Final Flashcards
Chromosome
- single DNA molecule with proteins attached
- linear in eukaryotes and circular in prokaryotes
- term is also used for 2 identical DNA molecules
- attached at centromeres
- 46 in humans-contain over 25,000 genes
- 3% of the DNA is contained in genes-97% non-coding(no genes)
- Genes are spaced (cut with restriction enzymes)
Non-coding regions
-can act as a “sponge” and causes it to react with the problem and don’t have as many mutations.
Contain:
1) regulatory sequences(act like on/off switches)
-enhancers-turn nearby genes ON more often
-silencers-keep genes off/almost off
2) pseudogenes-inactive(permanently off) +++Gulo gene(why humans need Vitamin C)
3) inactivated viral genes(5-8% of human genes)
-some viruses can insert their DNA into human chromosome
+++HERV K virus
Telomeres
- at both ends of linear chromosomes
- get nibbled away+old over time
Centromeres
- near the middle of each chromosome
- this is where 2 chromatids attach during mitosis and meiosis.
Sister Chromatids
Two identical chromosomes attached to each other during prophase and metaphase
Homologous chromosomes
Two chromosomes that have the same linear order of genes: they are not identical. They have the same genes and the same linear order, but different alleles.
Gene
- a DNA sequence that codes for 1 primary RNA transcript
- codes for different kinds of RNA
- mRNA codes for 1 or more proteins
Allele
- A version of a gene- one gene can have many alleles.
- Somatic cells usually have two alleles for every genes, while gametes usually have one allele for every gene.
Genotype
- The alleles present for an organism for a given gene
- 2 letters! in diploid organisms
Phenotype
- Characteristic that gets expressed
- Words!
- +/- notation
- arg^+ can make arginine
- arg^- can’t
Homozygous
- 2 alleles are the same
- BB or bb
Heterozygous
- “hybrid”
- 2 alleles are different
- Bb, Ab, AB
Dihybrid
-two genes each have two different alleles: AaBb
Haploid
-one set of chromosomes
+++Ex. egg and sperm cells
Diploid
-two sets of chromosomes in cells
Trisomy
-3 of one type of chromosome
-could lead to mutation
+++Trisomy 21 is Down Syndrome
Polyploid
-3 or more sets of chromosomes in cells
Dominant Allele
-One that gets expressed
Recessive Allele
- either non-expressed or not fully expressed.
- deletion means completely recessive
Incomplete dominance
-recessive allele exists and has an effect on phenotype
+++Sickle-cell anemia
Codominance
-both alleles expressed equally
+++Blood type AB makes A+B proteins equally
microRNA
-inhibits protein synthesis
transfer RNA
-brings amino acid to ribosome
messenger RNA
- copy of gene
- conveys genetic info from DNA to ribosome
ribosomal RNA
- RNA in ribosomes
- attaches amino acids to each other
Adenine (A)
Guanine (G)
Cytosine (C)
Thymine (T) - Uracil(U)
C–G
A–T
U replaces T in RNA because it comes apart more easily
Nucleus
The nucleus is an organelle found in eukaryotic cells. Inside its fully-enclosed nuclear membrane, it contains the majority of the cell’s genetic material. This material is organized as DNA molecules, along with a variety of proteins, to form chromosomes.
Enchancers
Enhancer sequences are regulatory DNA sequences that, when bound by specific proteins called transcription factors, enhance the transcription of an associated gene.
located upstream of a gene, within the coding region of the gene, downstream of a gene, or thousands of nucleotides away. When a DNA-bending protein binds to the enhancer, the shape of the DNA changes, which allows interactions between the activators and transcription factors to occur
5’ cap on mRNA
A 7-methylguanosine cap is added to the 5’ end of the pre-mRNA while elongation is still in progress. The 5’ cap protects the nascent mRNA from degradation and assists in ribosome binding during translation. A poly (A) tail is added to the 3’ end of the pre-mRNA once elongation is complete.
B cells
A white blood cell that makes antibodies .
One B cell= 1 specific antibody
Phosphate
A salt of phosphoric acid. Supplement. As a biological molecule, it is composed of phosphorus and oxygen and plays a major role in biological processes of many organisms, e.g. as chemical component of nucleic acids (DNA and RNA), nucleotides (ATP), plasma membrane (phospholipids), etc.Jun 7, 2010
Single stranded binding protein
Single-stranded binding proteins are a class of proteins that have been identified in both viruses and organisms from bacteria to humans.
