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94 Cards in this Set
- Front
- Back
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What is a gene?
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A segment of DNA that produces a functional product called a polypeptide; unit of hereditary
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What is a polypeptide?
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A linear sequence of amino acids that folds into units that constitute proteins
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What is a trait?
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Characteristics of an organism affected by genes
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What is gene expression?
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The process of using a gene sequence to affect the characteristics of cells and organisms.
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What are the steps of gene expression?
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Transcription and translation
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Define transcription
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The DNA sequence within a gene is copied into a nucleotide sequence of RNA
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What is messenger RNA?
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RNA that contains information for the synthesis of a polypeptide
*not all RNA molecules are translated into polypeptides- only mRNA. |
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What is translation?
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The process where the sequence of nucleotides transcribed in an mRNA is translated into the amino acid sequence of a polypeptide
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What is an allele?
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An alternative form of a specific gene; can be dominant or recessive
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What is a diploid organism?
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A sexually producing species
Contains 2 copies of each chromosome: one from each parent These copies are homologous of each other |
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Define homologous in terms of genes
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2 genes that are derived from the same ancesteral gene. They have similar DNA sequences.
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How many chromosomes do humans have?
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46. They are found in homologous pairs.
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Each homologous pair contains the same type of what?
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Genes
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Which type of human cells are NOT directly involved in sexual reproduction?
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Somatic
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What type of cells are sperm and egg cells?
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Gametes
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How many chromosomes does an egg contain?
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23
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How many chromosomes does a sperm contain?
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23
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Are gametes haploid or diploid?
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Haploid
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How many chromosomes does a gamete having during fertilization? Is it haploid or diploid at this point?
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46
Diploid |
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Which law says that 2 copies of a gene separate from each other during transmission from parent to offspring?
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Mendel's Law of Segregation
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Which law says that 2 different genes will randomly assort their alleles during the formation of haploid cells?
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Mendel's Law of Independent Assortment
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Which law says that in a large population we expect to see ALL genotypes and phenotypes?
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Mendel's Law of Independent Assortment
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What is it called when an offspring receives a combination of alleles that differs from those in the parental generation?
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Genetic recombination
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What is the structure within living cells that contains genetic material?
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Chromosomes
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Where are genes physically located?
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Within chromosomes
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What is the complex between DNA and proteins?
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Chromatin
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What is passed down from mitosis and meiosis?
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Chromosomes
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What is it called when an allele is the most common in a population?
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Wild type allele
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What is a disease allele?
Example? |
An allele with a mistake in the nucleotide sequence.
Example: Huntington's disease |
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Is a somatic cell diploid or haploid?
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Diploid
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What is the term for the physical location of a gene on a chromosome?
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Locus
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How do prokaryotes divide their cells?
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Binary fission
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How do eukaryotes divide their cells?
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Mitosis
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How many chromosomes are found in a human cell?
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46 chromosomes in 23 pairs; one set from each parent
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What is the term for a segment of DNA at the molecular level? AKA the unit of hereditary
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Gene
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What is a polypeptide?
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A linear sequence of amino acids that folds into units that constitute proteins
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Traits are characteristics of an organism affected by what?
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Genes
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What is the definition of an allele?
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An alternative form of a specific gene; can be dominant or recessive
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What are the cells called that are not directly involved in sexual reproduction?
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Somatic cells
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Sperm and egg cells are 2 types of what?
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Gametes
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Are gametes haploid or diploid?
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Haploid
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Which law states that two copies of a gene separate from each other during transmission from parent to offspring?
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Mendel's Law of Segregation
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Which law states that 2 different genes will randomly assort their alleles during the formation of haploid cells?
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Mendel's Law of Independent Assortment
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What is the structure within a living cell that contains the genetic material?
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Chromosome
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What is the chromatin?
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The association between DNA and proteins that is found within chromosomes
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Each chromosome has the same ____ but they may have different _____.
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Gene
Allele |
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What is the term for the 2 copies that remain attached to each other after chromosomal replication?
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Chromatid; sister chromatids
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Are sister chromatids genetically identically?
