Ap Biology

• DNA( deoxyribonucleic acid) is a type of nucleic acid. A nucleic acid is a polymer of nucleotides.
• The backbone of DNA is made up of a combination of sugar and phosphate.
• The sugar that makes up the backbone is deoxyribose.
• The phospate group is acidic and thats where you get acid from deoxyribonucleic acid.
• And nucleic is that it was found in the nuclei of the cells.
• For every acid it has a base, and those bases form the rung of ladders.
• Each rung is a pair of bases.
• Phosphates have a negative oxygen meaning that oxygen is losing hydrogens. This means that phosphates are acidic. The word acidic comes from the word ( Deoxyribonucleic acid)
• Chromosomes are made up of DNA and protiens ( histones )

  
• In eukaryotes, DNA is typically broken up into a number of very long, linear pieces called chromosomes
• in prokaryotes such as bacteria, chromosomes are much smaller and often circular (ring-shaped).
• RNA is a single helix, while DNA is a double helix
• DNA polyerase is an enzyme that adds new bases or new nucleotides to the DNA
• An enzyme called helicase unwinds the DNA strand in an area called the origin of replicatian or ori site.
• Central Dogma is how DNA make us. DNA makes RNA which is known as transcription. RNA makes protien. Protiens makes phenotypes. Phenotypes makes us.
• The enzmye helicase seperates hydrogen bonds between base pairs.
• Helicase enzyme creates a replication fork/buble and unwinds the DNA helix.

  
• The separated strands each provide a template for creating a new strand of DNA.

  
• An enzyme called primase starts the proccess.

  
• George Beadle and Edward Tatum proposed the one gene-one enzyme hypothesis in 1941. This proposes that a single gene has the genetic information for making one enzyme. This was later changed to become the one gene - one polypeptide (protein) hypothesis; as enzymes are a TYPE of polypeptide (protein).
• The DNA molecule is composed of two strands of nucleotides held together by hydrogen bonds. Each strand has two slightly different ends. One end, known as the 5’ end, terminates with an unbound 5’ carbon on the last nucleotide in the chain. The other end, known as the 3’ end, terminates with an unbound 3’ carbon on the last deoxyribose molecule at its end.

  
• The telomere shortening mechanism normally limits cells to a fixed number of divisions, and animal studies suggest that this is responsible for aging on the cellular level and sets a limit on lifespans. Once a cell’s telomeres reach a certain level of shortness, the cells typically undergo apoptosis or programmed cell death. This prevents them from replicating with missing genetic sequences.

  
• Telomerase is an enzyme which lengthens telomeres during fetal development. After the fetus is fully developed, this enzyme shuts off and degrades over time. The gene that is responsible for producing the enzyme is heavily methylated and permanently deactivated before birth. The telomerase enzyme can become active again in some mutated cells and can lead to cancer. This condition leads to abnormally fast growth and reproduction in cells. These cells essentially become immortal and can continue to reproduce an unlimited number of times.
• The function of DNA is to code for the body’s proteins. Proteins make up a large part of the body’s structure and are responsible for many of its functions.

  
• The ribosome is made out of rrna ( ribosomal rna)
• During translation in the cytoplasm there are trnas which carry amino acids. Amino acids is the monomer of a protein. The trna will bring the amino acids together to make that. The mrna is going to direct them to the rna strand created from the dna strand.
• The trna match the rna strand

  
• The tran leaves when connected to the rna strand but the amino acids stay and the trnas go to pick up another amino acid. The amino acids areconnected to each other by peptide bonds. The stond condon stops the process. The result of translation is that you have a chain of amino acids based on the coding of mrna. The mrna was complementary to the DNA.
• Transctiption occurs in the nucleus of a cell and is the process of transferring information from DNA to RNA.