Warm Up You will turn this in! On the front of your paper, draw what you think a cell looks like. Label it if you would like. On the back of your paper, write anything and everything that you know about cells (even if you think it may be wrong).

Warm Up Write the equation for aerobic cellular respiration. Explain what that equation means. Write the equation for photosynthesis

The Cell: Structures and their Functions

The Cell The smallest, basic structural unit of all living organisms Different types based on what the organism is: Bacteria: Prokaryotic cell Animal: Eukaryotic cell, animal cell Plant: Eukaryotic cell, plant cell

Prokaryotic vs. Eukaryotic

Prokaryotic and Eukaryotic Cells Characteristic Prokaryotic Cell Eukaryotic Cell Size Nucleus Membrane Bound Organelles (MBO) Cell Wall Plasma Membrane Chromosome Arrangement (DNA) Small Large True nucleus, consisting of nuclear membrane & nucleoli Completely absent Absent (but has ribosomes) present When present, chemically simple Usually present; chemically complex Present, and chemically simple Present; chemically complex Complex chromosomes Simple chromosomes (PLASMID)

Scientists believe the prokaryotic cell evolved first because it is simpler than the eukaryotic cell. Example of a prokaryotic cell: bacteria Example of a eukaryotic cell: plant, animal, and fungi.

Plant vs. Animal Cell PLANT All organelles in animal cell PLUS Cell wall Chloroplast ANIMAL Nucleus Ribosome Mitochondria Vacuole Plasma Membrane

Animal Cell

Plant Cell

Cell specialization: Hierarchy of cells- Cells form a certain hierarchy: (From smallest to largest with example) Organelle – mitochondria, nucleus Cell – skin cell, liver cell Tissue – muscles Organ – liver, stomach, brain Organ system – digestive, endocrine Body – humans, fish, dogs, etc

Cell Types Not all cells are shaped the same. They have different shapes to accommodate their jobs.

Cell communication Cells recognize one another Chemical signals may be released by one cell to influence the activity of another cell. Ex. a nerve cell can send a message to a muscle cell or to another nerve cell in response to something hot.

Homeostasis in the cell Internal stability/equilibrium/balance It is controlled by an organelle called the plasma membrane (only allows some substances to pass.) The following needs to be maintained: pH Temperature Salinity Blood Glucose levels

How pH is maintained Through a buffer system Buffer: a solution that has a stable pH When you add an acid to a buffer solution the buffer will neutralize it (cause it to become more basic) When you add a base to a buffer solution the buffer will neutralize it (cause it to become more acidic)

How temperature is maintained If cell needs to cool down: plasma membrane becomes more fluid to release heat If cell needs to heat up: plasma membrane becomes more rigid to keep internal heat from escaping

How salinity is maintained Through plasma membrane and a natural process called diffusion (will discuss more in depth later)

How blood glucose is maintained If blood glucose is low: body releases hormone (glucagon) to cause levels to rise If blood glucose is high: body releases hormone (Insulin) to cause levels to lower People with diabetes do not produce insulin so have trouble regulating blood glucose levels.

Warm Up How is pH maintained in a cell? Give one difference between a prokaryotic cell and a eukaryotic cell. What 2 organelles are present in a plant cell but not present in an animal cell? What type of cell (pro or eu) are plant and animal cells?

How a cell functions: ORGANELLES As a human, we wouldn’t be able to function without our organs (stomach, liver, kidney, pancreas, etc, etc, etc) A cell can’t function without its “organs” either. BUT a cells “organs” are called ORGANELLES Today we will review the most important organelles in a cell and their function

Organelle: Mitochondria The “POWERHOUSE” of the cell Function: provide energy to the cell (cellular respiration) How? Takes the food we eat and turns it into the energy source (known as ATP)

Organelle: Mitochondria How structure enhances its function: The organelle has two membranes (one protects the organelle, the other allows it to complete its task) The “folds” in the inner membrane (called cristae) increase the surface area inside the small organelle so that it can do as much work as possible!