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Yes
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List the stages of prophase 1 in order from first to last
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Leptotene
Zyogtene Pachytene Diplotene Diakenesis |
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Which stage do replicated chromosomes condense?
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Leptotene
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In which stage do homologous chromosomes recognize each other and begin to align themselves? What is this process called?
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Zygotene; synapsis
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In what stage do bivalent structures form?
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Zygotene
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Homologs are completely aligned in which stage of prophase?
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Pachytene
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How many chromatids are in a bivalent structure?
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4 chromatids in the form of 2 pairs of sister chromatids
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When does synapsis occur?
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Zygotene stage
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What is crossing over and when does it occur?
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It is a physical exchange of chromosome pieces; it happens in the pachytene stage when synapsis is complete
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At what point does the synaptonemal complex disappear?
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Diplotene
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What are the 3 characteristics of the diplotene stage?
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Synaptonemal complex disappears
Bivalent pulls slightly apart Chiasma is visible |
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In what stage does the synaptonemal complex completely disappear?
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Diakinesis
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What stage does the nuclear membrane fragment?
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Prometaphase 1
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What stage do bivalents organize along the metaphase plate?
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Metaphase 1
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Where do the spindle fibers connect to the chromosomes at?
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Kinetochore
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Which anaphase stage do the 2 pairs of sister chromatids separate?
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Anaphase 1
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What are the end products of meiosis 1?
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2 haploid cells
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How many pairs of sister chromatids does each haploid cell have at the end of meiosis 1?
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3 pairs
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Do the cells at the end of meiosis 1 have pairs of homologous chromosomes?
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No
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How many linear strands of chromosome do eukaryotic cells have before replication? After?
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1;2
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What are the end products of meiosis 2?
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4 haploid daughter cells with 3 chromosomes each
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What does meiosis do to the number of chromosomes per cell?
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It halves the number of chromosomes per cell
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Are the daughter cells produced by meiosis genetically identical? Why or why not?
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No- they each contain only one homologous chromosome from each pair.
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Which Mendelian Inheritance pattern obeys Mendel's laws and follow a strict dominant/recessive relationship?
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Simple Mendelian
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Which Mendelian Inheritance pattern is when the heterozygote has a phenotype that is intermediate between either corresponding homozygote?
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Incomplete dominance
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Which Mendelian Inheritance Pattern is when a dominant phenotype is not expressed even though an individual carries a dominant allele?
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Incomplete penetrance
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What is an example of incomplete penetrance?
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An indiviual who carries the polydactyly allele but has a normal number of fingers and toes
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Which Mendelian Inheritance pattern is followed when the heterozygote has a trait that is more beneficial than either homozygote?
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Overdominance
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What is an example of overdominance?
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Sickle cell disease
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Which Mendelian inheritance pattern is followed when the heterozygote expresses both alleles simultaneously?
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Codominance
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What is an example of codominance?
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Human blood type
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Which pattern of Mendelian inheritance is followed when genes are on the X chromosome?
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X-linked
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What type of inheritance is defined by the effect of sex on the phenotype of the individual?
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Sex influenced inheritance
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What type of genes are sex-influenced?
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almost always autosomal
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What is an example of sex-influenced inheritance?
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Pattern baldness in humans
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What is it called when a trait occurs in only one of the 2 sexes?
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Sex-limited
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What is an example of sex limited inheritance?
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Breast development in mammals
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Are genes of sex limited inheritance autosomal or X-linked?
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may be both
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What is a lethal allele?
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An allele that has the potential of causing the death of an organism
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What type of alleles are lethal alleles, most commonly?
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loss-of-function
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What is the term for the degree to which a trait is expressed?
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expressivity
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Genes are typically found in how many alleles?
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3 or more
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What is an example of multiple alleles?
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coat color in rabbits
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What is a gene called that is found on one of the 2 types of sex chromosomes but not both?
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sex-linked gene
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A male mammal is said to be _____ for X-linked genes
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hemizygous
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What is it called when there are multiple effects of a single gene on the phenotype of an organism?
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Pleitrophy
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What is the inheritance pattern called in which the alleles of one gene mask the phenotypic effects of the alleles of a different gene?
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Epistasis
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