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92 Cards in this Set
- Front
- Back
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Define Gene
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Unit of heritable information; section of DNA that encodes one structural or functional component of an organism
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Define Allele
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Two or more molecular forms of a gene that encode slightly different versions of the same trait. Arise by mutation. Example : Gene is the ice cream, Alleles are the flavors of ice cream
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What is the difference between a gene and an allele?
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An allele is a mutation of a gene. Example : The original gene for flower color calls for purple, the mutated form (allele) calls for white.
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What are the monomers of DNA and RNA?
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Nucleotides
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What are the three parts of a nucleotide?
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1. Five carbon sugar
2. Phosphate group 3. Nitrogen containing bases |
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What is complementary base pairing? Why is it important?
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The two strands of DNA match up; they are said to be complementary to each other. Although the molecular bonding pattern (A to T, and G to C) is the same in every molecule of DNA, the actual sequence of bases differs for every species. This molecular variation is the foundation for the diversity of life.
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Which nitrogen bases are complementary with one another?
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-Adenine to Thymine
-Cytosine to Guanine |
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Describe the structure of DNA.
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-Deoxyribose sugar (five-carbon sugar)
-Phosphate group -Nitrogen Base |
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What is the function of DNA?
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It’s sequence encodes primary hereditary information for all living organisms and many viruses.
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Describe how DNA replicates itself.
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DNA is replicated prior to cell division. Enzymes unwind its two strands. Each strand remains intact throughout the process-it is conserved-and enzymes assemble a new, complementary strand on each one.
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Why do we call the replication of DNA semi-conservative?
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Because the parent DNA is saved (conserved) during the replication process, half of every double-stranded DNA molecule is “old” and half is “new”. The process is called semi-conservative replication.
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What are the three ways in which RNA differs from DNA?
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-RNA is Single stranded, ribose sugar, uracil.
-DNA is double stranded, deoxyribose sugar, thymine. |
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What are the three types of RNA?
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Messenger RNA (mRNA)
Ribosomal RNA (rRNA) Transfer RNA (tRNA) |
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What is the function of rRNA?
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-Provide a mechanism for decoding mRNA into amino acids.
-Interact with tRNA during translation. |
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What is the function of tRNA?
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-Delivers amino acids to ribosomes.
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What is the function of mRNA?
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Carries protein building instructions.
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Where are proteins formed in the cell?
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Cytoplasm
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What is transcription?
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Process by which an mRNA is assembled from nucleotides using a gene region in DNA as a template.
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Where does transcription occur in the cell?
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Nucleus
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What is the end product of transcription?
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mRNA
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What is translation?
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Second stage of protein synthesis. At ribosomes, information encoded in an mRNA transcript guides the synthesis of a new polypeptide chain from amino acids.
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What is the end product of translation?
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Protein (polypeptide chain)
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What is a codon and where would you find it?
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Base triplets found in mRNA
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What is an anticodon and where would you find it?
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A base triplet that is complementary to an mRNA codon. Found on tRNA.
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Explain the how the genetic code chart works.
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The left vertical column lists choices for the first of three bases in an mRNA codon. The top horizontal row lists choices for the second codon. The right vertical column lists choices for the third.
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What is the "Central Dogma"?
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DNA ---transcription--mRNA ---translation--Protein
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What are the monomers of a protein?
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Amino Acids
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Why are proteins important in the cell?
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-They make up muscles
-They are enzymes |
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What kind of bond forms between the nitrogen bases in DNA?
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Hydrogen
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Why do scientists now think that RNA arose before DNA or protein?
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RNA can replicate itself, store information, act as a catalyst and organize amino acids.
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What is a chromosome?
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-Gene carrying structure of a cell.
-1 or 2 molecules of DNA wrapped around spools of protein |
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What is a chromatid?
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One of two identical strands of DNA making up a chromosome that are joined at there centromeres.
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What is a sister chromatid?
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A chromosome and it's duplicate.
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What is the difference between an unreplicated chromosome and a replicated one?
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An un-replicated chromosome has one chromatid a replicated chromosome has two chromatids.
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What is a karyotype?
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Preparation of an individual's diploid complement of chromosomes.
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How many sets of chromosomes does a haploid organism have? a diploid organism?
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-Haploid has one set
-Diploid has two sets |
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What are the haploid and diploid numbers in humans?
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-Haploid is 23
-Diploid is 46 |
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How is an autosome different from a sex chromosome?
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-Autosomes are similar is size and do not determine sex.
-Sex chromosomes are not similar in size and do determine sex. |
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How many autosomes does a person receive from their father?
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22
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How many autosomes are present in a diploid human cell?
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44
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How many sex chromosomes are present in a diploid human cell?
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2
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Define a homologous chromosome.
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One of a pair of chromosomes in a diploid cell; except for no identical sex chromosomes, a pair has the same size, shape, and gene sequence.
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Why are the X and y chromosomes not homologous?
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They are not members of a pair, different size, shape, and gene sequence.
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What is a somatic cell?
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A body cell
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In what cells does mitosis occur?
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Somatic cells
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What is the function of mitosis?
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To produce more cells
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Why is interphase not part of mitosis?
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Interphase is the stage in which a cell prepares for mitosis. It is not technically part of mitosis but rather encompases stages G1, S and G2 of the cell cycle.
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What are the two things that are different between plant and animal mitosis?
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Animal cells have centrioles and cytokinesis creates a cleavage furrow. Plant cells do not have centrioles and cytokinesis forms a cell plate.
