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what is a protoplasm?
a thick viscousm, suspension substance that constitutes the physical basis of all living activities
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what are the properties of a cell?
- assimilation
- growth
- motility
- secretion
- irritability
- reproduction
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simple life forms consist of how many type of cells?
one
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more complex life forms are made up of how many types of cells?
many types of cells
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what is a tissue?
- groups of cells that perform the same activity
- epithelial, connective, muscular and nervous
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what is an organ?
- groups of tissues that perform a specialized function
- stomach- composed primarily of epithelial and muscle tissue
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what does a group of organs form?
- a system
- GI or respiratory system
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what is the highest level of organization?
a person or bird
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what are organic compounds?
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what are inorganic compounds?
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which one, organic or inorganic compound, is suspended or dissolved in water?
both
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a cell is made up of how much water?
80%
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what are the roles of water in a cell?
- helps hold and transport substances in the cell
- chemical activities take place in the cell
- helps maintain constant temperature
- w/o water, cells would be vulnerable to extreme changes in temperature
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how does a cell move water in and out?
- by osmosis
- amount determined by osmotic pressure
- osmotic pressure determined by the concentration of mineral salts inside or outside of cell
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what happens when there's too much or too little water in the cell?
- too much- cell ruptures
- too little- cell collapes
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what happens when there's too little sodium inside the cell or too little potassium outside the cell?
will cause water to be pulled outside the cell causing collapse
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what is hypertonic?
a solution that causes a cell to shirnk
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what is hypotonic?
a solution that causes a cell to swell
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what is isotonic?
having an osmotic pressure equal to that of circulating blood
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what are the benefits of mineral compounds and salts?
- minerals prevent cramping
- salts aide in the production of energy and the conduction of nerve impulses
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what are the major classes of organic compounds?
- proteins
- lipids
- carbohydrates
- nucleic acids
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what are proteins?
- macromolecules-polymers
- large molecules formed by joining together simple units known as monomers into a long chain
- building block of a cell
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protein makes up how much in a cell?
15%
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a protein is important to which types of tissues?
- structure of skin
- bone
- tendons
- ligaments
- hair
- silk
- collagen
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what are the functions of proteins?
- building new tissue
- repair injured or broken down tissue
- intercellular messengers
- composition of enzymes
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what are enzymes?
large protein molecules that control the speed of most chemical reactions inside the cell
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what are amino acids?
- basic composition of proteins
- about 80 are found, 20 are essential to humans
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the more specialized the cell is it is more resistant or nonresistant to radiation?
resistant
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what is hemolysis?
too much water can rupture cell
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what are lipids?
- fats
- make up about 2% of a cell
- excess energy is stored for later use
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how do lipids form?
sugar molecules, from which cells usually get their energy, are converted into lipids for storage if not needed for current use
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are lipids water soluble?
- no
- but are in alcohol, ether, oil and chloroform
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what are the classifications or types of lipids?
- those stored in the inside the cell for energy
- those used to form the cell membranes as a thermal cushion
- also for production of steriods, cholesterol, testosterone, and estrogen
- long chain lipids important for pigmentation such as eye color
- involved with muscle contraction, blood vessel constriction, cell reproduction, and inflammatory response
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what are the functions of lipids?
- storage of energy
- important component of cell membrane
- protection against cold and heat
- assistance in digestive process
- components of substances such as hormones
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what are carbohydrates?
- make up about 1% of the cell
- provide most of the cell's' energy
- sugars and starches are typical carbohydrates
- stored primarily in the liver and muscles
- they release large amounts of energy when the bonds are broken through metabolism
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what are the classifications of carbohydrates?
- monosaccharides
- disaccharides
- polysaccharides
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what are monosaccharides?
- glucose or fructose
- primary source of cell energy
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what are disaccharides?
- sucrose, lactose, and maltose
- not easily metabolized
- storage form of energy that can be converted to glucose and used for energy requirements
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what are polysaccharides?
- starch, dextrin, cellulose and glycogen
- used as an energy source
- cellulose is used for structural purposes
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what are nucleic acids?
- macromolecules
- blueprint for reproduction
- a template for protein synthesis
- transport mechanism to join materials necessary to build proteins
- control mechanism to regulate the cell's metabolism and reproduction
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what are the two types of nucleic acids?
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what are the two major sections of the cell?
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are both cytoplasm and the nucleus covered with protoplasm?
- yes
- nucleoplasm- protoplasm inside the nucleus
- cytoplasm- protoplasm outside the nucleus
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what are the structures within the protoplasm called?
- organelles
- each organelle has a function necessary for cell health and survival
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what does the nucleus contain?
- the genetic and metabolic information of the cell
- similar to the brain of the organism
- this controls how that organism functions in its environment
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what are the components of the nucleus?
- nuclear envelope
- chromosomes
- nucleolus
- nuclear sap- the liquid portion of a cell nucleus
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what is the nuclear envelope?
- membrane that separates the nucleus from the cytoplasm
- double-walled structure with a space within the walls
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which structures are the only ones that can pass through the nuclear envelope?
