Having the same genes in a pair; identical alleles
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What is Heterozygous?
having unlike genes in a pair; two different alleles
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What is a Phenotype?
An expression of genes present; physical traits
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What is a Genotype?
the actual genes present
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List 3 characteristics of early awareness of inheritance.
1. traits are passed from parents to offspring 2. Artificial selection was practiced by farmers 3. today we have clear understanding of the nature of genes and the scientific basis for selective breeding
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List 4 characteristics of Genes.
1. hereditary material (DNA) found in chromosomes 2. organized in units (a segment of DNA molecule) 3. Each gene codes for the formation of one protein 4. Genes control all phases in the life of an organism
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Where do genes occur?
chromosomes (at a specific location); on the homologous chromosome, there is a second gene for the same trait at the same location
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What are Homologous chromosomes?
look alike and carry genes for the same traits
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What are Gametes?
haploid and contain 1 of each homologous chromosome
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What happens to the zygote?
receives one haploid set of chromosomes from egg and one set from the sperm
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For any genetic trait, organisms have 2 genes. It will receive...
one gene on a specific chromosome from one parent and another gene for that same trait on the homologous chromosome from the other parent
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What are Alleles?
1. alternate forms of a genes 2. gene that controls flower color may have alleles that specify purple or white flowers
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What are dominant traits?
Each trait one allele generally masks/is dominant over the other
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What are recessive traits?
non dominant allele
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Who is the father of genes?
Gregor Mendel (19th century); Augustinian monk who lived and worked in an Austrian monastery
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Why was Mendel's work ignored?
it was no mainstream; too brilliant; hard to understand
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Summarize Mendelian Genetic findings.
experiments with garden peas that demonstrated the principles of heredity; garden peas easy to work with (self pollinate but easy to cross)
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List the 7 contrasting pairs of traits from Mendel and the Garden Pea.
Mendel selected seven contrasting pairs of traits: Tall versus dwarf plants Yellow versus green seeds Round versus wrinkled seeds Green versus yellow pods Inflated versus constricted pods Purple versus white flowers Terminal versus lateral flowers
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What is monohybrid crossing?
Mating individuals that differ in only one trait
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What was the offspring of the cross called, and what did they produce?
F1 generation, or first filial generation; produced yellow seed
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F2 generation, or second filial generation
1. Approximately 3/4 yellow and 1/4 green 2. 3:1 ratio
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What are the 3 Molecular basis of heredity?
1. how traits are passed from one generation to another 2. Understanding nucleic acids and what they do 3. explains how genes function
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What are Nucleic Acids?
chemical compounds composed of repeating units called nucleotides
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List 3 basic units of the DNA molecule.
1. one sugar (either ribose or deoxyribose) 2. one phosphate group (PO4) 3. one nitrogenous base
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List the 2 Nitrogen (Purine) bases
*adenine (A) *guanine (G)
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List the 3 Nitrogen (Pyrimidine) bases
*cytosine (C) *thymine (T) only in DNA *uracil (U) only in RNA
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What is DNA?
*hereditary material *sequence of the bases in DNA makes up the genetic code *often called the double helix (double stranded molecule twisted into a helix) *Pairs of bases extend across A=T, G=C
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What are the sides of a DNA helix composed of?
sugars and phosphates
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What is RNA?
*Single stranded *manufacture of proteins by carrying out the instructions coded on the DNA molecule
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What are the differences between RNA and DNA?
1. DNA is Double stranded while RNA is Single Stranded 2. DNA is a double helix while RNA is a single helix 3. DNA has Deoxyribose sugar while RNA has ribose sugar 4. DNA stores and transmits genetic information while RNA acts as a template for making proteins. 5. DNA is found in the nucleus only. RNA is found everywhere in the cell 6. There is only one kind of DNA. There are three kinds of RNA--tRNA, mRNA, rRNA
synthesis of an RNA molecule from a DNA template: 1. mRNA carries information for a protein out to the cytoplasm 2. mRNA attaches to a ribosome
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What does the DNA do during transcription?
1. part of DNA molecule unwinds 2. One strand serves as template for synthesis of mRNA 3. molecule of DNA rewinds and mRNA leaves the nucleus
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What are 4 characteristics of Genetic Code?
*Every 3 bases on the RNA is called a codon *Each codon specifies an amino acid *universal *In the cytoplasm, the mRNA attaches to a ribosome
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What is a Translation?
1. mRNA molecule is translated into a protein 2. mRNA molecule is read codon by codon to form a chain of amino acids 3. Amino acids are carried to the ribosome by tRNA
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What happens to the amino acid as the mRNA is translated?
the amino acid chain elongates
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What are 3 characteristics of the Universal Code?
*Genetic code and protein synthesis is the same in all living organism *One organism can understand the genetic instructions of another organism Universal code *Using tools of genetic engineering scientists can transfer genes from one organism to another
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What classifies as a macronutrient? (3)
carbohydrates, proteins, and fats (required in large amounts)
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What is a Calorie?