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In what phase of mitosis do the sister chromatids separate?
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Anaphase
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What is the difference between the nucleus and the nucleolus?
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The nucleolus is part of the nucleus.
The nucleus contains the DNA, the nucleolus produces ribosomes which move out of the nucleus to the ER and are critical in protein synthesis. |
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Explain how cytokinesis in animal cells is different from cytokinesis in plant cells.
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Animal cells have a cleavage furrow and plant cells have a cell plate.
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In what cells of the body does meiosis occur?
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Reproductive cells
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How is the function of meiosis different from that of mitosis?
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-Meiosis is the basis of gamete and spore formation in sexual reproduction.
-Mitosis is the basis of body growth, cell replacements, tissue repair and asexual reproduction in eukaryotes. |
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What is synapsis?
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The pairing of two homologous chromosomes that occurs during meiosis.
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Why do homologous chromosomes synapse?
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They come together so they can crossover.
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In what stage of meiosis do homologous chromosomes synapse?
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Prophase 1
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Describe crossing over.
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Non-sister chromatids break at the same places along their length and exchange corresponding segments.
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What is the function of crossing over?
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It breaks up old combinations of alleles and puts new ones together in pairs of homologous chromosomes which leads to different combinations of maternal and paternal traits in each new generation.
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Do sister chromatids undergo crossing over?
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No
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What phase of meiosis do the sister chromatids separate?
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Anaphase 2
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How many chromosomes are on a spindle fiber in Metaphase 1? Metaphase 2?
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Metaphase 1 = Two
Metaphase 2 = One |
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If a cell had 18 chromosomes before meiosis, how many chromosomes would there be after meiosis?
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9
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List four ways in which meiosis differs from mitosis
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Mitosis - In somatic cells, one division takes place, two daughter cells, no crossing over.
Meiosis - In reproductive cells, two divisions take place, four daughter cells, crossing over. |
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What is a gamete?
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Egg/Sperm
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How is a gamete different from a somatic cell?
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Gamete is a reproductive cell, a somatic cell is a normal body cell.
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How many copies of an allele does each gamete receive?
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One
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What is non-disjunction?
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Failure of one or more homologous chromosomes to separate during meiosis.
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What is translocation?
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Transfer of one part of a chromosome to a non-homologous chromosome OR transfer of an entire chromosome to another non-homologous chromosome.
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Who is Gregor Mendel? Why is he famous?
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Monk who attended the University of Vienna and studied math and science. He found indirect but observable evidence of how parents transmit genes to offspring.
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What are Mendel's two laws?
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1. Law of Segregation = Each gamete has one copy of an allele, gametes combine randomly to form offspring.
2. Independent Assortment = Genes on different chromosomes inherited independently of one another. |
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How is the homozygous condition different from the heterozygous condition?
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-Homozygous Condition is when two alleles on homologous chromosomes are identical.
-Heterozygous Condition is when two alleles are not identical. |
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What does it mean to say that an allele is dominant?
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When its effect on a trait masks that of any recessive allele paired with it.
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What does it mean to say that an allele is recessive?
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When its effect on a trait is masked by a dominant allele paired with it.
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How would you determine which allele is dominant and which is recessive?
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Punnett Square
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What is a phenotype?
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Physical make-up, the physical expression of a gene.
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What is a genotype?
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Genetic make-up
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How is phenotype different from genotype?
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-Genotype refers to the particular alleles that and individual carries.
-Phenotype refers to the physical expression of the genes. |
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How many genes are involved in a monohybrid cross?
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One
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How is sex linked inheritance different from autosomal inheritance?
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Sex linked is only carried on the sex chromosomes.
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Which chromosome contains the gene for hemophilia and the gene for color-blindness?
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Chromosome 11
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Why is the ABO blood group an example of multiple alleles and an example of codominance?
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Multiple alleles is one gene with three alleles, and codominance is when two alleles are expressed. The ABO blood group has three alleles in which in some cases 2 are expressed.
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How is an antigen different from an antibody?
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-Antigen is a molecule on the surface of RBC's that aids your body in self recognition.
-Antibody is a protein molecule produced by your body to bind foreign antigen. WBC's then come along and devour antigens. |
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What is polygenic inheritance?
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-More than one gene contributes to trait in an additive fashion.
-Continuous variation. -Skin color, eye color, Rh factor. |
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Why are eye color and skin color examples of polygenic inheritance?
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Multiple genes contribute which can result in a variety of skin or eye colors.
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What is the theory of evolution?
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All living things arose by descent from a common ancestor as a result of genetic modification taking place in species that lived before them.
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What are the 5 mechanisms of evolution?
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1. Natural Selection
2. Mutation 3. Gene Flow 4. Genetic Drift 5. Non-Random Mating |
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Natural Selection
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-Member of a species vary in form and behavior.
-Some of the variation is inherited. -Some inherited traits may improve chances of survival and reproduction. -Organism with these traits leave more offspring than others therefore we have differential reproductive success. |
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Mutation
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-Change in DNA
-Changes an allele to a new one -Raw material for natural selection |
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Gene Flow
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Migration removes alleles from one group and adds them to another group. Example : Prairie Dogs
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Genetic Drift
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Unpredictable change in allele frequency due to small population size
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Non-Random Mating
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Tendency of individuals of one phenotype to mate with individuals of another specific phenotype.
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What is the "red queen effect"?
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-You must run faster just to stay in the same place.
-Environment changes overtime. -Populations adapt, but always lag behind changes in environment. |