Cell Part: Ribosome Function: makes proteins through a process called protein synthesis 2 parts: large subunit and small subunit How structure enhances its function: 2 subunits allow for protein synthesis (a very tedious/complex process) to be more simplistic More later…

Organelle: Nucleus The “CONTROL CENTER” of the cell Function: contains all genetic information (in the form of DNA) in the cell

Organelle: Nucleus How structure enhances its function: DNA can NEVER leave the nucleus but we need the DNA code to make proteins The nucleus contains “pores” or holes on the outer membrane A material called “mRNA” that contains the DNA code can leave through the pores to take the DNA message to the ribosomes so that proteins can be made.

Organelle: Vacuole The “GARBAGE DISPOSAL” of the cell Function: takes up waste or excess materials from the cell (cellular digestion)

Organelle: Vacuole How structure enhances its function Vacuoles in animal cells are small and there may be multiple. In plant cells there is only one vacuole and it is extremely large Why? Plants can’t control the weather. If they get too much water, the vacuole takes it in and their volume will increase. If there is too little water, the vacuole will shrink and the plant will “droop”. Vacuoles help with plant rigidity

Cell Part: Plasma Membrane The “GATEKEEPER” of the cell Function: monitor what materials are going into and coming out of the cell (cellular transport) How? By use of phospholipid bilayer and proteins

Cell Part: Plasma Membrane How structure enhances its function: Small molecules coming into or out of the cell can pass through the spaces between the phospholipids. Larger/bulky molecules coming into or out of the cell can pass through with help from the embedded proteins More later…

Cell Part: Cell Wall ONLY FOUND IN PLANT CELLS!!!!! Function: gives plant cell structure and support Made of cellulose...a carbohydrate

Organelle: Chloroplast ONLY FOUND IN PLANT CELLS!!!!!! Function: Photosynthesis (a process that creates food in the form of sugars for the plant and creates Oxygen that is released into the atmosphere for animals to use)

Warm Up What organelle is responsible for cellular respiration? What organelle is responsible for cellular transport? What is the purpose of photosynthesis? Where does protein synthesis occur? Why does the nucleus have pores?

Completed by the plasma membrane TRANSPORT Completed by the plasma membrane

Plasma Membrane Plasma Membrane: -Function: allows chemical substances to enter and leave the cell. -Structure: phospholipid bilayer and proteins

Why a phospholipid bilayer? Phospholipids are both hydrophilic and hydrophobic. Heads are hydrophilic, tails are hydrophobic Bilayer forms because the tails are trying to get away from the water

Why proteins? Proteins help move larger/bulkier molecules into and out of the cell. They are considered FACILITATORS

Types of Transport: 1. Passive Transport- cell does not use energy (ATP) to move substances across the plasma membrane. 3 TYPES OF PASSIVE TRANSPORT: -Diffusion -Facilitated Diffusion -Osmosis

Diffusion and Osmosis Diffusion: The net movement of particles from areas of high concentration to areas of low concentration Osmosis: The same as diffusion but with water ONLY

Facilitated Diffusion Proteins provide a pathway for substances to pass through the membrane

2. Active transport- the cell uses energy (ATP) to move substances across the plasma membrane against the concentration gradient through a protein

Passive Transport Active Transport Follows concentration gradient (high to low) Goes against concentration gradient (low to high). Requires ATP (energy) Materials are going towards equilibrium Materials are not going towards equilibrium Examples: Diffusion, osmosis, facilitated diffusion Examples: excretion of waste products, sodium/potassium pump

Active transport example: Sodium/Potassium pump Sodium is SALT. You don’t want a lot of salt in your body. You want potassium! Our cells actively take in 2 molecules of potassium for every 3 molecules of salt (sodium) that it pumps out. Requires energy (ATP) to complete this process. Necessary because it keeps us healthy!

Video Review https://www.youtube.com/watch?v=kfy92hdaAH0

Warm Up What is the monomer of carbohydrates? Lipids? Proteins? Nucleic acids? What are the use(s) of carbohydrates? Lipids? Proteins? Nucleic acids? What type of organic molecule is cellulose? What type of organic molecule is insulin?