Transcription start codon
the first codon of a messenger RNA (mRNA) transcript translated by a ribosome. The start codon always codes for methionine in eukaryotes and a modified Met (fMet) in prokaryotes. The most common start codon is AUG. The start codon is often preceded by a 5’ untranslated region (5’ UTR).
Deoxyribose
An aldopentose (i.e. a monosaccharide with five carbon atoms) derived from the pentose sugar ribose by the replacement of a hydroxyl group with a hydrogen atom at the 2 position, leading to the net loss of an oxygen atom
Replisome
The replisome is a complex molecular machine that carries out replication of DNA. The replisome first unwinds double stranded DNA into two single strands. For each of the resulting single strands, a new complementary sequence of DNA is synthesized.
Double helix
the structure formed by double-stranded molecules of nucleic acids such as DNA.
RNA Primase
Primase functions by synthesizing short RNA sequences that are complementary to a single-stranded piece of DNA, which serves as its template. It is critical that primers are synthesized by primase before DNA replication can occur
Helicase
are enzymes that bind and may even remodel nucleic acid or nucleic acid protein complexes. There are DNA and RNA helicases. DNA helicases are essential during DNA replication because they separate double-stranded DNA into single strands allowing each strand to be copied.
Origin of replication
a particular sequence in a genome at which replication is initiated. This can either involve the replication of DNA in living organisms such as prokaryotes and eukaryotes, or that of DNA or RNA in viruses, such as double-stranded RNA viruses.
Leading strand
the two parent DNA strands are separated. One of these is called the leading strand, and it is replicated continuously in the 3’ to 5’ direction. The other strand is the lagging strand, and it is replicated discontinuously in short sections.
Enzyme
Speeds up a chemical reaction
Substrate
earthy material in which an organism lives, or the surface or medium on which an organism grows or is attached
Cell membrane receptor
are receptors that are embedded in the membranes of cells. They act in cell signaling by receiving (binding to) extracellular molecules.
Antibiotics
Antimicrobial agent made from microorganisms, and can kill and inhibit the growth of microorganisms, especially those that are infectious or disease-causing. adjective. Of, relating to, or pertaining to antibiotic
Allosteric site
place on an enzyme where a molecule that is not a substrate may bind, thus changing the shape of the enzyme and influencing its ability to be active
Enzyme-substrate complex
intermediate formed when a substrate molecule interacts with the active site of an enzyme. Following the formation of an enzyme–substrate complex, the substrate molecule undergoes a chemical reaction and is converted into a new produc
Translation
Creation of the complementary strand of DNA
Oncogene
-a proto-oncogene that has been turned on or introduced into the cell by accident causing the cell to become cancer like
Viral oncogene
-an oncogene that a virus inserts into a host cell’s chromosomes making the HC more cancer like.
+++Papilloma(HPV), Epstein-Barr(Mono)
Tumor suppressor genes
Normal genes that produce proteins that inhibit cell division.
+++BRCA-1(breast cancer), p-53(many cancers)
What causes a cell to become cancer like?
Two or more of the following:
1) a proto-oncogene is turned on by mistake(mutation)
2) an oncogene is introduced into the cell by a virus
3) a tumor suppressor gene is turned off by mistake (mutation)
Chemotherapy
-substances given that kill cancer cells but also can kill normal cells
Types of IV drips or pills:
1) Competitive inhibitor of DNA P of other replication enzymes. Causes DNA in fast growing cancer cells to be copied incompletely. Daughter cells die.
-Side effects: hair follicle, taste buds, lining of digestive system, stem cells that become WBC(septus!) all may die
2) Block vessel formation blocker: stop tumor cells from increasing blood supply to tumor. Tumor cells choke and starve.
3) Receptor blocker: blocks certain receptors on cancer cell. Prevents cancer cell from getting message to divide.
B-Cell
- a WBC that makes antibodies
- One b-cell makes one specific antibody
- B stands for Bursa which is one marrow
Major histocompatibility complex(MHC)
- protein in cell membrane
- transmembrane proteins on cell that “display” digested antigen
- it is the WBC that kills antigen
Nucleotide analogs
- A type of competitive inhibitor chemo
- they look like nucleotides, so DNA P attaches to them by mistake and DNA replication stops.
