Biology Unit 4 Reading Packets

Mitochondrion are called power plants because they use energy from organic compounds to make ATP.

Identify the reason why mitochondria are called "power plants" of the cell.

Cristae

Inner membrane folds of the mitochondrion

Enzyme

Substance, usually a protein, that speeds up (catalyzes) a biochemical reaction

Flagellum

Tail-like structure that projects from the cell body of certain prokaryotic and eukaryotic cells; functions in helping the cell move

The mitochondria provides energy needed to power chemical reactions in the form of ATP.

What is the purpose of the mitochondria?

A ribosome does not have a membrane around it like the other organelles.

What is the significant difference between the structure of a ribosome and other organelles?

A basic light microscope

What scientific tool was used to first observe cells?

An electron microscope

What type of microscope would be best for studying the structures found inside of cells?

The Fluid Mosaic Model says the plasma membrane is in constant motion and changes in a Mosaic pattern.

Discuss the Fluid Mosaic Model.

Nuclear Envelope

Double membrane surrounding the nucleus of a cell

Chromosome

Strands of DNA wrapped around proteins

What type of molecule is common to all three parts of the cytoskeleton?

?

Ribsome

Organelle that makes proteins

Specimen

The object you are studying

Plasma Membrane

Thin coat of lipids that surrounds a cell, forms the physical boundary between the cells and its environment

Lipids and Proteins

What are the two main components of the cell membrane?

List two functions of the eukaryotic cytoskeleton.

1. Helps to maintain cell shape 2. Enables cell movement in some cells

List two roles of the cytoplasm.

1. Suspending cell organelles 2. Providing a site for many of the biochemical reactions of the cell

Cytoskeleton

A cellular "scaffolding" or "skeleton" that crisscrosses the cytoplasm

Tissue

A group of connected cells that have a similar function within an organism

Organ System

A group of organs that act together to carry out complex related functions, each organ focuses on a part of the task

Organ

A group of tissues that has a specific function or group of functions

Vacuoles

A membrane bound space within the cell used for storage.

Membrane Protein

A protein molecule that is attached to, or associated with, the membrane of a cell or an organelle

No, the cell theory says that all cells come from other cells so molecules cannot make a cell.

According to the cell theory, can we create a new cell in laboratory by putting different molecules together? Why or why not?

Cytoplasm

All cellular material inside the plasma membrane, other than the nucleus; made up of cytosol and other cell structures

Semipermeable

Allowing only certain materials to pass through; characteristic of the cell membrane

Cell Membrane

Another name for plasma membrane

Yes

Are all cells surrounded by a membrane?

Nucleolus

Area within the nucleus where ribosomes are made

Cilia

Brush-like plasma membrane extension

Nucleus

Cell structure that contains the genetic material, DNA

Eukaryotic Cell

Cell that contains a nucleus and membrane-bound organelles

Prokaryotic Cell

Cell without a nucleus or membrane-bound organelles

Chromosomes

Composed of DNA and proteins in eukaryotic cells

Cytoplasm

Consist of everything inside the plasma membrane, excluding the nucleus

What is the difference between cytoplasm and cytosol?

Cytosol is the watery, gel-like material in cells. Cytoplasm is the cytosol and the organelles of the cell.

Fluid Mosaic Model

Depicts the biological nature of the plasma membrane

The plasma membrane is composed of phospholipids, which have a hydrophilic head and two hydrophobic tails.

Describe the composition of the plasma membrane.

Cells > Tissue > Organ > Organ System > Organism

Describe the levels of organization of an organism.

Phospholipids have hydrophilic heads which form the surface and interior of the membrane, the hydrophobic tails face each other.

Describe the orientation of the phospholipid molecule in the cell membrane.

The cholesterol strengthens the plasma membrane by reducing lipid fluidity.

Describe the role of cholesterol in the cell membrane.

The plasma membrane forms a barrier between the inside of the cell and the environment outside of the cell.

Describe the role of the plasma membrane.

Intermediate Filaments

Differ in make up from one cell type to another and organize the inside cell structure by holding organelles and providing strength

ATP (adenosine triphosphate)

Energy-carrying molecule that cells use to power their metabolic processes; energy-currency of the cell

Cytoplasm

Entire contents of the cell inside the plasma membrane, excluding the nucleus

Nucleus

Eukaryotic cell structure that contains the genetic material, DNA.

Hydrophobic molecules pass through easily because they hate water like the inside of the membrane. Hydrophilic molecules cannot pass through because they love water like the outside of the membrane.

Explain why hydrophobic molecules can easily cross the plasma membrane, while hydrophilic molecules cannot.

