Unit 2, Lesson 1-The Cell (K12 notes)

• The cell is the most basic structure that exhibits the characteristics of life• The cell is considered the fundamental unit of life• Cell Theory consists of 3 parts:

1. All known living things are made up of one or more cells.2. The smallest living things are single cells, and cells are the

functional units of multicellular organisms.3. All cells come from other cells.

Why are they important-no cells…no life!

The Cell

Major parts of a cellNucleus-a cell organelle that is essential to cell functions including reproduction, contains the cell´s chromosomes, and is enclosed by a membrane Cytoplasm-the substance inside a cell, prokaryotic or eukaryotic, including organelles, but not including the nucleus of a eukaryotic cell Organelles- perform the different functions the cell needs to meet the challenges of life: getting and using energy, reproducing, and maintaining structure.Plasma Membrane-the structure that forms the surface of a cell separating its contents from the outside world

Types of Cells

• 2 types of cells: prokaryotic cells• a type of cell without a membrane-bound nucleus and without

membrane-bound organelles, considered by scientists to be a more primitive type of cell than the more complex eukaryotic cells

• eukaryotic cells• a type of cell that has a membrane-bound nucleus and

membrane-bound organelles

How are they the same or different?

Unit 2, Lesson 2-Differing Cells (K12 notes)• Prokaryotes• Bacteria are the smallest of the single-celled organisms.• are relatively simple compared with all other types of cells and

organisms.• usually have one of three shapes: spherical, elongated (rod-

shaped), or spiral.• surrounded by a plasma membrane that contains the cytoplasm

and separates the inside of the cell from its external environment. • Many also have cell walls—relatively rigid structures outside their

plasma membranes.

Prokaryotic Cell

• Eukaryotes• cells found in plants and animals• larger, more complex, and more diverse than prokaryotes• contain a nucleus and organelles that are surrounded by

membranes• genetic material is in the membrane-bound nucleus• cytoplasm membrane-bound organelles, such as mitochondria• cells that can perform photosynthesis, such as plant cells, also

have chloroplasts

Eukaryotic Cell

Plant Animal

Lesson 3-Cell Organelles

Prokaryotic Cell• membrane-bound organelles. • instead of a membrane-bound

nucleus, genetic material is found in a region of the cell called the nucleoid• Sometimes have small circles of

genetic material in the cytoplasm-called plasmids

Eukaryotic Cell• have membrane-bound organelles• Nucleus-the director of the cell…

contains the genetic material of the cell and is surrounded by a double-layered nuclear membrane• nuclear membrane is connected to a

series of other membranes called the endomembrane system (like our bloodstream)• form sacs, tubes, layers, and folds

Energy

• After sugars are broken down in the cytoplasm of the cell they head to the• mitochondria, the power plants of the cell, convert these sugars into

a more usable form of energy• This conversion process is called cellular respiration. • The chemical reactions of cellular respiration occur on the folds of

membranes that fill the mitochondria.

Protein

• The ribosomes are the protein factories of the cells.

• They use the genetic instructions from the nucleus to assemble the proteins of the cell as well as other proteins the body needs.

• Both prokaryotes and eukaryotes have ribosomes.

Remember that the genetic material of: prokaryotes … nucleoid eukaryotes…membrane-bound nucleus

Movement

• Some cells can move around using specialized structures• Flagella are long, whip-like structures found on the surface of some

prokaryotic and eukaryotic cells…motion propels the cell through fluids. • Cilia are shorter, hair-like structures found on some eukaryotic cells.

Cells that have cilia usually have a lot of them. Even if the cell doesn’t move around, cilia can move fluid over the surface of the cells

Structure

• A cell has its cytoskeleton—a system of fibers and tubes that gives the cell support and structure (like our skeleton). • The cytoskeleton is made of proteins.

FYI

• Plant cells also have specialized organelles, the most important of which are chloroplasts. Photosynthesis occurs in chloroplasts.

Lesson 4-Looking at Cells

A Little History aboutMicroscopes

Lesson 6-DNA to RNA to ProteinsHow does a cell know what to do?

• Inside each cell is DNA (a nucleic acid) molecule that carries information and instructions for the cell.

• These instructions tell the cell how to make the proteins it needs to perform its functions.

What do proteins do?