Radiation
- A beam of radiation is aimed into tumor to kill cancers
- often causes formation of other cancers later on
Competitive inhibitor medications
-structure similar to substrate
-binds to active site of enzyme
-stops enzyme from working by blocking substrate
+++Penicilin
Non-competitive inhibitor medication
-binds to enzyme but not at active site
-changes shape of enzyme
-active site closes so substrate can’t bind
+++Integrase inhibitor (anti-viral gene)
Receptor blockers medications
-attach to receptors on cell membrane
-block message molecules from binding
-causes cell to not react to message molecule
+++Benadryl(anti-histamine)
Ribosomes
- made of rRNA and proteins
- location of protein synthesis
- has 2 parts: a small and large subunit
- small subunit binds to mRNA
- large attaches amino acids to each other
Restriction enzymes
- cut DNA at specific sequences called palindromes
- made by and named after bacteria
- usually created ssDNA
Primary protein structure
-made of amino acids which have an amino group (NH2), an acid group (COOH), and a side group (R) on the middle carbon
Structure:
-each amino acid has a 3 letter designation
-primary structure formed by covalent bonds (peptide bonds) between amino acids.
Secondary protein structure
-structure formed from the hydrogen bonds between the C=O of on amino acid and the H-N of another.
Tertiary protein structure
-the overall 3-D structure of a protein-involves the interaction of the amino acid side (R) groups
The following help create it:
-H bonds between R groups
-non-polar R groups staying away from water
-polar of charged side groups moving towards water
-positive side groups attracting negative side groups
Disulphide bond/bridges
- a covalent bond between 2 cysteine amino acids
- it stabilizes the 3-D shape of larger proteins(C-S-S-C)
pBR322
- famous man made plasmid
- codes for tetracycline resistance and ampicillin resistance
- has 2 antibiotic resistant genes: tet^r and amp^r
- an extra gene can be inserted into plasmid
Frameshift mutation
- one or more nucleotide pairs is deleted or inserted causing a different protein to be made
- the codons after insertion change
- this causes the amino acid sequence to change
- a “junk” protein is often made
Mutation
A change in DNA sequence
Point mutation
- One nucleotide pair changes
- may change one amino acid in protein
Insertion/deletion (mutation)
One or more nucleotide pairs inserted/deleted
Inversions(mutation)
A DNA segment is cut out and inserted backwards
Duplication (mutation)
A DNA segment is cut out, duplicated, and reinserted
+++Evolution note: the duplicated gene may mutate and form a new gene coding for a new protein
Transposon
Gene codes for enzyme that allows it to “jump”(cut itself out and randomly reinsert itself somewhere else
Operon
- Special “gene”found in bacteria that codes for 2+ proteins
- have one promoter, one operator(on/off switch), and two or more coding regions
- the coding regions usually code for enzymes that work together in a single biochemical process
Inducible operon
Normally turned off
Gets turned on when needed
Repressive operon
Usually turned on
Gets turned off when not needed
Antigen
A molecule, virus, cell, or parasite that is foreign to body that your body reacts to.
Hydrophobic and Hydrophilic
hydrophobic describes that fact that nonpolar substances don’t combine with water molecule
And
polar groups enabling them to readily absorb or dissolve in water as well as in other polar solvents
RNA anti codons on tRNA
anticodon region of a transfer RNA is a sequence of three bases that are complementary to a codon in the messenger RNA. … The codon AAA specifies the amino acid phenylalanine. You also see the tRNA with the anticodon CCC which is complementary to the codon GGG.
( two definitions )
Translocation
that is a chromosomal segment is moved from one position to another, either within the same chromosome or to another chromosome
( Connection to the Lab )
RNA codons on mRNA
series of codons in part of a messenger RNA (mRNA) molecule. Each codon consists of three nucleotides, usually corresponding to a single amino acid. The nucleotides are abbreviated with the letters A, U, G and C
SnRNPs
small nuclear ribonucleo proteins, are RNA-protein complexes that combine with unmodified pre-mRNA and various other proteins to form a spliceosome
P site
E site
A site
Four binding sites are located on the ribosome, one for mRNA and three for tRNA. The three tRNA sites are labeled P, A, and E. The P site, called the peptidyl site, binds to the tRNA holding the growing polypeptide chain of amino acids.
