˗ˏˋ biology and genetics ´ˎ˗ Flashcards
what is ancient DNA (aDNA)?
molecules that can be found on artifacts such as stone tools and cooking vessels that reveal more about the past.
- typically degraded (i.e., damaged) due to exposure to the elements such as heat, acidity, and humidity.
what is the human genome project?
-began in 1990, completed in 2003.
- international, collaborative research program whose goal was the complete mapping and understanding of all the genes of human beings.
- all our genes together are known as our “genome.”
what are proteins?
chain of amino acids that folds into a three-dimensional structure that allows a cell to function in a variety of ways.
what are lipids?
- fatty acid molecules that serves various purposes in the cell, including energy storage, cell signaling, and structure.
- insoluble in water due to hydrophilic (water-loving) head and a hydrophobic (water-repelling) tail.
what are carbohydrates?
molecules composed of carbon and hydrogen atoms that can be broken down to supply energy.
what is nucleic acid?
a complex structure (like DNA or RNA) that carries genetic information about a living organism.
what is deoxyribonucleic acid (DNA)?
- a molecule that carries the hereditary information passed down from parents to offspring.
- can be described as a “double helix”’ shape.
- includes two chains of nucleotides held together by hydrogen bonds with a sugar phosphate backbone.
what is a DNA sequence?
- the order of nucleotide bases.
- can be short, long, or representative of entire chromosomes or organismal genomes.
what is ribonucleic acid (RNA)?
- single-stranded nucleic acid molecule.
- different types found within cells and they perform a variety of functions, such as cell signaling and involvement in protein synthesis.
who is robert hooke?
in 1665, observed slices of plant cork under microscope; he called what he saw cella, meaning “small rooms” in latin.
what is a prokaryote?
a single-celled organism characterized by lack of nucleus and membrane-enclosed organelles.
what is a eukaryote?
single-celled or multicelled organism characterized by a distinct nucleus, with each organelle surrounded by its own membrane.
what is a microbiome?
the collective genomes of the community of microorganisms that humans have living inside of their body.
what are organelles?
- a structure within a cell that performs specialized tasks that are essential for the cell. - different types each with its own function.
what are archaea?
- a group of primitive prokaryotes that based on their distinct characteristics, form a separate domain from bacteria and eukaryotes.
- distinct evolution aside from bacteria.
what are tissues?
a cluster of cells that are morphologically similar and perform the same task.
what are animal cells?
- have a variety of different tissues.
- have skin, made of keratin, acts in same protective way.
- do not have a thicker membrane.
what are plant cells?
- have a thicker membrane, made of cellulose.
- outermost layer forms a waxy cuticle to protect it.
what is a phospholipid bilayer?
two layers of lipids that form a barrier due to the properties of a hydrophilic (water-loving) head and a hydrophobic (water-repelling) tail.
what is cytoplasm?
the “jelly-like” matrix inside of the cell that contains many organelles and other cellular molecules.
what is a nucleus?
double-membrane cellular organelle that helps protect DNA and also regulates nuclear activities.
what is mitochondrion?
- specialized cellular organelle that is the site for energy production.
- has its own genome (mtDNA).
what is adenosine triphosphate (ATP)?
a high-energy compound produced by mitochondria that powers cellular processes.
what is mitochondrial DNA (mtDNA)?
circular DNA segment found in mitochondria that is inherited maternally.
what is ribosomal RNA (rRNA)?
a ribosome-bound molecule that is used to correctly assemble amino acids into proteins.
what is a nuclear envelope?
a double-layered membrane that encircles the nucleus.
what is a mutation?
- an alteration to the base sequence of DNA; a nucleotide sequence variation from the template DNA strand that can occur during replication.
- mutations can also happen during recombination.
what are molecular geneticists?
biologists that study the structure and function of genes.
what are molecular anthropologists?
individuals who use molecular techniques (primarily genetics) to compare ancient and modern populations and to study living populations of humans and nonhuman primates.
who is rosalind franklin?
- in 1953 discovered DNA structure, major for the scientific community.
- used x-ray crystallography.
- found the unique, double-helix shape.
- credit given to watson, crick and wilkins and received nobel prize in 1962.
what are base pairs?
- chemical bonding between nucleotides, like adenine (A) and thymine (T) or cytosine (C) and guanine (G) in the DNA; or (A) and (U) in RNA.
- approximately three billion DNA base pairs in human cells.
what are nucleotides?
the basic structural component of nucleic acids, which includes DNA (A, T, C, and G) and RNA (A, U, C, and G).
what is the sugar phosphate backbone?
- a biochemical structural component of DNA.
- “backbone” consists of deoxyribose sugars and phosphate molecules.
what is unique about DNA?
- highly organized.
- DNA from one human, stretched out is 2 meters (6.5 feet) long.
what are histones?
protein that DNA wraps around to assist with DNA organization with the nucleus.
what are chromatins?
