Biology Review Benchmark Test #3 Standards 4A, 4B, 4C, 4D DNA, Genes, Chromosomes DNA Replication Protein Synthesis Biotechnology Meiosis Genetics Mutations

DNA DNA is considered the code of life because it codes for ________________. (TRUE or FALSE) Organisms that are closely related share more similar DNA sequences compared to organisms not closely related. Circle the two DNA strands most likely related: ATGCGGTTA TAACGTACC CATTAAGGC AGCTGCAAT ATGCGGTAA GCAGCTCTG

Chromosomes __________________________ - structure in the nucleus of cells that consist of one long molecule of DNA condensed & coiled around proteins. Chromosomes contain sections of DNA called _____________ which code for _______________. Humans have ______ chromosomes arranged in ______ pairs  _____ autosomes & _____ sex chromosomes (X or Y)

DNA Gene – section of DNA DNA double helix duplicated chromosome coils centromere sister chromatids supercoils coils histone proteins nucleosome DNA double helix

DNA Replication ____________________________ - copying DNA. (TRUE or FALSE) Occurs during S phase of Interphase. Replication produces _____ identical copies of DNA molecules. (TRUE or FALSE) Each DNA molecule copied contains 1 strand of old DNA & 1 strand of new DNA. (TRUE of FALSE) Enzymes involved in DNA replication.

Steps of DNA Replication Double helix unzips and then complementary base pairs are added (A-T and C-G)

Protein Synthesis (TRUE or FALSE) Protein synthesis involves transcription and translation. _______________________ - process of DNA being copied into mRNA. Occurs in the _____________________ of a cell _______________________ - process of synthesizing proteins by using RNA. Occurs at the _____________________ of a cell

Protein Synthesis DNA ----------> mRNA ----------> Protein

3 Types of RNA _____ mRNA a) carries amino acids to ribosome _____rRNA b) form ribosomes _____tRNA c) copy of instructions; complementary to DNA Messenger RNA Ribosomal RNA Transfer RNA

Protein Synthesis DNA RNA Amino Acid T A C G __________________________ DNA RNA Amino Acid T A C G __________________________

Mutations ______________________ - change in DNA (TRUE or FALSE) Mutations can result from a malfunction during mitosis or meiosis. (TRUE or FALSE) Most mutations are automatically repaired by an organism’s enzymes. If the mutant cell is a body cell, the daughter cells can be affected resulting in the mutation (being passed, not being passed) to the offspring. If the mutant cell is a gamete, the daughter cells can be affected resulting in the mutation (being passed, not being passed) to the offspring.

Types of Mutations _____________ Mutations – affects a single gene ________________ Mutations – affects chromosomes Point Mutation  substitution, addition, or removal of a single nucleotide Frameshift Mutation  addition or deletion of nucleotide (TRUE or FALSE) Mutations may be beneficial.

DNA or RNA? DNA RNA Nucleic Acid Composed of Nucleotides Single Stranded Double Stranded Genetic Material Phosphate Pentose 5 C Sugar Deoxyribose Ribose A, G, C Uracil Thymine

Meiosis

Sequence Meiosis I and II ___

Crossing Over ___________________ - homologous chromosomes exchange DNA. (TRUE or FALSE) Crossing over increases genetic variation. Crossing over occurs during ___________________.

Mitosis and Meiosis

Comparing Mitosis & Meiosis Produces more cells Body cells Produces haploid cells Sexual Reproduction Sperm & Egg Gametes Genetically identical cells Produces diploid cells Increases genetic variation Sex cells Somatic cells Genetically different cells Asexual Reproduction

Comparing Mitosis & Meiosis TWO divisions DNA from one parent Occurs in ALL organisms “Crossing Over” Occurs in many organisms DNA from two parents Reduces chromosome number Maintains chromosome number ONE division Produces cells with 23 chromosomes TETRAD Skin cells, liver cells, hair cells Produces cells with 46 chromosomes

Comparing Haploid and Diploid How many chromosomes in …… “Normal” Human 1) n cells? 2) Diploid cells? 3) Gamete cells? 4) Cells that asexually reproduce? 5) Somatic cells? 6) Sex cells? 7) Haploid cells? 8) 2n cells? 9) Sperm cells? 10) Cells that sexually reproduce?