- RNA's
- some proteins that are incorporated into the nuclear structure
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what are chromosomes?
linear threads in the nucleus
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what are chromosomes composed of?
- proteins and DNA
- DNA encodes the information that controls that cell's metablosim and reproduction
- DNA is considered the genetic material and serves as a template to produce an exact copy of itself used in cell division
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how many chromosomes do humans contain?
46 (23 pairs)
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A DNA structure contains what?
- deoxyribose- sugar in the backbone
- phosphoric acid- a phosphate in the backbone
- Four introgenous bases- the actual genetic code
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what are the four nitrogenous bases within a DNA?
- adenine
- guanine
- thymine
- cystosine
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what does a DNA look like?
- a twisted ladder
- the bases are the rungs
- the backbones are the sides
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what are the backbones of a DNA made of?
- sugar
- deoxyribose
- phosphoric acid
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what are genes?
- the basic unit of heredity
- made up of long squences of DNA on a chromosome
- genes are found in pairs
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what do genes accomplish?
- some govern the number of organs and limbs
- others determine heigh, skin and eye color and gender
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what is a nucleolus?
a single spherical structure usually found in the nucleus
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what is the nucleolus composed of and what does it do?
- composed of RNA(ribonucleic acid)
- controls protein synthesis
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what are the similarities and differences of a nucleolus and a DNA?
- similar structure to DNA
- nucleolus' sugar is ribose as opposed to deoxyribose
- the base uracil replaces thymine
- it is a single helix
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what are the forms of RNA?
- messenger RNA
- transfer RNA
- ribosomal RNA
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what does a messenger RNA do?
carries the code for specific amino acid sequences from DNA to cytoplasm for protein synthesis
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what does a transfer RNA do?
transfer amino acid groups to ribosome for protein synthesis
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what does a ribosomal RNA do and where does it live?
- exists in the ribosomes
- thought to assist in protein synthesis
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where do metabolic functions such as anabolism and catabolism occur?
- cytoplasm
- these functions are used in energy conversion and serves to store or release energy
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what is anabolism?
the duplication of DNA, production of hormones, and converting of sugars to starches
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what is catabolism?
the breaking of the carbon-hydrogen bond to release the energy of glucose
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what does the cell membrane consist of and what does it do?
- composed of lipids and membranes
- transport proteins assist in the passage of substances through the membrane and throughout the cell
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what are ribosomes and what are they made of?
- function to synthesize proteins
- made of ribosomal RNA
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what is the endoplasmic reticulum and what does it do?
- a connecting netweork between the nucleus and cytoplasm
- used to build carbohydrates and lipids and detoxification
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what is the mitochondria and what does it do?
the source of energy in the cell
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does a mitochondria contain their own dna?
yes
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which muscle cells have the greatest number of mitochondria because of their great need for energy?
cardiac muscle cells
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what is the golgi apparatus and what does it do?
- located near the nucleus
- collect molecules produced in one part of the cell, modify, or syntesisze new molecules, package and distribute them to other parts of the cells
- analogous to the digestive system
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what are lysosomes?
- part of the intracellular digestive system
- break down proteins, carbohydrates, lipids, and nucleic acids and recycle them
- analogous to the stomach
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what is mitosis?
- cell division of smatic cells
- each daughter cell contains the same number of chromosomes as the parent cell
- a cycle that has 5 phases, 4 are cell-reproduction phases
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what are the 5 phases of mitosis?
- interphase
- prophase
- metaphase
- anaphase
- telophase
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what happens during interphase?
- the period between cell division
- has 3 subphases
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what are the 3 subphases of interphase?
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what is the G1 subphase?
the first subphase where the cell spends most of its life and where it grows
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what is the S phase?
the DNA is replicated but stays attached to the centromere, a region in the middle of each chromosome
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what is the G2 phase?
- the final subphase in which the organelles are reproduced
- spiral filaments called chromatids reproduce
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what happens during prophase?
- the chromatin granules of the nucleus become organized into chromosomes
- each consist of two chromatids
- chromosomes become shorter and more compact
- the nuclear membrane and nucleoli disappear, the centriole divides, and two daughter cells move to opposite poles of the cell
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what happens during metaphase?
- the paired chromatids arrange themselves in an equatorial plane midway between the two centrioles forming the plane
- cell division can be stopped and radiation damage can be examined under a microscope
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what happens during telophase?
- each daughter cell now contains the same genetic material as the parent cells
- two complete cells results from the cytoplasm's becoming separated into two parts
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what is meiosis?
cell division that produces germ cells or reproductive cells
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how many successive divisions of the mother cell occur in meiosis and how many daughter cells are produced?
- 2 divisions
- 4 daughter cells
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how many chromosomes are passed down in meiosis?
only half the number compared in somatic cells
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compare malignant cells to normal cells
- bigger nucleus
- small cytoplasm
- increase mitotic activity (division)
- in normal tissue, cells usually stick together
- some types of cancers metastasize by allowing cells to break free of the tumor site
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