DNA replication and DNA damage Essay

Biology Review and Study Guide Cell Division and Cancer Cells divide for two main reasons: first, the larger a cell becomes, the more demands the cell has on its DNA. Second, a large cell has more trouble moving enough food in and enough waste out. Before it becomes too large, a growing cell divides. The two new cells are referred to as daughter cells.

The process by which a cell divides into two cells is called cell division. Mitosis is part of the eukaryotic cell cycle during which the nucleus divides. Cytokines is part of the eukaryotic cell cycle during which the cytoplasm divides. A genome is an entire set of genetic information that an organism carries in its DNA. Chromatin: one of two identical “sister” parts of a replicated chromosome.

Chromosome: a threadlike structure that contains genetic information that is passed from one generation of cells to the next Somatic cells: any cell of a living organism other than the reproductive cells Sister chromatics: two identical copies of a single chromosome that are connected by a centimeter Centimeter: an area where two sister chromatics are attached Connectors: an organelle near the nucleus of a cell hat contains the centurions (in animal cells) and from which the spindle fibers develop in cell division Cleavage furrow: is an acting rich “purse sting” that draws tight to separate daughter cells to complete cytokines in cell division The cell cycle is a series of events a cell goes through as it grows and divides.

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During the cell cycle, a cell grows, prepares for division by making a copy of its DNA, and then divides to form two daughter cells. Each daughter cell then begins the cycle again. A) Prokaryotic cell cycle: includes cell growth, DNA replication, and cell division. The process of cell division in prokaryote is a form of asexual reproduction called binary fission. B) Eukaryotic cell cycle: includes four phases (enterprise) GIG, S, 62, and M. GIG : Cell growth-cell increases in size and produces new proteins and organelles (GO: Non-replicating cells are found in a stage of the cell cycle called GO. These cells may be quiescent (dormant) or senescent (aging or deteriorating.

Cells may remain quiescent in GO for an indeterminate period of time (when no more new cells are needed), only to re-enter GIG phase and begin dividing again under specific conditions. While quiescent cells may re-enter the cell cycle, senescent cells do not. S: DNA Replication-new DNA is “synthesized” when chromosomes are replicated 62: Preparing for Cell Division- many of the organelles and molecules needed for cell division are produced; at the end of 62, a cell is ready to divide. M: Cell division- Mitosis is divided into four phases: Proposes-the nuclear envelope breaks down, and a spindle begins to form. A pair of structures called centurions help to organize the spindle fibers.

Metastases- chromosomes line up at the center of the cell; spindle fibers connect the centimeter t each chromosome to the spindle Anapest-sister chromatics separate and move apart; chromosomes move to opposite ends of the cell Telephones- a nucleus forms around each set of chromosomes, then cytokines occurs Cytokines- a) animal cells: the cell membrane pinches in b) plant cells: a cell plate forms Checkpoints (there are 3) control the cell’s progress through the cell cycle, and ensure that key processes such as DNA replication and DNA damage repair are completed before the cell cycle is allowed to progress into the next stage. Checkpoints also ensure that tot daughter cells receive the same number of chromosomes and that daughter cells are genetically identical to the parents.

Difference between: * Centimeter: an area where two sister chromatics are attached Connectors: an organelle near the nucleus of a cell that contains the centurions (in animal cells) * Sex chromosome: chromosomes, differing in shape or function from other chromosomes, that determines the sex of an individual; usually designated X or Y, in the germ cells of most animals and some plants, that combine to determine the sex and sex-linked heartsickness of an individual, with XX resulting in a female and XX in a male in mammals. Outcomes: chromosomes that do not determine sex * Homologous chromosomes: chromosome pairs, one from each parent, that are similar in length, gene position and centimeter location Sister chromatics: two identical copies of a single chromosome that are connected by a centimeter * Haploid: term used to refer to a cell that contains only a single set of genes Diploid: term used to refer to a cell that contains two sets of homologous chromosomes Cancer the disease caused by an uncontrolled division of abnormal cells in a part of he body.

