Objective 2:demonstrate an understanding of the organization of livingsystems. Biology of the Individual
The Very Basics, Cells Know that cells are the basic structures of all living things and have specialized parts that perform specific functions, and that viruses are different from cells and have different properties and functions.
Investigate and identify cellular processes including homeostasis, permeability, energy production, transportation of molecules, disposal of wastes, function of cellular parts, and synthesis of new molecules.
Schematic of typical animal cell, showing subcellular components. • Organelles: (1) nucleolus (2) nucleus (3) ribosome (4) vesicle (5) rough endoplasmic reticulum (ER) (6) Golgi apparatus (7) Cytoskeleton (8) smooth ER (9) mitochondria (10) vacuole (11) cytoplasm (12) lysosome (13) centrioles
Chromosomes • A chromosome is an organized structure of DNA and protein that is found in cells. • It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. • Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions. • The chromosomes are located in the nucleus. • Humans have 23 pairs.
Gene • A gene is the basic unit of heredity in a living organism. • All living things depend on genes. • Genes hold the information to build and maintain an organism's cells and pass genetic traits to offspring. • Genes are located on the chromosomes.
Organelles • In cell biology, an organelle is a specialized subunit within a cell that has a specific function, and is usually separately enclosed within its own lipid membrane. • A very small organ. It has a specific job to do.
Nucleolus • The nucleolus is a non-membrane bound structure composed of proteins and nucleic acids found within the nucleus.
Nucleus • the nucleus is sometimes referred to as the "control center“ of the cell, is a membrane-enclosed organelle found in eukaryotic cells. • It contains most of the cell's genetic material, organized as multiple long linear DNA molecules in complex with a large variety of proteins to form chromosomes. • It holds the instructions for the cell.
Ribosomes • Ribosomes are the components of cells that make proteins from amino acids. • They are located outside the nucleus. • mRNA travels to the ribosomes to meet with tRNA to make amino acids and then proteins.
Vesicle • A vesicle is a bubble of liquid within a cell. • More technically, a vesicle is a small, intracellular, membrane-enclosed sac that stores or transports substances within a cell.
Rough Endoplasmic Reticulum (ER) • The endoplasmic reticulum (ER) is an eukaryotic organelle that forms an interconnected network of tubules, vesicles, and cisternae within cells. • Cisternae may also refer to flattened regions of the rough endoplasmic reticulum. • ER is like the plumbing.
Golgi Apparatus • The Golgi apparatus (also called the Golgi bodies, Golgi complex • The primary function of the Golgi apparatus is to process and package macromolecules, such as proteins and lipids, after their synthesis and before they make their way to their destination; it is particularly important in the processing of proteins for secretion. The Golgi apparatus forms a part of the cellular endomembrane system.
Cytoskeleton • The cytoskeleton (also CSK) is a cellular "scaffolding" or "skeleton" contained within the cytoplasm that is made out of protein. • The cytoskeleton is present in all cells. • It gives the cell form, support, and structure.
Cytoplasm • The cytoplasm is the part of a cell that is enclosed within the cell membrane.
Cell Membrane • The cell membrane (also called the plasma membrane) is one biological membrane separating the interior of a cell from the outside environment. • The cell membrane surrounds all cells and it is semi-permeable, controlling the movement of substances in and out of cells.
Smooth Endoplasmic Reticulum • The smooth endoplasmic reticulum (SER) has functions in several metabolic processes, including synthesis of lipids and steroids, metabolism of carbohydrates, regulation of calcium concentration, drug detoxification, attachment of receptors on cell membrane proteins, and steroid metabolism.
Mitochondria • A mitochondrion (plural mitochondria) is a membrane-enclosed organelle found in most eukaryotic cells. • Mitochondria are sometimes described as "cellular power plants" because they generate most of the cell's supply of (ATP) adenosine triphosphate, used as a source of the chemical energy. • In addition to supplying cellular energy, mitochondria are involved in a range of other processes, such as signaling, cellular differentiation, cell death, as well as the control of the cell cycle and cell growth.
Lysosomes • Lysosomes are the cells' garbage disposal system. • Lysosomes are spherical organelles that contain enzymes (acid hydrolases). • They break up food so it is easier to digest. • They are found in animal cells. • Lysosomes digest excess or worn-out organelles, food particles, and engulfed viruses or bacteria.
Plant Cell • Plant cells have the same organelles as animal cells with the addition of a cell wall and chloroplasts. • Cell walls give structure, connections and support. • Chloroplasts are what make plants green and produce food for the plant through photosynthesis.
