Genetic Genealogy W03 Flashcards
Alleles
a particular gene code for an individual human trait, eye color, hair color, etc
Cells
smallest living organism.
Organelles
“little organ” Special parts of the cell that have unique jobs to fulfill.
Chromatin
the tangled spread out form of DNA found inside the nuclear membrane, this condenses into chromosomes for division
Centrioles
involved in cell division
Cellular Respiration
process in which the mitochondrion produces ATP molecules that provide all the energy for the cells activities
Chromosome
a highly organized double helix of two DNA molecules
Crossing over (recombination)
the switching of alleles on homologous chromosomes during meiosis. This creates the unique genome for every person (part mother, part father)
Cytoplasm
jelly like substance or fluid inside the cell
Cytoskeleton
creates the shape of the cell using microfilaments made of proteins and microtubules
Diploid
a cell containing all 23 pairs of the chromosomes
DNA (Deoxyribonucleic Acid)
a double-stranded molecule comprising two entwined strings of millions of different nucleotides
Eukaryotic cells
Plant and animal cells with a nucleus and membrane-enclosed organelles
Flagella
tail like part that can help a cell move or propel itself. Sperm cells are examples of this
Gametes
haploid cells (sperm and egg)
Gene
a region of DNA along a chromosome that encodes for a function such as a protein
Genome
an organism’s complete set of DNA
Golgi apparatus (Golgi body)
customizes the proteins into forms the cell can use. The proteins are folded into usable shapes and/or other materials added on to them like lipids and carbohydrates
Haploid
containing half the normal number of chromosomes. Gametes (sperm and eggs) are haploid cells.
Homologous Chromosomes
are two chromosomes in a pair of autosomes that contain corresponding sequences of DNA from separate parents. They are similar but not identical copies of each other.
Karyogram
an image of all of the chromosomes of the human cell arranged in pairs in a numbered sequence from longest to shortest
Karyotype
all of the chromosomes of the human cell arranged in pairs in a numbered sequence from longest to shortest
Lysosome
a cell organelle that breaks down damaged or worn out cell parts
Meiosis
a process involving two successive divisions of a cell, resulting in four daughter cells. Unlike what occurs in mitosis, the daughter cells produced in meiosis are haploid and not identical to each other
Mitochondrion
the power house of the cell which provides energy to the cell
Mitosis
a process in cells where one cell divides into two new cells, both identical to the original
Nitrogenous Bases
are Adenine, Thymine, Cytosine, and Guanine. They pair as C with G and A with T.
Nucleolus
a structure where Ribosomes are made
a Nucleotide
the building blocks of who we are and they have three components—a sugar molecule, a phosphate group, and a nitrogenous base.
Nucleotides
The four different building blocks of a DNA molecule: adenine, cytosine, guanine, and thymine. DNA is composed of millions of units called nucleotides.
Nucleus
an organelle that is the control center of the cell and contains DNA
Prokaryotic cells
Unicellular organisms without a nucleus or membrane-enclosed organelles
Ribosomes
they synthesize or make proteins
Rough Endoplasmic Reticulum (rER)
has ribosomes attached
Smooth Endoplasmic Reticulum (sER)
has no ribosomes attached
SNPs (Single Nucleotide Polymorphism)
Nucleotides that commonly differ among the human population
Vacuoles
sack like structures that store different materials
Vesicle
formed by ribosomes to carry them to the Golgi apparatus
All cells have 3 things in common. What are they?
They all have a cell membrane, cytoplasm, and DNA
Independent Assortment
a Process by which each chromosome is shuffled into a daughter cell during meiosis. Chromosomes do not remain associated with their homologues.
Sister Chromatid
A double helix of DNA, tightly coiled and compacted into a rod-like form. Two identical chromatids are sister chromatids.
Nuclear Membrane
Separates the nucleus from the cytoplasm of the cell. It is similar to the cell membrane in that it is selectively permeable.
Phosphate Group
A chemical group consisting of one phosphate atom and three oxygen atoms.
Nitrogenous Base
One of the molecular components of a nucleotide; a class of ringed molecules with carbon, oxygen, hydrogen, and nitrogen.
Mitotic Spindle
Array of microtubules that forms during mitosis and physically separates duplicated chromosomes.
Contractile Ring
Temporary structure made of actin filaments that divides a cell during mitosis or meiosis.
Huntington Gene
The section of DNA that codes for the huntingtin protein. (The scientific literature on HD refers to the gene as both the Huntington gene and the huntingtin gene. For the purposes of this website, we will refer to the gene as the Huntington gene or, when it is in the altered form that results in HD, the HD allele.)
