translation transcription dna meiosis mitosis

The ribosome reads mRNA three bases at a time, known as a codon.

tRNA molecules transport specific amino acids to the ribosome to match the mRNA sequence.

A complementary anti-codon on the tRNA binds to the corresponding codon on the mRNA.

Once the tRNA is bound, it releases the amino acid, which then forms peptide bonds with other amino acids as the process repeats for each codon.

the study of changes in gene expression

in env factors that can cause genomic changes that are inherited by offspring that do not alter DNA sequence

Addition of an acetyl group (CH₃CO) to the histone protein tail causes the chromatin to relax or unwind.

This relaxation exposes the DNA, promoting transcription.

The open chromatin structure facilitates transcription, allowing RNA polymerase to access nucleotides needed to synthesize mRNA.

<p>Nucleus controls all cellular activities</p> <p>produces ribosomes, which are used for protein synthesis</p> <p>nucleus has receptors for inducing protein synthesis</p> <p>nucleus transmits mRNA to attach to ribosome</p> Signup and view all the answers

<p>Helicase: separates two strands of DNA molecule</p> <p>Polymerase: adds new nucleotides to create new DNA strand</p> Signup and view all the answers

<p>-epigenetics is the altering of gene expression without changing the gene structure due to environmental factors -modifications are attached to DNA coiling structures to relax chromatin (switch on) or tighten (switch off) protein production</p> <p>ACETYLATION -addition of acetyl group (CH3CO) tags to histone protein tail -tags relax structure of chromatin -promotes transcription -by allowing RNA polymerase to easily access nucleotides -enhancing gene expression</p> <p>DNA METHYLATION -methyl group (CH3) tags added to histone protein tail -at CpG sites (where a cytosine nucleotide is adjacent to a guanine) -tags tighten structure of chromatin -restricting access of RNA polymerase to DNA -inhibiting gene expression</p> Signup and view all the answers

<p>Must include description of translation, initiation, elongation, termination</p> <p>-Translation: “decoding” a messenger RNA (mRNA) and using its information to build a polypeptide, or chain of amino acids -occurs in cytoplasm</p> <p>-initiation: triplet code on mRNA read by tRNA to collect correct amino acid from cytoplasm to add to the sequence at the ribosome -ribosome binds to mRNA -ribosome reads mRNA 3 bases (a codon) at a time -start codon (AUG) initiates process</p> <p>-elongation: addition of amino acids to the protein chain at the ribosome -tRNA molecules carry amino acid to mRNA -complementary rTNA anti-codon matches with mRNA codom -tRNA releases amino aid -peptide bonds form between amino acids (process is repeated for each codon) -polypeptide chain forms</p> <p>termination: when a &quot;stop&quot; codon appears no amino acid is added to the sequence so the protein chain ends; no tRNA to match that combination -peptide chain is released from ribosome -protein goes to Golgi body for processing in complete protein -proteins are folded into appropriate 3D shape and AUG removed</p> Signup and view all the answers

<p>similarities: both double stranded both have same nucleotides same complementary base pairing (AT and CG)</p> <p>differences: mtDNA is in mitochondria whereas nDNA is in nucleus mtDNA is much smaller and is circular whereas nDNA is larger and double helix mtDNA only inherited from mother whereas nDNA is inherited from both mother and father</p> Signup and view all the answers

<p>importance: meiosis- produce sex cells mitosis- need for growth and repair of cells</p> <p>similarities: both start wth diploid cell both are types of cell division DNA replication occurs before both processes take place sister chromatids separate (to opposite poles) in mitosis and meiosis II</p> <p>differences: mitosis: daughter cells identical meiosis: daughter cells are not identical</p> <p>mitosis: one division meiosis: two divisions</p> <p>mitosis: results in two diploid daughter cells meiosis: results in four haploid daughter cells</p> <p>mitosis: homologous chromosomes do not pair meiosis: homologous chromosomes pair (in meiosis I)</p> <p>mitosis: no crossing over and/or independent assortment meiosis: crossing over and/or independent assortment occur (in meiosis I)</p> Signup and view all the answers

<ol> <li>DNA is made up of two (anti-parallel) strands of nucleotides/ double-stranded</li> <li>Nucleotides made up of a phosphate group, a deoxyribose sugar and a nitrogenous base (diagram accepted, if accurate)</li> <li>The sugar of one nucleotide bonds with the phosphate of another/ there is a long chain of alternating sugar and phosphate molecules for each DNA strand /sugar-phosphate backbone</li> <li>Attached to each sugar is a nitrogenous base (diagram accepted)</li> <li>The base pairs are held together by hydrogen bonds</li> <li>Adenine only bonds with thymine, cytosine only bonds with guanine (full names only)</li> <li>The DNA twists into a double helix shape</li> </ol> <p>WHY STRUCTURE ALLOWS FOR REPLICATION OF DNA 8. Hydrogen bonds between bases are relatively weak and easily broken (by DNA helicase) 9. This means the nitrogen bases are easily exposed to allow for replication to occur</p> Signup and view all the answers

<ol> <li>Helicase: break hydrogen bonds between DNA strands</li> <li>DNA Polymerase: synthesises DNA strand from nucleotides/ creates sugar-phosphate backbone</li> <li>DNA Ligase: joins Okazaki fragments of DNA together</li> </ol> Signup and view all the answers

<ol> <li>Both have same basic structure: base, sugar, phosphate</li> <li>(Generally) DNA double-stranded whereas RNA is single-stranded</li> <li>DNA has thymine whereas RNA has uracil</li> <li>DNA has deoxyribose sugar whereas RNA has ribose sugar</li> <li>(Generally) DNA is longer whereas RNA is shorter</li> </ol> Signup and view all the answers

<p>Transcription: reading the DNA code to produce the mRNA in the nucleus. Or similar. Any five of the following for TRANSCRIPTION:</p> <ol> <li>occurs in the nucleus</li> <li>because DNA too big to leave nucleus through the pores</li> <li>enzymes stated: RNA polymerase OR helicase (NELSON: book states helicase, both answers acceptable)</li> <li>RNA polymerase (helicase) separates / splits the DNA strand / H-bonds temporarily</li> <li>one DNA strand acts as a template (to make a coding mRNA strand)</li> <li>RNA nucleotides pair up with complementary base / A pairs with U, G pairs with C</li> <li>RNA polymerase joins RNA nucleotides together / creates sugar-phos backbone</li> <li>mRNA moves out of nucleus through nuclear pores</li> </ol> Signup and view all the answers

<p>Translation: process to produce proteins from mRNA code OR “decoding” a messenger RNA (mRNA) and using its information to build a polypeptide, or chain of amino acids. Or similar.</p> <ol> <li>Initiation: triplet code on the rRNA read by the tRNA to collect the correct amino acid from the cytoplasm to add to the sequence at the ribosome</li> <li>Elongation: tRNA adds of amino acids to the protein chain at the ribosome, where its anti-codon is complementary to the codon of the mRNA; peptide bonds form between amino acids.</li> <li>Termination: when a ‘stop’ codon appears no amino acid is added to the sequence, so the protein chain ends; no tRNA to match that combination. the protein is then sent to Golgi body for modification/finishing into a complete protein</li> </ol> Signup and view all the answers