- DNA wrapped around histone complexes.
- during cell division, chromatin becomes a condensed chromosome.
what are chromosomes?
DNA molecule that is wrapped around protein complexes, including histones.
what is euchromatin?
loosely coiled chromosomes found within the nucleus that is accessible for regulatory processing of DNA.
how many pairs of chromosomes do humans have?
- 23 pairs of chromosomes (total 46) in each cell’s nucleus.
- different organisms have different numbers of chromosomes.
what are centromeres?
- a structural feature that is defined as the “center” of a chromosome and that creates two different arm lengths.
- also refers to the region of attachment for microtubules during mitosis and meiosis.
what are telomeres?
a compound structure located at the ends of chromosomes to help protect the chromosomes from degradation after every round of cell division.
what is DNA replication?
cellular process in which DNA is copied and doubled.
what is the cell cycle?
a cycle the cell undergoes with checkpoints between phases to ensure that DNA replication and cell division occur properly.
what is semi-conservative replication?
DNA replication in which new DNA is replicated from an existing DNA template strand.
what are the steps in DNA replication?
- initiation: the recruitment of protein to separate DNA strands and begin DNA replication.
- elongation: the assembly of new DNA from template strands with the help of DNA polymerases.
- termination: the halt of DNA replication activity that occurs when a DNA sequence ”stop” codon is encountered.
what is helicase?
a protein that breaks the hydrogen bonds that hold double-stranded DNA together.
what is a leading strand?
DNA template strand in which replication proceeds continuously.
what is a lagging strand?
- DNA template strand that is opposite to the leading strand during DNA replication.
- created in several disconnected sections and other enzymes fill in the missing nucleotide gaps between these sections.
what are DNA polymerases?
- enzyme that adds nucleotides to existing nucleic acid strands during DNA replication.
- can be distinguished by their processivity (e.g., DNA replication).
what is mitosis?
the process that somatic cells undergo to divide which results in two diploid daughter cells.
what are somatic cells?
diploid cells that comprise body tissues and undergo mitosis for maintenance and repair of tissues.
what does it mean to be diploid?
refers to an organism or cell with two sets of chromosomes.
what are homologous chromosomes?
a matching pair of chromosomes wherein one chromosome is maternally inherited and the other is paternally inherited.
what are sister chromatids?
- during DNA replication, they are produced on the chromosome.
- in cell division, they are pulled apart so that two cells can be formed.
- in meiosis, they are also the sites of genetic recombination.
what are gametes?
haploid cells referred to as an egg and sperm that will fuse together during sexual reproduction to form a diploid organism.
what is meiosis?
the process that gametes undergo to divide which results in four haploid daughter cells.
what is genetic recombination?
a cellular process that occurs during meiosis I in which homologous chromosomes pair up and sister chromatids on different chromosomes physically swap genetic information.
what are chromosomal disorders?
- they occur in mitosis or meiosis.
- the 23rd pair of chromosomes in humans are what indicates biological sex.
what is an aneuploid?
a cell with an unexpected amount of chromosomes. The loss or gain of chromosomes can occur during mitotic or meiotic division.
what is karyotyping?
the microscopic procedure where the number of chromosomes in a cell is determined.
what is down syndrome?
has three copies of the 21st chromosome.
what is interphase?
preparatory period of the cell cycle when increased metabolic demand allows for DNA replication and doubling of the cell prior to cell division.
what is klinefelter syndrome?
- xxy.
- a genetic condition in which a male is born with an extra copy of the X chromosome.
- lower testosterone and body hair.
what is triple X syndrome; trisomy X?
- xxx.
- a genetic condition in which a female is born with an extra copy of the X chromosome.
- many women experience no side effects; most common is added height.
what is turner syndrome?
- xo.
- a genetic condition in which a female is missing part, or all, of an X chromosome.
- symptoms include short stature, delayed puberty, infertility, heart defects, and certain learning disabilities.
what is protein synthesis?
a multi-step process by which amino acids are strung together by RNA machinery read from a DNA template.
what are the steps of protein synthesis?
- transcription: the process by which DNA nucleotides (within a gene) are copied, which results in a messenger RNA molecule.
- translation: the process by which messenger RNA codons are read and amino acids are “chained together” to form proteins.
how many types of amino acids are there?
20.
what is messenger RNA (mRNA)?
- RNA molecule that is transcribed from DNA.
- its tri-nucleotide codons are “read” by a ribosome to build a protein.
what is splicing?
the process by which mature mRNAs are produced. Introns are removed (spliced and exons are joined together.
what is a gene?
segment of DNA that contains protein-coding information and various regulatory (e.g.; promoter) and noncoding (e.g. introns) regions.
what is RNA polymerase?
an enzyme that catalyzes the process of making RNA from a DNA template.
what are introns?
segment of DNA that does not code for proteins.
what are exons?
protein-coding segment of a gene.
what is a ribosome?