Matrix

Fluid-filled inside of the mitochondrion

Cytoskeleton

Framework of the cell that lends support and defines its shape

Microtubules

Hollow cylinders and are the thickest of the cytoskeleton structures

The rough ER has ribosomes attached and the smooth ER does not. Another difference is the rough ER makes proteins and the smooth ER makes lipids and carbohydrates.

How is the smooth ER different from the rough ER?

Liver cells contain between ten to twenty thousand ribosomes.

How many ribosomes are in a typical liver cell?

Cytosol is 65% if the cell's total volume.

How much cytosol is in a cell, compared to the total cell volume?

Cytosol

Jelly-like substance in which the contents of the cell are suspended

Plasma Membrane

Lipid barrier that surrounds the cell; also known as cell membrane

Phospholipid

Lipid molecule with a hydrophilic head and two hydrophobic tails; makes up the cell membrane

Plasma Membrane

Lipid-barrier that surrounds the cell; known as cell membrane

Microfilaments

Made of two thin actin chains, twisted around one another

Vacuole

Membrane-bound space within the cell used for storage of water, wastes, and nutrients

Name the three main parts of the cytoskeleton.

Microtubules, Intermediate Filaments, and Microfilaments

DNA

Nucleic acid in cells, contains genetic instructions to make proteins

Deoxyribonucleic Acid (DNA)

Nucleic acid that is the genetic material of all organisms

Mitochondria

Organelle in eukaryotic cells that makes energy available to the cell in the form of ATP molecules

Ribosome

Organelle in which proteins are made (protein synthesis)

Ribosome

Organelle inside all cells where proteins are made; site of protein synthesis

Mitochondrion

Organelle of the cell in which energy is generated

Lysosome

Organelle of the cell that breaks down and recycles old molecules

Chloroplast

Organelle that carries out photosynthesis in plants

Endoplasmic Reticulum

Organelle that is the site of lipid synthesis and protein modification

Golgi Apparatus

Organelle that processes and packages proteins

Prokaryote

Organism that lacks a nucleus, ex: bacteria

Eukaryote

Organism with cells containing a nucleus and membrane-bound organelles

Integral Membrane Proteins

Permanently embedded within the plasma membrane, functions include channeling or transporting molecules across the membrane

Phospholipid Bilayer

Phospholipids in the plasma membrane arranged in two layers

Electron Microscope

Powerful microscope that passes a beam of electrons through the specimen

Photosynthesis

Process by which specific organisms use the sun's energy to make their own food from carbon dioxide and water; process that converts the energy of the sun, or solar energy, into carbohydrates, a type of chemical energy

Translation

Process in which genetic instructions in mRNA are read to synthesize a protein

Protein Synthesis

Process of ribosomes making proteins

Actin

Protein that forms microfilaments

Tubulin

Protein that forms microtubules

Ribozymes

RNA molecules that catalyze chemical reactions; RNA molecules with enzymatic activity

Vesicle

Small membrane enclosed sac; transports proteins around a cell or out of a cell.

Plastid

Small membrane-bound organelle of plant cells with varying functions

Cell Theory

States that all organisms are composed of cells, cells are alive and the basic living unit of organization in all organisms, and all cells come from other cells

Organelle

Structure within the cell that has a specific role

Organelle

Structure within the cell that has a specific role.

Ribosomes

Structures in the cytoplasm where proteins are made

Peripheral Membrane Proteins

Temporarily associated with the membrane, involved with cell signaling, ion channels, and transmembrane receptors

What is the purpose of the Golgi?

The Golgi receives proteins from the rough ER and then puts them in vesicles and sends them to where they are needed.

Semipermeability

The ability to allow only certain molecules in or out of the cell (also known as selective permeability)

Cytoplasm

The entire contents of the cell inside the plasma membrane, excluding the nucleus

Cell

The smallest unit of an organism that is still considered living

Cell Wall

Tough outer layer of plant cells that helps support and protect the cell; also found around bacterial cells

Gene

Unit of DNA that contains code for the creation of one protein

Hydrophobic

Water-hating

Hydrophilic

Water-loving

Cytosol

Watery substance in cytoplasm

Cytosol

Watery, gel-like material in cells

Flagella and cilia are plasma membrane extensions that are whip or brush like.

What are flagella and cilia?

Lysosomes are membrane enclosed vesicles formed in the Golgi. They include enzymes that digest and destroy large molecules outside the Golgi.

What are lysosomes? What are their function? Where do they occur?

Organelles are a structure within the cell that have a specific role.

What are organelles?

Possible functions are photosynthesis, storing starch or oil, and giving plants their color.

What are some possible functions for plastids?

