Cells Alive Overview of Cell Parts Cells Chapter 3
Cyt- cell Endo- in Hyper- above Hypo- below Inter- between Iso- equal Mit- thread Phag- eat Pino- drink -som - body Prefixes/Suffixes
What is in the cell? • Most of the cell space is Cytoplasm. • Cytosol: Gel like fluid where most of the cells chemical reactions take place. • Organelles: Mini cell organs that carry out specific job functions for the cell.
What is the biggest organelle? • The nucleus • The control center for the cell • Contains DNA • Contains the message that makes proteins • Proteins run the cell. • Contains the organelle= nucleolus • Nucleolus makes RNA that carries out DNA’s instructions.
What surrounds the nucleus? • The Phospholipid membrane • Two membranes. • Keeps DNA in • Only RNA can leave
What are the major organelles? • Ribosomes: rRNA. Where proteins are made. Usually on the rough ER. • Endoplasmic Reticulum: • rough ER close to the nucleus, where proteins are made • Smooth ER makes lipids. No rRNA present. • Golgi Apparatus: Ships proteins and lipids.
More organelles… • Lysosomes: SOS. Contain digestive enzymes. Kill invaders and worn out cell parts. • Mitochondria: Power house of the cell. Makes ATP (Body runs on ATP energy.) • Cytoskeleton: Skeleton of the cell. Shape • Centrioles: Move Chromosomes during cell division. • Microtubules: Basis for cilia and flagella
Ribosome Endoplasmic Reticulum Golgi Apparatus
Checkpoint • What is the functional difference between cilia and flagella? • What are the structural and functional differences between smooth and rough ER? • Which organelles contribute to synthesizing protein hormones and packaging them into secretory vesicles?
Fluid-Mosaic Model Cell Membrane
What surrounds the cell? • The Plasma Membrane. Made out of Phospholipids. • May have cilia or microvilli around the cell. • Microvilli are in the back of your throat (filter air) and in your intestine (absorb food)
Why is the plasma membrane selectively permeable? • Works as a barrier. Only allows certain things in or out of the cell. • Means of protection. • Cells that can not do this are dead or damaged.
Checkpoint • List the three main parts of the cell and explain their functions. • Why are membranes said to have selective permeability?
Membrane Transport Pg. 47-52
What are the two forms of cell transport? • Active Transport: uses energy (ATP) to move molecules against the concentration gradient or to move large things. • Passive Transport: uses NO energy to move molecules with the concentration gradient.
What types of Passive transport does the body use? • Diffusion: When molecules move from high to low or with the concentration gradient. • Perfume, food coloring, etc. all do this.
What types of Passive transport does the body use? • Facilitated Diffusion: Uses carrier proteins to move substances without energy with the concentration gradient. • Filtration: water and solutes are forced through a plasma membrane. Happens in the Kidneys.
Osmosis • Osmosis: a specialized form of diffusion which moves water from high to low across the plasma membrane.
Types of Solutions: Pg 50 • Isotonic Solution: Same tonicity inside and outside the cell. Cell stays the same size. • Hypertonic Solution: Higher tonicity outside the cell. Cell shrinks. • Hypotonic Solution: Lower tonicity outside the cell. Cell swells and “POPS”
What types of Active Transport do you use? • Solute Pumping: Require protein carriers and energy to move sugars, Amino Acids, and ions against the concentration gradient. (Sodium Potassium pump used in Nerve cells)
More Active Transport… • Bulk Transport: Substances too big to pass through the plasma membrane. • Exocytosis: Large things exit the cells • Endocytosis: Large things enter the cell • Phagocytosis: Cells that eat- white blood cell • Pinocytosis: Cells drink- intestine and kidneys
Checkpoint • How would having a fever affect body processes that involve diffusion? • If 0.9% NaCl is isotonic saline solution for red blood cells, would a 2% solution of NaCl cause the red blood cells to expand or shrink? • What is the key difference between active and passive transport? • In what ways are endocytosis and exocytosis similar and different?
How Proteins are Made Pgs. 58-62 Overview
What are the names of DNA? • Chromatin: Unwound DNA • Chromosomes: Tightly wound DNA
The Basic Process of Making Protein • DNA (In the Nucleus) is Transcribed into mRNA. (Transcription) • RNA brings the message to the Rough ER where its Translated into a protein. (Translation)
The Details: RNA(Ribonucleic Acid) • There are three types of RNA • mRNA (messenger RNA) • rRNA (Ribosomal RNA) • tRNA (Transfer RNA) • RNA is Single Stranded, sugar is RIBOSE • The Nitrogen bases for RNA are… • Adenine bonds to Uracil • Cytosine bonds to Guanine
The Story • DNA is stuck in the nucleus. • RNA is made in the nucleolus. • mRNA transcribes or re-writes DNA’s code in RNA and leaves the nucleus through nuclear pores. • mRNA brings the message to the ribosome also known as rRNA.
The fairy tale continues • Once mRNA is hooked onto the rRNA it needs the right amino acids to make a protein. • Remember 50 or more A.Acids make a Protein! • tRNA carries amino acids to the rRNA and hooks them onto the correct mRNA codon. • A codon is a three nucleotide sequence (AUG)
How does the story end? • When the stop codon is reached the Amino Acid chain falls off and rolls into a ball and becomes a protein. • mRNA goes back to the nucleus to be reused. • rRNA stays on the Endoplasmic Reticulum waiting for the next job. • tRNA picks up new Amino Acids for the next job.
Protein elongation and termination of protein synthesis during translation
Checkpoint • If the DNA template had the base sequence AGCT, what be the mRNA base sequence? • What is the difference between transcription and translation?
Chromosomes and Mitosis Pg. 62-65
Two different Cell Divisions • Meiosis- produces gametes or sex cells. New cells are different from the original cell. • Mitosis- produces new body cells-like your toes. New cells are identical to original cell.
Chromosomes: Tightly wound DNA. Resemble an X because two chromatids are held together.- Supercoiled. Centromere holds the chromosomes (Two sister Chromatids) together. Chromatid: A single tightly wound strand of DNA. DNA in all of its fine forms:
And last but not least… • DNA is your genetic information. In the shape of a double helix. The nucleotide pairs are: (Hydrogen bonds) • Adenine: Thymine • Cytosine: Guanine • DNA is broken into segments called genes which code for proteins. • Genes give you your physical characteristics.
Before Eukaryotic Cells Divide… • Its chromosomes are replicated. • Happens through the process of DNA Replication. DNA Replication: • DNA needs enzymes (protein) to copy or replicate itself. • Double helix unwinds using DNA Helicase. • DNA Helicase breaks the hydrogen bonds. • Where the DNA breaks apart is called the replication fork. DNA polymerase (another enzyme) adds nucleotides at this point.
How many Chromosomes do humans have? • Each somatic cell or body cell has two copies of 23 chromosomes. • One copy of the chromosomes (sex cells or gametes) have 23 chromosomes and are called haploid or n = 23. • Two copies of the chromosomes (somatic cells) have 2n = 46.