increase in the production of functional ribosomes 5A secreteory cell cell that

Increase in the production of functional ribosomes 5a

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increase in the production of functional ribosome’s 5. A secreteory cell (cell that secretes proteins) will have a lot of bound ribosomes and a prominent rough ER, golgi and high numbers of nucleoli in the nucleus 6. Cell is actively synthesizing cytosolic proteins= a lot of free ribosomes; lot of nucleoli in the nucleus The Nucleus: Chromatin 1. Composed of DNA and the histone proteins 2. Consists of structural units called NUCLEOSOMES 3. Each nucleosome is composed of 8 globular histone proteins connected by the thread-like DNA a. With DNA wrapped around b. Nucleosome are the repeated units of chromatin 4. 2 types of chromatin: a. Heterochromatin – condensed, inactive chromatin b. Euchromatin – extended, active chromatin 5. Function of histone protein a. Act as structural framework to support the delicate thread-like DNA a.i. Prevent the DNA from breaking and twisting b. Regulate/control the activities of DNA (transcription and DNA replication) c. When DNA is wrapped around histone proteins DNA is condensed and inactive and the chromatin is referred to as heterochromatin d. DNA becomes active only when it unravels from the histone protein and it assumes the extended form called euchromatin= for DNA replication and transcription Nucleic Acids 1. Organic compound in the human body 2. Nucleotides: phosphorus, ribose sugar (deoxyribose or ribose) or nitrogen containing base 3. Nitrogen containing bases: thymine (T), guanine (G), adenine (A), uracil (U), cytosine (C) 4. DNA consists of structural units called NUCLEOTIDES 5. Each nucleotide is composed of a. Pentose sugar a.i. Deoxyribose a.ii. Ribose b. Nitrogen-containing base b.i. A,G, C, T, U c. Phosphate group 6. 2 Types of Nucleic Acids: a. Deoxyribonucleic Acids = DNA b. Ribonucleic Acids = RNA 7. DNA a. Double helical structure 2 polynucleotide chains twisted to form a staircase-like structure
13 b. Contains pentose sugar deoxyribose c. Nitrogen bases: T, G, C, A 8. RNA a. Single stranded structure b. Composed of 1 polynucleotide chain c. Contains ribose d. Nitrogen bases: U, A, G, C 5 Nitrogen-containing Bases 1. Adenine “A” Purines 2. Guanine “G” 3. Cytosine “C” 4. Thymine “T” Pyrimidines 5. Uracil “U” 6. DNA contains 4 bases – A, G, C, T 7. DNA is a double helix 8. According to the law of Complementarity… a. “A” always forms a covalent bond with “T b. “C” always forms a covalent bond with “G” The Cell Cycle 1. The series of events a cell undergoes from the time it’s formed until it reproduces 2. Consists of 2 major sequential periods: a. Interphase: consists of 3 sequential phases: G1, S, G2 a.i. G1 phase: longest phase; protein synthesis; cell growth a.ii. S phase: DNA replication is the main event ( next slide) a.iii. G2 phase: protein synthesis especially those required for the initiation/maintenance of mitosis b. Cell division: 2 sequential phases: mitosis and cytokinesis b.i. Mitosis: Nuclear division b.i.1. 4 sequential subphases: Prophase, Metaphase, Anaphase, Telophase b.ii. Cytokenesis: Cytoplasmic division SEMI-CONSERVATIVE REPLICATION: Each daughter DNA consists of an old strand and a newly

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