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