Term
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Definition
-scientific study of heredity
-genes control what cells look like and do
-understanding how genes work is essential to understanding life |
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Term
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Definition
-a genome is the complete set of genes carried by an organism
-genomics is a field of study that focuses on the organization, function, and evolution of genomes |
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Term
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Definition
-a string of nucleotides in a DNA molecule
-basic structural and functional unit of genetics
-when it is turned on, it is used to make a protein (some genes code for functional RNA molecules, which do not code for proteins) |
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Term
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Definition
| sequence of nucleotides that encodes the information for amino acids in a polypeptide chain |
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Term
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Definition
| threadlike structures in the nucleus that carry genetic information |
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Term
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Definition
-chromosomes other than the sex chromosomes
-human chromosomes 1-22 |
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Term
| What are sex chromosomes? |
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Definition
-human X and Y chromosomes
-Male= XY
-Female= XX |
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Term
| What is a chromosomal disorder? |
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Definition
-a defect due to an excess or a deficiency of the genes contained in whole chromosomes or chromosome segments
-Ex: trisomy 21 causes Down Syndrome
-about 7 per 1000 live born infants
-about half of all spontaneous first-trimester abortions |
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Term
| What are single gene defects? |
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Definition
-caused by mutations in individual genes
-the mutant may be on an autosome, a sex chromosome, or in the mitochondrial genome
-RARE: 1 in 1000 is the highest frequency |
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Term
| What are multi factorial inheritance genetic disorders? |
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Definition
-responsible for the majority of diseases
-include prenatal development disorders, as well as many common disorders in adult life
-disease is the result of multiple different genes acting together, often in concert with environmental factors
-incidence of multifactorial diseases is about 5% in the pediatric population and about 60% in the entire pop. |
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Term
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Definition
-The basic building block of DNA and RNA
-each contains a phosphate group, a sugar, and a nitrogen-containing base |
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Term
| What is semiconservative replication? |
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Definition
| -a model of DNA replication that provides each daughter molecule with one old strand and one newly synthesized strand |
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Term
| Each human chromosome contains a _____ DNA molecule |
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Definition
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Term
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Definition
| The complex of DNA and proteins that makes up a chromosome |
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Term
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Definition
| DNA-binding proteins that help compact and fold DNA into chromosomes |
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Term
| Mitochondrial genes are inherited exclusively ___________ |
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Definition
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Term
| Of the 3 billion base pairs of DNA in the human genome, less than 1.5% ________/____/_________, and about 5% is thought to contain _________/________ |
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Definition
-encodes for proteins
-regulatory elements |
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Term
| Only ______ of the genome consists of unique or single-copy DNA sequence; the remainder consists of several classes of repetitive DNA sequence |
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Definition
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Term
| Most of the estimated 20,000 genes exist as _______/______ |
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Definition
unique DNA
(the repetitive DNA sequence contributes to maintaining chromosome structure and are an important source of variation between individuals) |
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Term
| What are single-copy DNA sequences? |
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Definition
-makes up about half of the genome, but the function of most remains unknown
-most is found in short stretches (several kb pairs or less) interspersed with members of various repetitive DNA families |
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Term
| What are repetitive DNA sequences? |
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Definition
-several different categories of repeats are recognized based on clustering or being interspersed throughout the genome
-clustered repeats make up about 15% of the genome and exist in tandem arrays that vary in length (satellite DNAs) |
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Term
| How can repetitive DNA cause disease? (3) |
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Definition
| -by integrating into genes, by aberrant recombination between different elements, and by segmental duplications and rearrangements |
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Term
| What does mitosis begin and end with? |
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Definition
| -it starts with a single diploid cell and ends with two genetically identical diploid cells |
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Term
| What does meiosis begin and end with? |
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Definition
| -it starts with a single diploid cell and ends with four genetically unique haploid cells |
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Term
| What is the cell cycle and its three phases? |
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Definition
-the sequence of events by which a cell duplicates its contents and divides into two genetically identical daughter cells
*interphase
*mitosis
*cytokinesis |
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Term
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Definition
-the period of time between mitotic divisions
-the phase when chromosomes are duplicated |
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Term
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Definition
| -duplicated chromosomes separate into two nuclei, each with the same genetic information as the parent cell's |
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Term
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Definition
the cytoplasmic division phase of cell division
-cleavage furrow divides the cell in two
-organelles are distributed to two daughter cells |
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Term
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Definition
-one strand of a duplicated chromosome
-joined by a centromere to its sister chromatid |
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Term
| What are sister chromatids? |
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Definition
-two chromatids joined by a common centromere
-each carries identical genetic information |
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Term
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Definition
