteins and lipids for secretion or for the cell’s own use. ## Footnote Found especially in cells that secrete material to the outside Ex. cells that are involved with making mucus or hormones). Golgi Apparatus has Cisternae which are flattened membrane sacs stacked on each other.

Answer 127

Round structures that are found in the cytoplasm, and that contain hydrolytic digestive enzymes. These enzymes are able to digest material endocytized. In addition, they are responsible for autophagiadigesting organelles in the cell that are no longer functional. Also important in normal development formation of digits during gestation. Actually occurs when cells in the webbed fingers and toes of fetus produce a lot of lysosomes and they burst and destroy the web tissue. This is known as APOPTOSIS.

Answer 128

They smaller than lysosomes. They contain enzymes that break down fatty acids and amino acids into hydrogen peroxide. The hydrogen peroxide is then broken down by CATALSE enzyme into water and oxygen.

Answer 129

Consist of large protein enzyme complexes that break down and recycle proteins in the ## Footnote cell

Answer 130

Organelles found in cytoplasm, especially in metabolically active cells. Surrounded by 2 membranes. Cristae is the infoldings of the inner membranes. Matrix is the substance located in the space that is enclosed by the inner membrane. They produce the high energy molecule, ATP ( adenosine triphosphate). Sometimes they are referred to as the POWERHOUSE of the cell. Mitochondria increase in number when energy requirements increase. Mitochondria contain their own DNA that codes for some of the proteins needed for mitochondria production.

Answer 131

Organelles that occur in pairs in animal cells. They are located in Centrosome (space). The are found at right angles to each other and are actually shaped like cylinders made out of 27 microtubules (ie 9 triplet tubules). Right before cell division, the Centrosome and the centrioles divide, move towards ends of the cell and help organize the spindle fibers

Answer 132

Only found on some cells. ## Footnote A) CILIA: small hair-like structures that project from cell surfaces and will transport material over the cell surface. Ex: present in oviducts and Trachea. B) FLAGELLA (um) Long hair-like extension. Usually one per cell. It produces a wave like motion and is responsible for mobility of cell. Only human cell with flagellum = sperm.

Answer 133

This is a round structure found in eukaryotic cells at some point in their development. ## Footnote There is usually 1 per cell. However, in very active cells such as some muscle cells, they may be MULTINUCLEATED. The human red blood cell will not have a nucleus when mature and circulating in the blood, but will have had one during its development The nucleus is surrounded by a double membrane (nuclear envelope)and is the site that contains the genetic message of the cell. NUCLEAR PORES allow for passage of material into and out of the nucleus. There is a NUCLEOLUS inside of the nucleus where RIBOSOMES are produced. It alsocontains Nucleoplam.

Answer 134

• Interphase ## Footnote – G1 – S – G2 – G0 * Mitotic Phase * Interphase

Answer 135

– Karyokinesis– Nuclear Division: Mitosis – Somatic Cells & Meiosis - Gametes – Cytokinesis - Cytoplasmic Division

Answer 136

There are 2 types of nuclear divisions that can occur in the human body - mitosis and meiosis. • Meiosis- – Gametes – Reduction division – Daughter cells different than parent cells – reproduction • Mitosis – Somatic Cells – Multiplication Division (Doubled & then Halved) – Daughter cells same as parent cell – Repair, growth, development

Answer 137

DNA ## Footnote – 23 pairs of chromosomes – Present in nucleus • Chromosome – In nucleus – Contains genes • Gene – Hereditary unit of a cell – Present on a Chromosome

Answer 138

arranging chromosomes from both parents on the basis of size and shape

Answer 139

postion of a gene on the chromosome

Answer 140

different forms of a gene

Answer 141

same shape and size chromosome coming form both ## Footnote parents

Answer 142

1. PROPHASE: chromosomes 2. METAPHASE: sister chromatids 3. ANAPHASE: daughter chromosomes 4. TELOPHASE: cleavage furrow; daughter chromsomes

Answer 143

* Mitosis conserves the number of chromosome sets, producing cells that are genetically identical to the parent cell * Meiosis reduces the number of chromosomes sets from two (diploid) to one (haploid), producing cells that differ genetically from each other and from the parent cell * The mechanism for separating sister chromatids is virtually identical in meiosis II and mitosis

Answer 144

Three events are unique to meiosis, and all three occur in meiosis l. These don’t happen in Mitosis: ## Footnote – Synapsis and crossing over in prophase I: Homologous chromosomes physically connect and exchange genetic information – At the metaphase plate (I), there are paired homologous chromosomes (tetrads), instead of individual replicated chromosomes – At anaphase I, it is homologous chromosomes, instead of sister chromatids, that separate

Answer 145

* \*\*Meiosis has two nuclear divisions. In terms of names it is like going through mitosis twice (i.e., interphase I, prophase I-telophase I, interphase II, prophase II-telophase II). * Similarity of meiosis to mitosis are as follows (these stages are most alike): * --interphase and interphase I * --prophase and prophase II * --metaphase and metaphase II * --anaphase and anaphase II * --telophase and telophase II