Hydrogen bonding
electrostatic attraction between two polar groups that occurs when a hydrogen (H) atom covalently bound to a highly electronegative atom such as nitrogen (N), oxygen (O), or fluorine (F) experiences the electrostatic field of another highly electronegative atom nearby.
Charger amino acids
Charged amino acids will decide if they are hydrophilic or hydrophobic
Releasing factor
a protein that allows for the termination of translation by recognizing the termination codon or stop codon in an mRNA sequence.
lysozymes
-an enzyme found in body fluids(tears and mucous) that is capable of breaking down the cell walls of gram positive bacteria b/c it breaks down peptidoglycan
lymphocytes
- any of three subtypes of white blood cell
- They include natural killer cells, T cells (for cell-mediated, cytotoxic adaptive immunity), and B cells.
cytokines
- groups of proteins produced by different cell types that mediate and regulate innate and adaptive immunity
- start inflammatory response
inflammation
- is an immunological defense against injury, infection, or allergy, marked by increases in regional blood flow, immigration of white blood cells, and release of chemical toxins
- prevents body from foreign organisms and repairs tissue trauma
Phaogocytes
-change shape to surround and digest invading microbes(bacteria, viruses)
T-Cell receptor
a molecule found on the surface of T cells, or T lymphocytes, that is responsible for recognizing fragments of antigen as peptides bound to major histocompatibility complex (MHC) molecules
mast cells
- cellular bags of granules located in the loose connective tissues close to blood vessels
- found on the skin, GI, and Resp. lining
- activated through physical injury(ultraviolet light), chemical agents(bee string), immunologic means
macrophage
- Detect and kill invading microorganisms
- Secrete a mixture of cytokines that promote innate/adaptive immune responses
- Control inflammation
- Contribute directly to the repair of damaged tissues by removing dead/dying cells
- Assist the healing process
White blood cells
- aka leukocytes
- help body fight infections and diseases
- type of blood cell made of bone marrow and found in the blood and lymph tissue
perforin
- Protein that inserts in plasma membrane of target cells
- creates channels that allows ECF into cell
- causing cell to burst (cytolysis)
MHC class I proteins
- present on the surface of all nucleated cells
- interact with cytotoxic T cells
- Consists of two non-identical chains: a long alpha chain and a short beta chaiin
MHC class II proteins
- present on the surface of antigen presenting cells such as macrophages and B Cells
- interact with helper T cells
- -Consists of two roughly identical chains: an alpha chain and a beta chain
V, J, C, D regions
- The loci encoding immunoglobulins have a unique structure
- composed of “gene segments” - The heavy chain locus has multiple V (variable) segments, multiple D (diversity) segments, multiple J (joining) segments and multiple C (constant) segments.
- During maturation, one of each V, D and J segment is randomly “chosen” and used to encode the final antibody molecule.
Helper T Cells
- help B cells produce antibodies to protein antigens
- promote activation and proliferation of other T cells
Cloning a mammal
1) remove nucleus from an egg cell(ENUCLEATION)
2) remove a diploid cell from mammal to be cloned
3) place diploid cell next to enucleated egg cell
4) shock the two cells so they fuse into 1 cell
5) the fused cell acts like a fertilized egg aka zygote
6) place newly made zygote into receptive uterus
Complementation
When two organisms with recessive phenotypes produce an offspring with a dominant phenotype
antibodies
- Y shaped proteins that attach to antigens
- held together by DISULPHIDE BONDS
- they label antigen as foreign
- they don’t kill antigen.
- they are antigen specific
- one antibody to one antigen
constant region of antibody
-determines the function of the antibody
variable region of antibody/antigen binding site
-determines the antibody’s specificity (no known effector function)
short chain proteins
-the end product of protein digestion(along with a.a.) that can be taken up by the absorptive cells of the small intestine
histamine
a compound that is released by cells in response to injury and in allergic and inflammatory reactions, causing contraction of smooth muscle and dilation of capillaries
interferon
-various proteins produced by virus-infected cells that inhibit the reproduction of the invading virus and induce resistance to further infection
memory B cells
- responsible for humoral immunity during adaptive immune response
- at the time of a 2nd infection the cells remember how to fight it
- produce more functional antibody
killer/cytotoxic T cells
- Directly attack & kill cells
- Can destroy all infected or abnormal cells
- They bind to a self-non-self complex
- they look for body cells displaying antigen they recognize
