Biology Review Benchmark Test 3 Standards 4 A

Biology Review Benchmark Test #3 Standards 4 A, 4 B, 4 C, 4 D • • 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 double helix me so o m ro h dc ate c pli du sister chromatids coils centromere nucleosome supercoils histone proteins

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. 1. ____________ - process of DNA being copied into m. RNA. – Occurs in the ___________ of a cell 2. ____________ - process of synthesizing proteins by using RNA. – Occurs at the ___________ of a cell

Protein Synthesis DNA -----> m. RNA -----> Protein

3 Types of RNA _____ m. RNA _____r. RNA _____t. RNA a) carries amino acids to ribosome b) form ribosomes c) copy of instructions; complementary to DNA Ribosomal RNA Messenger RNA Transfer RNA

Protein Synthesis _____________ DNA RNA Amino Acid T A C T G C A G 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 Nucleic Acid Composed of Nucleotides Single Stranded Double Stranded Genetic Material Phosphate Pentose 5 C Sugar Deoxyribose Ribose A, G, C Uracil Thymine RNA

Meiosis

Sequence Meiosis I and II 1) ___ 2) ___ 3) ___ 4) ___ 5) ___ 6) ___ 7) ___ 8) ___

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

Mitosis and Meiosis

Comparing Mitosis & Meiosis Mitosis 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 Meiosis

Comparing Mitosis & Meiosis Mitosis 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 Meiosis

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