Answer 146

• Cellular clock. After a certain amount of time or certain number of cell divisions, cells die. ## Footnote * Death genes. Turn on late in life, or sometimes prematurely causing cells to deteriorate and die. Apoptosis(caused by lysosomes). * DNA damage. Telomeres at ends of chromosomes TTAGGG. During replication, nucleotides are lost. Telomerase enzyme ( protects telomeres) seem to be lost with aging. * Free radicals. DNA mutation is caused by free radicals (atoms or molecules with an unpaired electron that try to complete their shells by snatching e- from other healthy cells, thus destroying those cells. * Mitochondrial damage. Mitochondrial DNA is more sensitive to free radicals. Loss of ATP energy, cell death seen

Answer 147

The chromosomes are composed of DNA molecules. In order to get the exact replica of a cell when it undergoes mitosis, the DNA must be copied. DNA = deoxyribonucleic acid, a large molecule that is made up of 2 backbones of deoxyribosen ( a sugar) and phosphate group that alternate with each other. Sticking out of these backbones, like the rungs on a ladder, are a series of bases. The 4 possible bases for DNA are: adenine (A), thymine (T), guanine (G), and cytosine (C). These bases go through COMPLIMENTARY BASE PAIRING = A-T and G-C. These are held together by hydrogen bonds. This DOUBLE HELIX structure, which resembles a spiral staircase. The signiuficance is that the diameter remains consistent throughout the molecule.

Answer 148

• Internal & External Cell Cycle Controls are lost ## Footnote * Cancer cells make their own growth factors * Cells divide excessively * Cancer develops * normal cell converted to a cancerous cell by Transformation process * Cancer cells form masses of abnormal cells called Tumors within a normal tissue * If abnormal cells remain at the original site, the lump is called benign tumor * Malignant tumors invade surrounding tissues and can metastasize, – Metastasize means exporting cancer cells to other parts of the body to form secondary tumors by the help of: • a) Blood vessels • b) Lymphatics

Answer 149

* Single stranded * Structure – Sugar-Ribose – Phosphorus Group – Nitrogen base pairs * Guanine – Cytosone * Adenine - Uracil * There are 3 types of RNA = messenger RNA (mRNA), transfer RNA (tRNA) and ribosomal RNA (rRNA).

Answer 150

Occurs in the nucleus; making of RNA from DNA ## Footnote 1. A portion of the DNA molecule (bubble) opens up (not the complete molecule as on replication) and in that portion only 2. the bases are exposed. 3. RNA Polymerase reads bases on DNA (in3’-5’ direction) and supplies bases to mRNA strand. (RNA nucleotides within the nucleus line up with complementary bases on an opened area of the DNA on ONE STRAND ONLY.) 4. mRNA detaches from DNA and is further processed (cap and tail added) 5. mRNA leaves nucleus (nuclear pore) 6. mRNA enters cytoplasm 7. DNA bubble closes

Answer 151

* mRNA in cytoplasm now * Attach to ribosome (rRNA) * Ribosome reads mRNA (in CODONS from 5’-3’direction ie opposite to direction in which DNA is replicated) * CODONS – Nitrogen bases in sets of 3, coding for 1 amino acid (a. acids in cytoplasm) present on mRNA * 1 Start CODON: AUG (code for A.Acid Methionine) * 3 Stop CODON - UAA, UAG, and UGA (codes for nothing) * tRNA (clover leaf shaped) present in cytoplasm & has 2 ends – One end- specific amino acid – Other end – anticodon (anticodon is complimentary base pair that is paired with the * tRNA brings amino acids to the ribosome (that has mRNA attach to it) * Once a. acid is in place , tRNA detaches from a. acid and looks for more a. acid (cycle goes on…) codons on mRNA)

Answer 152

* For example, the DNA sequence is T A C * Now the mRNA codon is A U G * Therefore the tRNA anticodon will be U A C * Thus the Amino Acid for protein reads A U G (start codon- methionine)

Answer 153

* Human mRNA sequence is introduced into bacterial DNA sequence (in the lab) * Bacterial DNA is then programmed to express human proteins * This type of DNA is called recombinant DNA (new type or new combination) * This process is called Genetic Engineering * Ex: Previously, Diabetics injected with insulin - derived from cows and pigs * Recently, Diabetics injected with insulin – (also called Humulin) derived from genetically engineered E. coli)

Answer 154

* Genetic code (A. Acids codes) is universal for all organisms (whether animal or plants)ie using the same base pair rules but the sequencing is different. So, bacteria will have base sequences that code for bacteria protein and humans will have bases arranged that code for human proteins. * All somatic cells have same genetic code (whether skin, liver or hair cells) • But cells are different from each other and produce different proteins because certain genes are turned off in certain cells.

Exam 1 Flashcards

(208 cards)