Benign tumors (non-cancerous) are a mass of cells (tumor) that lacks the ability to invade neighboring tissue or metastasis (spread to others parts of the body) Malignant tumors (cancerous) are made up of cells that grow out of control and can invade nearby tissues and spread to other parts of the body. Cancer cells are basically normal cells that have been damaged and did not respond properly to the damage. They exist in a constant state of division and ignore the usual cell cycle checkpoints that a normal cell will go through in its division cycle, often resulting in a moor consisting of tightly packed bunches of cancer cells that continue to divide. Normal cells check for a variety of factors including DNA integrity and availability of space and resources. Metastasis is a complex process that involves the spread of a tumor or cancer to distant parts of the body from its original site.

Stem cells are capable of dividing and renewing themselves for long periods; they are unspecified; and they can give rise to specialized cell types. Two types- embryonic stem cells and adult stem cells Cell differentiation-when a cell goes from unspecified to a specialized cell DNA Replication DNA is a double helix formed by base pairs attached to a sugar-phosphate backbone. DNA strands nave a directional TTY, and the deterrent ends tot a single strand are called the “3′ (three-prime) end” and the “5′ (five-prime) end”. By convention, if the base sequence of a single strand of DNA is given, the left end of the sequence is 5′ end, while the right end of the sequence is the 3′ end. The strands of the double helix are anti-parallel with one being 5′ to 3′, and the opposite strand 3′ to 5′.

Charges rules state that DNA from any cell of all organisms should have a 1:1 ratio (base Pair Rule) f pyridine and Purina bases and, more specifically, that the amount of guanine is equal to cytosine and the amount of adenine is equal to thymine. The standard arrangement of bases in nucleotides in relation to their opposite pairing, such as thymine being paired with adenine and cytosine paired with guanine. It is semi- conservative because when DNA replicates, a new strand is made based on the original strand. DNA replication is the process of copying DNA prior to cell division. It makes sure that each daughter cell has the same complete set of DNA molecules. A)

The DNA molecule first separates into two strands b) The process then makes two new strands following the rules of base pairing (Adenine + Thymine, Guanine + Cytosine) c) Each strand of the double helix of DNA is a model for making the new strand Prokaryotic DNA Replication- replication starts from a single point , and continues in two directions until the whole chromosome is copied Eukaryotic DNA Replication-replication may begin in hundreds of places on the DNA molecule Replication fork: A Y-shaped region in a chromosome that serves as a growing site for DNA replication, and occurs in both direction until each horseshoe is completely copied Replication bubble: A DNA replication bubble occurs during the replication process. As the double stranded DNA (adds) is unwound, a replication bubble forms.

At the bubble, a replication complex forms, and the DNA replicates in both directions, causing a replication fork Origin of replication: regions of the DNA that are necessary for its replication to begin Helices: enzymes that unwind and separate double-stranded DNA or RNA during its replication dent: an NTP is a nucleotide troposphere, or the basic building block of RNA and is used by DNA polymerase to add nucleotides to the elongating DNA strand. NNTP are similar to Nntp, but are made up of didgeridoos rather ribose. DNA polymerase Ill: an enzyme that has different functions, such as: proofreading newly replicated DNA, removing nucleotides from 3′ end of the strand one by one, and binding nucleotides from 5′ end of the strand.

Single-stranded DNA binding protein: proteins responsible for holding the replication fork of DNA open while polymerase read the templates Topographies: any of a class of enzymes that reduce super oiling in DNA by breaking and rejoining one or both strands of the DNA molecule Aliases: enzymes that are used like glue to hold DNA together after replication Kaki fragments: little fragments of freshly made DNA Leading strands are strands that are synthesized in the 3′ to 5′ format discontinuously while the lagging strand is synthesized from 5′ to 3′ continuously. Leading require a RNA primer, lagging strand does not, and they have different polymerases for their elongation. Telemeter- repetitive DNA at the end of a eukaryotic chromosome. DNA in these regions are hard to replicate. Cells use a special enzyme called telemeters, which makes it less likely that genes will be damaged or lost during replication of rapidly dividing cells. It is often switched off in normal adult cells, but in cancer cells, telemeters may be switched on, and may be one tot reasons why cancer cells are able to grow and divide rapidly. Circulatory System, Respiratory System, & Gas Exchange 1 .