*A measure of energy *The amount of energy to raise the temperature of one gram of water one degree Celsius
*Simple sugars *Building block of more complex carbohydrates
1. Glucose (abundant) 2. Fructose 3. Galactose
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Define Disaccharides and list the 3 parts
Two monosaccharides chemically joined
1. Sucrose 2. Lactose 3. Maltose
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What is sucrose and the formula?
glucose + fructose
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What is lactose and the formula?
1. Milk Sugar 2. glucose + galactose
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What is maltose and the formula?
*glucose + glucose *germinating grains
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Define Polysaccharides and give 3 examples.
*complex carbohydrates *hundreds to thousands of sugar units *Glucose is the only monosaccharide *Distinguished by the way in which the glucose units are joined together, their arrangement, and their number
1. Starch 2. Glycogen 3. Fiber (cellulose)
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How is Glucose made and how is it transported?
*During digestion, other carbohydrates are broken down or converted to glucose *Transported by the blood to all the cells in the body *Within cells, respiration breaks down glucose to produce energy necessary to sustain life
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What is Fructose and Galactose?
*both monosaccharides *same chemical make up as glucose, C6H12O6, differing only in the arrangement of the atoms *Converted into glucose and metabolized *High fructose corn syrup (sweeter than sucrose)
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What is Starch?
*Storage form of glucose found in plants *Seeds, some fruits, tubers, and tap roots *Starch in foods can be traced directly to plant origin: starch in bread or pasta from wheat
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Examples of Starches in Human Diet
*Grains (wheat, rice, and corn) *Underground crops (potato, sweet potato, & cassava) *Legumes (beans and peas)
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How and what are starches broken down to?
*broken down to glucose by enzymes in saliva/small intestine *transported by blood to body cells
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Where is Glycogen found and not found?
*liver and skeletal muscles *excess glucose--stored as glycogen *only 1 day's worth of glycogen stored *not in plants
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What is carbohydrate loading?
*eat lots of starchy foods to build glycogen reserves (excess glucose stored as fat)
*contain all 9 essential amino acids *most proteins derived from animals
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What are Incomplete Proteins?
*plant proteins *lack 1 ore more essential amino acid
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What are Complementary Plant Proteins? Give some examples
*combining complementary plant proteins that can supply all E.A.A. *beans and corn
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What essential amino acids are beans low/high in?
*low in methionine *high in tryptophan and lysine *contains complementary proteins
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What essential amino acids is corn low/high in?
*low in lysine and tryptophan *high in methionine *complementary plant proteins
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What is Malnutrition?
quality deficiency in which 1 or more essential nutrients is lacking even though there's enough calories
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What is Undernutrition?
insufficient calories to maintain energy requirements
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What are Fats (lipids)?
*organic molecules *diverse group of compounds *insoluble in water
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List 3 types of fats.
1. Triglyceride 2. Steroid 3. Phospholipid
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What are Tryglycerides and how are they formed?
*95% of lipids in foods - fats and oil *Formed from glycerol and 3 fatty acids
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List 5 characteritics of Fatty Acids
*simplest form of lipids *building blocks for triglycerides and phospholipids *carbon chain w/ hydrogen attached *body can synthesize most fatty acids *number of carbon and hydrogen atoms varies
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What are the 3 fatty acids that must be supplied by the diet?
1. Saturated: all single bonds between carbon atoms 2. Unsaturated: have one or more double bonds
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List 3 characteristics of Saturated Fats.
1. mostly saturated fatty acids 2. solid at room temperature 3. animal fats such as lard, butter, and beef fat
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What are some characteristics of Vegetable Oils.
1. mostly unsaturated fatty acids 2. liquid at room temperature
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What are some vegetable oils with monounsaturated fatty acids
1. olive oil 2. peanut oil 3. canola oil
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What are some vegetable oils with polyunsaturated fatty acids
1. corn oil 2. soybean oil 3. safflower oil
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Give 3 examples of saturated fats in plants
1. coconut oil 2. palm oil 3. cocoa butter
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What is Hydrogenation?
*addition of hydrogen to make an unsaturated oil, a saturated fat *converts a liquid oil into a solid fat - margarine *unsaturated oil has been chemically modified by hydrogenation
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What are the bad effects that diets high in saturated fats lead to?
*colon, breast, and prostate cancers *blood cholesterol levels-linked to cardiovascular disease
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What are the good effects that diets high in unsaturated fats have lead to?
*lower blood cholesterol levels *lower the risk of cardiovascular disease
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What is cholesterol? What is it used for?
*steroid *4 carbon rings *part of lipid component of cell membranes *used in the synthesis of sex hormones and more *Insoluble in the watery medium of blood
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What are trans fats?
*unsaturated fat with transisomer *raise cholesterol levels/cardiovascular disease
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Where is cholesterol made?
synthesized in liver from saturated fatty acids and absorbed by intestinal cells from animal foods
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List examples of food sources that contain cholesterol.