Chloroplasts (only in Plant Cells) • Chloroplasts are organelles found in plant cells and other eukaryotic organisms that conduct photosynthesis. • Chloroplasts capture light energy to conserve free energy in the form of ATP through a complex set of processes called photosynthesis. • The word chloroplast is derived from the Greek words chloros, which means green, and plast, which means form or entity
Cell Wall (only in Plant Cells) • A cell wall is a tough, usually flexible but sometimes fairly rigid layer that surrounds some types of cells. • It is located outside the cell membrane and provides these cells with structural support and protection, and also acts as a filtering mechanism. • A major function of the cell wall is to act as a pressure vessel, preventing over-expansion when water enters the cell. • Animals and protozoa do not have cell walls.
Viruses • Viruses are not considered living things because they lack the ability to reproduce on their own. • They must attach to a host cell and use its DNA to reproduce. • Viruses look like space ships that have spikes and receptors sticking out.
DNA & RNA Know the structures and functions of nucleic acids in the mechanisms of genetics
Describe components of deoxyribonucleic acid (DNA), and illustrate how information for specifying the traits of an organism is carried in the DNA. • Explain replication, transcription, and translation using models of DNA and ribonucleic acid (RNA). • Identify and illustrate how changes in DNA cause mutations and evaluate the significance of these changes.
DNA - DEOXYRIBONUCLEIC ACID • DNA is sometimes called "the blueprint of life" because it contains the code, or instructions for building and organism and ensuring that organism functions correctly. • Just like a builder uses a blueprint to build a house, DNA is used as the blueprint, or plans, for the entire organism.
It is the chemical component of chromosomes, which are located in the nucleus of every cell. Segments of DNA (or bands on chromosomes) code for genes. • Gene - a segment of DNA that codes for a protein, which in turn codes for a trait (skin tone, eye color..etc), a gene is a segment of DNA. • The structure of DNA was established by James Watson, Francis Crick & Maurice Wilkins.
Basic Shape of DNA • The shape of the DNA molecule is a double-helix (like a twisted ladder). • The sides of the ladder are composed of alternating sugars (deoxyribose) and phosphates. • The rungs of the ladder are composed of nitrogen base pairs. • The rungs of the ladder can occur in any order (as long as the base-pair rule is followed) • For instance, a segment of DNA could be AATGACCAT - which would code for a different gene than a segment that read: GGGCCATAG. • All in all, there are billions of (nitrogen base, phosphate deoxyribose) groups in cells, which code for all the things an organism needs to function.
Parts: The rungs of the ladder, the base where you stand. • Nucleotides (3 part structure: nitrogen base, phosphate, deoxyribose) • Adenine, Thymine, Guanine, Cytosine or A, T, G, C • Bases pair in a specific way - called the Base-Pair Rule • Adenine pairs to Thymine: T & A • Guanine pairs to Cytosine: G & C
DNA REPLICATION • Replication is the process where DNA makes a copy of itself. • Why does DNA need to copy? Simple: Cells divide for an organism to grow or reproduce, every new cell needs a copy of the DNA or instructions to know how to be a cell. • DNA replicates right before a cell divides. • DNA replication is semi-conservative. That means that when it makes a copy, one half of the old strand is always kept in the new strand. This helps reduce the number of copy errors.
Replication • The way DNA makes exact copies. • It splits down the bases and makes exact copies of itself.
Transcription • When DNA untwists and separates and produces mRNA • RNA is formed by bonding to DNA
RNA Ribonucleic Acid • DNA remains in the nucleus, but in order for it to get its instructions translated into proteins, it must send its message to the ribosomes, where proteins are made. • The chemical used to carry this message is Messenger RNA mRNA
RNA is similar to DNA except: • 1. has one strand instead of two strands. • 2. has uracil instead of thymine • 3. has ribose instead of deoxyribose, a different sugar • mRNA has the job of taking the message from the DNA to the nucleus to the ribosomes.
Types of RNA Several types of RNA are synthesized in the nucleus of eukaryotic cells. Of particular interest are: • messenger RNA (mRNA). This will later be translated into a polypeptide. • transfer RNA (tRNA). RNA molecules that carry amino acids to the growing polypeptide. • There are some others that you do not need to know now.
Translation • Translation - Proteins are made from the message on the RNA DNA mRNA tRNA Translation Transcription
Translation • The mRNA goes to the ribozones and tRNA makes amino acids then proteins.
Proteins are Made • mRNA has the job of taking the message from the DNA to the nucleus to the ribosomes.
Gene Transcription: DNA → mRNA • DNA serves as the template for the synthesis of mRNA.