Astrological cavity: a digestive chamber with a single opening Open circulatory system: blood is only partly contained within blood Closed circulatory system: blood circulates entirely within blood vessels 2. Vertebrate cardiovascular system: includes a heart and a series of blood vessels Double circulation- type of blood circulation system in which the blood flows through the heart twice 3. Mammals have a four- chambered heart. The right atrium gets oxygen-poor blood from the body. The right ventricle pushes the blood to the lungs. The left atrium get oxygen-rich blood from the lungs. The left ventricle pushes oxygen-rich blood out to the rest of the body. (Oxygen-rich and oxygen-poor blood cannot mix. ) 4.

The cardiac cycle is the cycle of events that occurs as the heart contracts. The cardiac cycle consists of two phases, the diastole phase and the systole phase. In the diastole phase, the heart ventricles are relaxed. The valves located between the atria and ventricles are open, allowing blood to flow through to the ventricles. In the systole phase, the ventricles contract and pump blood to the arteries. The right ventricle sends blood to the lungs via the pulmonary artery while the left ventricle pumps blood to the aorta. Pacemaker: 1 . A small group of cardiac muscle fibers, (AS node) found in the right atrium, which sends an electrical pulse to the atria, and they contract. A device that’s placed in the chest or abdomen to help control abnormal heart rhythms & uses electrical pulses to prompt the heart to beat at a normal rate. Blood vessels: a tubular structure carrying blood through the tissues and organs a) Arteries: a large blood vessel that carries blood away from the heart to the tissues of the body b) Capillary: the smallest blood vessel that brings nutrients and oxygen to the tissue and absorbs carbon dioxide and waste products c) Vein-a blood vessel that carries blood from the body back to the heart Blood pressure: force of blood against the walls of your blood easels 5. Blood carries oxygen, helps your body fight against disease, maintaining body temperature, and carries sources of energy such as sugars and fats.

The structure of blood includes plasma and blood cells (red blood cells or erythrocytes, white blood cells or leukocytes and blood platelets or thromboses) 6. Gas exchange: How- oxygen and carbon dioxide diffuse cross the thin walls of alveoli and capillaries Why is it important-supplies oxygen for cellular respiration and disposes carbon dioxide. 7. Respiratory surfaces: part of an animal where gases are exchanged with the environment Types: Skin: can be used as a respiratory surface but it does not have much surface area compared to lungs or gills and it must remain moist to function in gas exchange. (9. ) Gills: provide a large surface area for gas exchange in aquatic organisms. The flow of blood in the gills of fish is in the opposite direction that water passes over the gills.

This arrangement (called counterculture flow) enables fish to extract more oxygen from the water than if blood moved in the same direction as the passing water. Gills cannot be used in air because they lack tutorial support; they would collapse. Tracheae are a network of tubules that bring oxygen directly to the tissues and allow carbon dioxide to escape. The openings to the outside, called spiracles, are located on the side of the abdomen. Lungs: organs that exchange oxygen and carbon dioxide between b and air. Animals that breathe with lungs inhale air at the surface and hold their breath underwater. 8. Respiratory medium: source of oxygen 10. The respiratory system picks up oxygen from the air we breathe in.

It releases carbon dioxide back into the air when we breathe out. Structures: Nose: where air is filtered, moistened, and warmed before entering the lungs Pharynx: a tube at the back of the mouth that serves as a passageway for both air and food Larynx: a structure in the throat that contains the vocal cords Trachea: a tube that connects the larynx to the bronchi; also called the windpipe 1 1 . Surfactant: a substance that tends to reduce the surface tension of a liquid in which it is dissolved Negative when the diaphragm expands, increasing the volume of the chest cavity which decreases the pressure within so then the air rushes down the trachea.


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