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Biology 4A
Prokaryotes & Eukaryotes
All living cells can be divided into two groups:
- Prokaryotic cells – simple cells
- Single-celled organisms (bacteria and blue-green algae)
- Eukaryotic cells – more complex cells
- Single-celled organisms (protists)
- Compose multi-cellular organisms (protists, fungi, plants and animals) Feature Function Prokaryotes Eukaryotes Cell (plasma) membrane Regulate material entering and exiting cell All All DNA Stores genetic material All All Cell wall Protect cell, provide shape All Some (plants) Cytoplasm Fluid inside cell All All Nucleus Houses DNA None All Ribosomes Site of protein synthesis All All Flagella Aid cell in locomotion Some Some Mitochondria Site of ATP synthesis None All Endoplasmic Reticulum Synthesis of proteins and lipids None All Golgi apparatus Storage and packaging of substances None All Lysosomes & Peroxisomes Digest particles None All Vacuoles Storage of material Some Some Plasmids Small pieces of DNA that can exit the cell Some None Plastids Contain food or pigments None Some (plants)
Biology 4A
Prokaryotes & Eukaryotes
Prokaryotic Bacterial Cell Eukaryotic Plant Cell Eukaryotic Animal Cell
Biology 4B
Cellular Processes
Synthesis of New Molecules DNA Replication
- Helicases unwind and unzip DNA at replication forks
- Free floating nucleotides bond to exposed bases
- DNA polymerase bind nucleotides to each other in 5’ to 3’ direction a. Leading strand – elongates toward replication fork continuously b. Lagging strand – elongates away from replication fork discontinuously (called Okazaki fragments), bonded together by DNA ligase
- New molecules each contain one original and one new strand Transcription – process by which a portion of DNA nucleotide sequence is used to produce a complementary mRNA strand by RNA polymerase Translation – process by which information in mRNA strand is used to create amino acid chain (polypeptide chain) by ribosomes and tRNAs Lipogenesis – process of synthesizing lipids from intermediates of cellular respiration, occurs along smooth endoplasmic reticulum
Biology 4B
Cellular Processes
Transport of Molecules Intracellular transport – within the cell
- Many molecules float freely through cytoplasm
- Others are carried by motor proteins (kinesin) or the endoplasmic reticulum and Golgi apparatus Intercellular transport – in and out of the cell through plasma membrane Passive transport – does not use energy, movement down concentration gradient (high to low concentration)
- Diffusion – net movement of small, nonpolar molecules directly through phospholipid bilayer
- Facilitated diffusion – net movement of larger molecules and ions through ion channels or carrier proteins
- Osmosis – net movement of water molecules through membrane Active transport – uses energy (ATP), movement up concentration gradient (low to high concentration)
- Ion pumps – proteins that move ions one way
- Cotransport – coupled passage of two molecules in the same direction (symport) or different directions (antiport) Homeostasis – ability of a cell to maintain stable internal conditions independent of environment, accomplished by passive and active transport
- Carbonic acid – buffer that helps regular pH
Biology 4C - Viruses Biology 4C
AIDS
- Loss of immune system effectiveness
- Caused HIV - human immunodeficiency virus
- Period of dormancy before loss of immune system
- Prevention
- No vaccine (yet)
- Limit and avoid transmission The Common Cold
- Fever, fatigue, and respiratory infections
- Caused a variety of rhinoviruses
- Prevention
- No vaccine
- Limit transmission Influenza (the flu)
- Fever, fatigue, and respiratory infections
- Can be deadly
- Caused a variety of influenza viruses
- Can mutate rapidly and blend together
- Prevention
- Seasonal vaccine
- Limit transmission Hepatitis A
- Inflammation of liver, jaundice (yellow) appearance
- Caused a hepatitis A virus in food and water
- Prevention
- Vaccine
- Limit transmission Human Viral Diseases
Biology 5A
Cell Cycle
Cell cycle – the sequence of cell growth and division that occurs in a cell between the beginning of one cell division and the beginning of next cell division
- Interphase (G1, S, G2) – period in which cell prepares for division. DNA and organelles replicate.
- Mitotic phase (mitosis and cytokinesis) – period in which cell divides into two daughter cells. Ensures that daughter cells receive correct number of chromosomes.
Biology 5A
Cell Cycle
DNA replication – the process by which DNA is copied into a new strand, occurs during S phase of interphase
- Semiconservative replication – each new molecule contains one original and one new strand
- Helicase unwinds DNA and break hydrogen bonds between complementary base pairs o Replication fork – site which separation occurs
- Free-floating nucleotides bond to exposed bases (A & T, C & G)
- DNA polymerase bond nucleotides to each other in 5’ to 3’ direction o Leading strand: elongates continuously toward replication fork o Lagging strand: elongates discontinuously as Okazaki fragments away from replication fork, sealed by DNA ligase Why is the cell cycle important?