Clone
A cell, group of cells, or organism that is descended from and genetically identical to a single common ancestor.
Trait
A physical characteristic brought about by the expression of a gene or many genes. Examples of traits are height, eye color, and the ability to roll your tongue. Variations in these characteristics are dependent upon the particular alleles an individual has for the genes determining the trait.
Mass
The amount of matter in an object; often used interchangeably with weight. (Weight is actually the force with which an object is attracted toward the center of the earth.)
Base
In genetics, a DNA letter (A,C,G or T). Also known as a nucleotide.
Sugar
One of the molecular components of a nucleotide; sugars are a class of molecules made up of carbon, oxygen, and hydrogen arranged in a ringed structure.
Basic
Adjective used to describe a substance or solution that contains a relatively low amount of positive hydrogen ions.
Zygote
The first cell created after an egg is fertilized by a sperm.
Thymine
One of the four building blocks of DNA, often abbreviated as the letter “T”; pairs with the base adenine.
Guanine
One of the four nitrogenous bases found in DNA; pairs with the base cytosine; often abbreviated as the letter ‘G’; see Figure B-3.
Bivalent
A physical connection between homologous chromosomes that forms duringmeiosis. Crossing over takes place when the chromosomes are in this orientation.
E. coli
A small, simple bacteria used in many biology laboratories.
Cystonine
One of the four nitrogenous bases found in DNA; pairs with the base guanine; often abbreviated as the letter ‘C’
Adenine
One of the four nitrogenous bases found in DNA; pairs with the base thymine. Often abbreviated as the letter “A”. Also found in RNA, where it pairs with the base uracil.
Hereditary
The passing of traits from one generation to the next.
Bacteria
A small, single-celled living organism that has DNA and can replicate its own DNA without the help of a host cell. Some bacteria are helpful to humans, such as those that live in our stomach and help with digestion, while some are harmful, releasing toxins or poisonous waste products.
Phosphate
One of the molecular components of a nucleotide; a small molecule made up of phosphorus and oxygen.
Molecule
The smallest unit of matter of a substance that retains all the physical and chemical properties of that substance, consisting of a single atom or a group of atoms bonded together. Example: A single water molecule (H2O) consists of just one single oxygen atom bonded to just two hydrogen atoms. There are billions of billions of water molecules in a single droplet of water. Molecules are too small to be seen without the assistance of powerful microscopes.
Essential
A substance that cannot be produced from the body, and therefore must be obtained from the diet.
Expansion
A mutation involving the increase from one generation to the next (parent to child) in the number of copies of a certain codon. In Huntington’s disease expansions, the codon is CAG.
Germ Cell
A kind of cell that gives rise to the reproductive cells. See also germ line.
HD allele
A version of the Huntington gene that contains a higher than normal number of repeats. Individuals with the HD allele will develop Huntington’s disease (Note that there are many different alleles that can cause HD, but for simplicity, this site refers to any allele that causes HD as the HD allele.) This allele may be called the mutant Huntington allele in other places.
Interphase
Stage of the cell cycle that occurs between divisions. DNA is replicated during this phase.
Replication
The process by which DNA copies itself before cell division. Unless mutation occurs, the new copy of DNA is identical to the original DNA. (Verb form:replicate.)
Gene Locus
Place on a chromosome where a gene is located. A particular gene is located at the same place on the same chromosome in everyone. Plural: loci.
centrosomes
The major microtubule organizing centers of an animal cell.
double helix
The form in which DNA is most often found in living cells; consists of two complementary single strands of DNA, spiraling around one another.
recombination
An event that occurs during meiosis involving the transfer of segments of DNA from one homologous chromosome to the other.
complementary
A property of DNA whereby each nitrogenous base pairs with another particular base (A with T and G with C); two complementary single strands have nucleotide sequences that enable their bases to pair up.
nondisjunction
An event that can occur during meiosis in which chromosomes fail to separate properly, resulting in daughter cells with too many or too few chromosomes.
crossing over
An event that occurs during meiosis. During crossing over, alleles on homologous chromosomes can switch places. This switching of alleles increases the number of possible combinations of alleles, and hence increases the variability of a genome. In other words, crossing over contributes to the ability of two parents to produce offspring that are all very different. Also referred to as ‘recombination.’
daughter cells
The cells that result from the reproductive division of one cell during mitosis or meiosis.
cell division
A brief time interval during which a cell reproduces by dividing into two; during this period, the DNA in chromosomes becomes highly condensed, making the chromosomes easily visible.