-a n organelle in the cell found in the cytoplasm or endoplasmic reticulum.
- it is responsible for reading mRNA and protein assemblage.
what are codons?
a sequence that comprises three DNA nucleotides that together code for a protein.
what is transfer RNA (tRNA)?
- RNA molecule involved in translation. - transports amino acids from the cell’s cytoplasm to a ribosome.
what is mendelian genetics?
a classification given to phenotypic traits that are controlled by a single gene.
what is a genotype?
the combination of two alleles that code for or are associated with the same gene.
what are alleles?
a non-identical DNA sequence found in the same gene location on a homologous chromosome, or gene copy, that codes for the same trait but produces a different phenotype.
what is a punnett square?
- square diagram that is used to predict the genotypes of a particular cross or breeding experiment.
- named after reginald punnett, one of the first english genetics.
what are heterozygous genotypes?
genotypes that consists of two different alleles.
what are homozygous genotypes?
genotypes that consists of two identical alleles.
what are cell surface antigens?
a protein that is found on a red blood cell’s surface.
what are antibodies?
immune-related proteins that can detect and bind to foreign substances in the blood such as pathogens.
what are codominance?
the effects of both alleles in a genotype can be seen in the phenotype.
what is a pedigree?
a diagram of family relationships that indicates which members may have or carry certain genetic and/or phenotypic traits.
what is a carrier?
an individual who has a heterozygous genotype that is typically associated with a disease.
what is autosomal?
refers to a pattern of inheritance where an allele is located on an autosome.
what is X-linked?
refers to a pattern of inheritance where the allele is located on the X or Y chromosome.
what is incomplete dominance?
heterozygous genotype that produces a phenotype that is a blend of both alleles.
what is a polygenic trait?
- a phenotype that is controlled by two or more genes (hair and eye color).
- human hair color is tied to melanin
- oculocutaneous albinism occurs when there are two non-functioning copies of the gene TYR, the hair skin and eyes have little, to no melanin or coloring.
what are complex diseases?
a category of diseases that are polygenic and are also influenced by environment and lifestyle factors
(cardiovascular disease, schizophrenia, alzheimer’s).
- can run in families, but are currently not fully understood how or when they are passed through generations.
what is pathogenic?
a genetic mutation (i.e., allele) that has a harmful phenotypic disease-causing effect.
what is penetrance?
- the proportion of how often the possession of an allele results in an expected phenotype.
- some alleles are more penetrant than others.
what is a genome?
all the genetic information of an organism.
what is genotyping?
- a molecular procedure that is performed to test for the presence of certain alleles or to discover new ones
- how we learned that humans and chimpanzees (as well as bonobos) share a lot of DNA.
what is sequencing?
a molecular laboratory procedure that produces the order of nucleotide bases (i.e., sequences).
what is epigenetics?
- changes in gene expression that do not result in a change of the underlying DNA sequence.
- typically involve DNA methylation and histone modifications.
- changes are reversible and can also be inherited by the next generation.
what is DNA methylation?
methyl groups bind DNA, which modifies the transcriptional activity of a gene by turning it “on” or “off”.
what is an epigenetic profile?
- the methylation pattern throughout a genome – that is, which genes (and other genomic sites) are methylated and unmethylated.
- identical twins have their own epigenetic profiles, which become more different as they age.
what is newborn screening?
- has been available in the US for over 50 years.
-one of the first tests available was for a phenylketonuria (PICU/PKU) diagnosis. - phenylketonuria(PICU/PKU) is birth defect that causes an amino acid called phenylalanine to build up in the body.
- untreated phenylketonuria can lead to brain damage, intellectual disabilities, behavioral symptoms, or seizures.
- it is treatable through dietary restrictions of protein.
what is polymerase chain reaction (PCR)?
-molecular biology procedure that can make copies of genomic DNA segments.
- a small amount of DNA is used as a starting template and is then used to make millions of copies.
what is sanger sequencing?
- a process that involves the usage of fluorescently labeled nucleotides to visualize DNA (PCR fragments) at the nucleotide level.
- several different types of alleles and genetic changes can be detected in DNA by using this analysis.
what is direct-to-consumer (DTC) genetic disease testing?
- done without the guidance of medical professionals.
- should be used as a starting point for further testing of genetic diseases.
- no further help or information and can be difficult to interpret by nonmedical professionals.
- starting point for genetic carriers.
- can help guide lifestyle moving forward.
how does direct-to-consumer (DTC) ancestry testing work?
- customers are genotyped.
- alleles assigned to different ethnic groups.
what are the benefits and disadvantages of direct-to-consumer (DTC) ancestry testing?
- can help people who have lost their cultural ancestry.
- some sites partnered with law enforcement.
- results could change as the reference population grows.
- does not automatically provide cultural ties to those groups.