- Cells are limited in size. Large organisms need to be multicellular. Proper cell division ensures daughter cells have correct DNA
- Mode of reproduction for unicellular organisms
- Mode of growth, maintenance, and replacement for multicellular organisms
Biology 5B
Specialized Cells
Specialized Plant Cells Cell Feature Function Root cells Concentric circles of vascular tissue Transport water and minerals upward Root cells Hairs protruding from cell walls Absorb water and minerals from soil Stem cells Concentric circles of vascular tissues Transport water and minerals throughout plant Stem cells Thick-walled cells around outer edge Provides support Leaf cells Cells have many chloroplasts, arranged in layers Carry out photosynthesis Specialized Animal Cells Cell Feature Function Red blood cells Contain hemoglobin Deliver oxygen to body cells Muscle cells Contain filaments that can contract Cause movement of body parts or substances Epithelium cells (exterior skin) Cells packed tightly together Form a protective cover Epithelium cells (internal lining) High surface area Exchange molecules Nerve cells Contain dendrites and axon Transmit electrical signals throughout body
Biology 5 D
Cell Cycle and Cancer
Cell cycle – the sequence of cell growth and division that occurs in a cell between the beginning of one cell division and the beginning of next cell division
- End of G1 – vital checkpoint, cell determines whether or not to replicate its DNA o Mutations in growth- regulating genes cause cells to divide more rapidly Growth regulating genes Proto-oncogenes – encode proteins that stimulate cell division in normal cells
- Mutation Oncogenes – mutated proto-oncogenes that speed up cell division Tumor suppressor genes – encode proteins that turn off cell division in normal cells
- Mutation Mutated suppressor genes fail to turn off cell division Tumors and cancer Tumor – dense mass of abnormal cells
- Result of mutations in growth-regulating genes
- Benign – localized tumor, cells do not invade other tissues
- Malignant – cells of tumor do not remain in one area, migrate and invade other tissues Cancer – condition in which malignant cells invade and destroy body tissues
- Develops overtime due to genetic changes
- Can be stimulated by carcinogens
DNA
Components of DNA Deoxyribonucleic acid (DNA) is a double-stranded macromolecule, made of building blocks called nucleotides Each nucleotide contains a
- Phosphate base
- Deoxyribose sugar
- Nitrogenous base Bonding in DNA
- The sides of one DNA molecule is connected with bonds between the phosphate group and the deoxyribose sugar
- The two DNA strands connect by bonds between nitrogenous bases o A always bonds with T o G always bonds with C Role of DNA DNA is the genetic material of organisms.
- Information coded in the order of the bases used to create proteins
- Proteins act as enzymes, cell signals, and structural elements, contributing to the traits seen in organisms.
- Different DNA can lead to different proteins Biology 6A
Transcription & Translation
How is DNA used to create proteins?
- Transcription – process by which DNA is used to produce mRNA a) RNA polymerase – protein that initiates and operates transcription b) mRNA – messenger RNA, carries information into cytoplasm Use the steps below to determine an mRNA strand sequence.
- Editing and processing – process of modifying mRNA in eukaryotes a) introns removed b) exons spliced together c) cap and tail added d) sent out of the nucleus Biology 6C
How is DNA used to create proteins (cont.)?
- Translation – process by which information in mRNA strand is used to create amino acid chain (polypeptide chain) a) Ribosome – protein complex where translation occurs, made of rRNA b) tRNA – transfer RNA, bring amino acids to the ribosome Use the steps below to determine a polypeptide chain sequence.
- Editing and folding a) editing – sections of polypeptide chain removed b) folding – chain folds to make 3D shape, critical for protein function Biology 6C
Transcription & Translation
Biology 6E
DNA Mutations
Mutation – a random change in the sequence of a gene, caused by mistakes in DNA replication process and environmental agents. Mutation Definition Example Point mutation (Substitution) One base replaced with another base ABCDEFG AB Z DEFG Inversion Order of two or more bases reversed ABCDEFG AB EDC FG Insertion Addition or one or more new bases ABCDEFG ABC H DEFG Deletion Removal or one or more bases ABCDEFG ABEFG CD Translocation Movement of one or more bases to a new location in a different DNA sequence ABCDEFG ABCDEFG AB EFG ABCD CDEFG Determine effect of mutation during translation
- Determine amino acid chain made by original mRNA strand
- Determine amino acid chain made by mutant mRNA strand
- Compare the two chains a. No changes = silent mutation b. One amino acid changed = missense mutation c. Amino acid chain ends sooner = nonsense mutation d. Multiple amino acids changed = frameshift mutation Mutation in traits can be organized by their effect
- Neutral mutations – no effect on survival (eye color)
- Harmful mutations – decrease survival (cancer)
- Beneficial mutations – increase survival (disease resistance)
You can use the five steps below to solve any genetics problem Vocabulary Biology 6F - Genetics and Punnett Squares character - a recognizable feature controlled by genetics (ex: fur color) trait - a version of a character (ex: white fur) allele - the section of DNA that codes for a specific trait genotype - an organism’s genetic makeup for a character (ex: Ww) phenotype - an organism’s appearance for a character (ex: white fur) homozygous - having two of the same alleles for a character (ex: WW) heterozygous - having two different alleles for a character (ex: Ww) Types of dominance
- complete dominance - heterozygous individuals display dominant trait
- incomplete dominance - heterozygous individuals display an intermediate between traits
- codominance - heterzygous individuals display both traits at once Punnett Squares Organize outcomes from genetic crosses Each box represents an equally likely outcome G g G g GG Gg Gg gg GR Gr gR^ gr G R G r g R g r GGRR GGRr GGRr GgRr GgRr GgRr GgRr GgRR GGrr GgRR ggrr ggRr ggRr ggRR Ggrr Ggrr Biology 6F
