Unit 5 Review Honors Biology DNA structure replication

Unit 5 Review Honors Biology

DNA structure & replication OBJECTIVE 1

Covered by: �POGIL worksheet (okay to use in portfolio since we did not do the lab)

Structure & Function � In nucleus (eukaryotes) – never leaves � Nucleotides ◦ Monomer of DNA ◦ Deoxyribose sugar, phosphate, nitrogen base � Base pairs ◦ Adenine – Thymine ◦ Guanine – Cytosine � Double stranded helix � Codes for proteins – very important molecule!

Replication �Copy DNA exactly to pass to daughter cells (for mitosis) �Necessary for each cell to have full set of instructions to make proteins

Gene expression OBJECTIVE 2

DNA vs. RNA vs. Protein �DNA codes for proteins ◦ Ex: “boss” �RNA helps make the protein ◦ Ex: “workers” �Protein ◦ Monomer – amino acid ◦ Proteins have many functions… think of your projects! ◦ Ex: “product”

RNA Structure �In nucleus (eukaryotes) and cytoplasm/ribosom es �Nucleotides ◦ Monomer of RNA ◦ Ribose sugar, phosphate, nitrogen base �Base pairs ◦ Adenine – Uracil (NO THYMINE) ◦ Guanine – Cytosine �Single helix stranded

Types of RNA �m. RNA – messenger ◦ Carries DNA message to ribosome �t. RNA – transfer ◦ Transfers amino acids to ribosome �r. RNA – ribosomal ◦ Where amino acids are assembled to make protein

Transcription �DNA is transcribed (copied) into a m. RNA sequence �m. RNA leaves nucleus to carry code to ribosome �Animation

Translation �m. RNA goes to a ribosome, t. RNAs bring in amino acids to make a protein �Animation

Gene Expression �Only genes for proteins a cell needs will be expressed

Mitosis & Meiosis OBJECTIVE 3

Haploid vs. Diploid � -ploid = sets of chromosomes � Diploid = 2 sets of chromosomes (2 n) ◦ Somatic (body) cells ◦ Made by mitosis ◦ Ex: human skin cell 2 n= 46 (2 sets of 23) � Haploid = 1 set of chromosomes (1 n) ◦ Gametes (sperm and egg) ◦ Made by meiosis ◦ Ex: human sperm cell 1 n=23 (1 set of 23)

Mitosis �Allows for growth of organisms (somatic = body cells), asexual reproduction �Produces 2 identical cells to parent ◦ Chromosome # in parent cell = chromosome # in daughter cells �Diploid cells diploid cells

Meiosis �Allows sexually reproducing organisms to make gametes (sperm, egg) �Produces 4 haploid, genetically different cells ◦ Crossing over = genetic variation ◦ Chromosome # in daughter cells is HALF the chromosome # in parent cell �Diploid cells haploid cells

Stem cells, differentiation, & specialization OBJECTIVE 4

�Specialization ◦ Cells take on specific jobs ◦ Ex: neuron �Differentiation ◦ When a cell becomes specialized, expresses specific genes for its type �Stem cells ◦ Unspecialized cells capable of differentiating into any cell type

DNA, genes, & chromosomes OBJECTIVE 5

DNA, Genes, & Chromosomes

“Forms” of DNA �Chromosomes – DNA sequences that are made of genes coding for protein �Chromatin – condensed DNA (not visible) �Chromatids – visible replicated chromosomes during cell division

Genetic variation OBJECTIVE 6

Variation comes from: �Meiosis/sexual reproduction ◦ Crossing over, random fertilization �Errors in DNA replication ◦ Substitution, deletion, insertion �Environmental factors