The proteins have functions which include transports, identification, attachment, metabolism, and signal transduction.

What are the functions of proteins associated with the cell membrane?

The ER helps transportation of several things in the cell. Ribosomes give rough ER the "rough" appearance.

What are the functions of the endoplasmic reticulum? What gives the ER its "rough appearance?

The proteins are either permanently or temporarily attached to the plasma membrane.

What are the main differences between the types of proteins associated with the plasma membrane?

Ribosomes are found in large numbers in the cell and can be found on the rough ER or just in the cell. The ribosomes make proteins needed for the cell or outside of the cell.

What are the most abundant organelles in a cell? Where do they occur? What is there function?

Microtubules, microfilaments, and intermediate fibers.

What are the primary types of protein filaments that make up the cytoskeleton?

1. All organisms are composed of cells 2. Cells are alive and the basic living units of organization in all organism 3. All cells come from other cells

What are the three main parts of the cell theory?

Ribosomes are mainly found on the endoplasmic reticulum and the nuclear envelope.

What are the two general locations ribosomes are located in the cell?

Cell Wall, Large Vacuole, Chloroplasts

What are three structures that are found in plant cells but not in animal cells?

All cells have a plasma membrane, ribosomes, cytoplasm, and DNA.

What do all cells have in common?

A lipid with glycerol at the structural core and is part of the plasma membrane.

What is a glycolipid?

Peroxisomes protect the cell from its own production of toxic hydrogen peroxide. They are organelles that occur in the cell's cytoplasm.

What is a peroxisome? What is it's function? Where does it occur?

Secretory vesicles are transported to the cell surface to release cell secretions. They are at the Golgi.

What is a secretory vesicle? Where are they made? What is their function?

Chromatin is the DNA wrapped loosely around proteins in the nucleus. The chromatin is made up of nitrogen, DNA, and proteins.

What is chromatin? What molecules make up chromatin?

The nucleus holds our DNA and the nucleolus.

What is contained in the nucleus of a cell?

Cytosol is the watery substance that contains other molecules in the cell. Cytoplasm is the cytosol and all the organelles in the cell except the nucleus.

What is cytosol? How does this differ from cytoplasm?

Cytoplasm includes 70-90% water and contains all cellular contents except the nucleus. Cytosol is a mixture of cytoskeleton filaments, dissolved organic and inorganic molecules, and water.

What is included in a cell's cytoplasm? What is in the cytosol?

Permeable means anything can cross a barrier, the plasma membrane is semipermeable because only some things can cross the barrier.

What is meant by the description of the plasma membrane as "semipermeable"?

The Golgi looks like flattened sacs stacked on top of each other. The Golgi sorts, processes, packages, and delivers proteins or lipids in the cell

What is the appearance of the Golgi apparatus? What is the function of the Golgi apparatus?

Cytosol is composed of water and molecules like enzymes.

What is the cytosol composed of?

A cell is the basic living unit and a tissue is a group of cells working together.

What is the difference between a cell and a tissue?

Cytosol is the jelly-like substance where the contents of the cell are. Cytoplasm is all the contents of the cell except the nucleus.

What is the difference between the cytosol and the cytoplasm?

Ribosomes make proteins.

What is the function of a ribosome?

Mitochondria generate energy to keep the cell alive. The mitochondria have two membranes. Cells could have one to thousands of mitochondria. The number of mitochondria depend on the amount of energy needed.

What is the function of mitochondria? What kind of membrane does a mitochondrion have? Do all cells have the same number of mitochondria? How can this situation be explained?

The nucleolus makes ribosomes.

What is the function of the nucleolus?

Membrane proteins determine what enters and leaves the cell.

What is the major role of many Membrane Proteins?

Ribosomes are made in the nucleolus. They are made of rRNA and proteins.

Where are ribosomes made? What are ribosomes made from?

Eukaryotic cells have membrane-bound organelles. Plasmids are not membrane-bound organelles.

Where do you find membrane-bound organelles? Are plasmids membrane-bound organelles?

Flagella

Whip-like plasma membrane extension

Mitochondria can grow and self-replicate within the cell. Each one has its own ribosomes and DNA.

Why are mitochondria said to be semi-autonomous in a cell? Be specific and explain your answer as fully as possible.

There are many types of multicellular organisms at each level of organization so it is easier to keep everything organized.

Why are multicellular organisms highly organized?

Phospholipids are hydrophilic and hydrophobic so that makes them dual-natured meaning amphipathic.

Why are phospholipids considered an amphipathic molecule?

Cell membranes are described as fluid mosaics because they have many different molecules and they move a lot.

Why is the structure of the cell membrane described as "fluid mosaic"?