-the region of a chromosome to which spindle fibers attach during cell division
-region of a chromosome that connects sister chromatids
-centromere location gives a chromosome its characteristic shape |
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Term
| What are the 4 stages of mitosis? |
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Definition
1-Prophase: chromosome become visible and contain sister chromatids joined at the centromere, spindle fibers attach to centromeres
2-metaphase: stage in mitosis when chromosomes move and become arranged at the middle of the cell
3-anaphase: stage in mitosis in which the centromeres split and daughter chromosomes begin to separate
4-telophase: last stage of mitosis, chromosomes of the daughter cells decondense and nucleus reforms |
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Term
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Definition
| -a complete set of chromosomes from a cell that has been photographed during metaphase of mitosis and arranged in a standard sequence |
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Term
| What is the difference between diploid (2n) and haploid (n) |
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Definition
-diploid: each chromosome is represented twice as a member of a homologous pair
-haploid: each chromosome is represented once, in an unpaired condition |
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Term
| What are homologous chromosomes? |
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Definition
-maternal and paternal, with identical gene loci
-chromosomes that physically pair during meiosis |
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Term
| What is random assortment? |
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Definition
-gametes receive random combination of maternal and paternal chromosomes
-result of meiosis I |
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Term
| What are the two ways that meiosis produces new combinations of parental genes in the eggs and sperm? |
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Definition
-random assortment of maternal and paternal chromosomes in metaphase 1
-crossing over (recombination): the exchange of chromosome segments between homologues |
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Term
| What is the essential step in the formation of gametes? |
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Definition
| -reduction of chromosome number from diploid to haploid |
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Term
| In males, meiosis produces _________ and spermiogenesis produces _________. Collectively this is called _________ |
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Definition
| spermatids, spermatozoa, spermatogenesis |
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Term
| What is the total time needed to produce a mature sperm? a mature egg-zygote? |
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Definition
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Term
| Transfer of information from the linear sequence of nucleotides in DNA to the linear sequence of amino acids in a protein occurs in two steps: ________ and ________ |
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Definition
| transcription and translation |
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Term
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Definition
| DNA to mRNA- transfer of genetic info from the base sequence of DNA to the base sequence of RNA, mediated by RNA synthesis |
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Term
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Definition
| mRNA to protein: conversion of information encoded in the nucleotide sequence of an mRNA molecule into the linear sequence of amino acids in a protein |
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Term
| What is the promoter region on a eukaryotic gene? |
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Definition
| RNA polymerase binds here and initiates transcription |
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Term
| What is the exon portion of a eukaryotic gene? |
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Definition
| DNA sequences that are transcribed into mRNA and translated into amino acid sequence of a protein |
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Term
| What is the intron portion of a eukaryotic gene? |
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Definition
| DNA sequences that are transcribed, but are spliced out of the pre-mRNA and not included in the mRNA |
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Term
| What is the terminator region on a eukaryotic gene? |
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Definition
| DNA sequence that signals the end of transcription |
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Term
| What is the cap of a mRNA molecule? |
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Definition
| a modified base (guanine nucleotide) attached to the 5' end of eukaryotic mRNA molecules during RNA processing |
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Term
| What is the poly-A tail of a mRNA molecule? |
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Definition
| a string of 30-100 adenine nucleotides added to the 3' end of mRNA molecules during RNA processing |
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Term
| What is splicing of the pre-mRNA molecule? |
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Definition
| the introns are spliced out to produce mature mRNA |
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Term
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Definition
| a single-stranded complementary copy of the DNA sequence in a gene |
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Term
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Definition
triplets of nucleotides in mRNA that encode the information for a specific amino acid in a protein
-information transferred from DNA to mRNA is encoded in codons |
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Term
| Of the 64 possible codons, how many code for the 20 amino acids found in proteins? what do the others do? |
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Definition
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Term
| What are three major differences between DNA and RNA? |
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Definition
-DNA sugar is deoxyribose, RNA is ribose
-DNA has thymine, RNA has uracil
-DNA is a double strand, RNA is a single strand |
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Term
| What is the start codon for every single human protein? |
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Definition
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Term
| The codon in a mRNA molecule attaches to the _______ in tRNA |
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Definition
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Term
| What are the three main parts of an amino acid? |
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Definition
-amino group: (NH2) found in all amino acids at one end of a polypeptide chain
-carboxyl group: (COOH) same as above
-R group: each amino acid has a different side chain called an R group |
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Term
| The covalent chemical link between the carboxyl group of one amino acid and the amino group of another amino acid is a __________ bond |
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Definition
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Term
| What is the N-terminus in a polypeptide? |
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Definition
| the end of a polypeptide or protein that has a free amino group (the first amino acid in the polypeptide) |
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Term
| What is the C-terminus of a polypeptide? |
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Definition
| -the end of a polypeptide or protein that has a free carboxyl group (the last amino acid in the polypeptide) |
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