• Proteins are the bodies workers.• Just about every biochemical reaction that takes place in your cells is

made possible by proteins.• Examples of some proteins: insulin, hemoglobin, rhodopsin etc

• Proteins are assembled in the cytoplasm by ribosomes.• **Remember: DNA, which has all the genetic information needed to

make these proteins, is located in the nucleus of a eukaryotic cell (or in the nucleoid of a prokaryotic cell)

Lesson 7-Plant & Animal Cells

How can you tell the difference between plants and animals?• Look at the cells.

• How are they similar:• First, both are living things, which means that they are made up of one or more cells.• They are classified as eukaryotes because their cells have a membrane-bound nucleus and

organelles.

• How are they different:• Plant cells don’t have flagella (long structures on surface of cell to help them move), cilia

(hair-like structures on surface) or known lysosomes.(organelle found in animal cells)

Differences continued

• Plant cells have a large central vacuole, a fluid-filled sac that is part of the endomembrane system. The central vacuole helps control the water content of the cell and also stores material.• Plant cells have chloroplasts where they make their own food by converting light

energy to chemical energy by photosynthesis.

Lesson 7 Questions-

• Name one similarity among plant and animal cells• Name one difference between plant and animal cells

Lesson 8-Cells & Energy

Thousands of chemical reactions are going on in each cell, and those chemical reactions require energy!

In Animals:• Mitochondria and other organelles inside cells break down food into

molecules that these cells can use.• Cells use glucose (, which is broken down in the cytoplasm (then the

products of that process are transported into the mitochondria. • Cells also use oxygen from the lungs.• This process called cellular respiration uses glucose + O2=>CO2 + H2O,

this energy is stored in the form of ATP(adenosine triphosphate)

• In Plants:• Plants make energy by photosynthesis.• During photosynthesis, plant cells use the energy from light to convert carbon

dioxide (CO2) and water (H2O) into glucose and oxygen (O2).• Like in animal cells, the mitochondria in plant cells convert the energy from

glucose into the chemical bonds of ATP

Single-Celled Organisms Need Energy too• Single-celled organisms obtain energy by making their own

food or through decomposition. (process of breaking down organic material)

Lesson 8 Questions

•What is the process by which plants make energy? •What is the process by which animals make energy?

(Let’s see how well you can spell them! LOL)

Lesson 9-Diffusion &

Osmosis

Cell Membrane

• a boundary between the cell and everything that surrounds it, a thin structure that forms a boundary between the inside and outside of the cell•helps keep all the contents of the cell from floating

away• regulates what goes into and out of the cell***Think tea bag.!

Diffusion

• overall movement of molecules from a region of higher concentration to a region of lower concentration by their random movements, tending to reduce the difference in concentration (the amount of something in a given volume) between the two regions• movement of molecules tend to even out their concentration throughout the

solution, from regions of high concentration to regions of low concentration• does not require any addition of energy to the molecules

Osmosis

• Movement, or diffusion of water across a selectively permeable membrane from an area of high water concentration to an area of low water concentration • selectively permeable to the water more than to other molecules• **Think sponge**

Lesson 10-Cell Division

What do cells need and do?

• Food• Water• Communication• Waste management• Building materials• Require space for their essential functions• Usually grow larger• and more

 So, what do cells do when they get too big?They Divide!• Cell Theory states that all new cells come from other cells. • One-celled organisms reproduce by dividing themselves into two

parts.• Multicellular organisms increase the number of their cells through

cell division. • One cell divides and becomes two new cells. Cell division helps

the organism grow and repair damaged tissues. Old cells are replaced with new ones.

• A Cell that divides is called a parent cell.• The two new cells that result from this division are called

daughter cells. That doesn’t mean they are all female. They’re called daughter cells because they come from the parent cell.• Each daughter cell gets a full set of chromosomes from

the parent.

**Chromosome-threadlike structures made of protein and DNA that contain the instructions for building, maintaining, and operating the cell.

Stages of the Cell Cycle

• Before mitosis, the parent cell grows and makes a copy of the genetic material in the nucleus.• During mitosis, the genetic material is divided between the daughter

cells.• During cytokinesis, the cytoplasm (the substance in cell between

nucleus and membrane) is divided between the daughter cells

Meiosis Mitosis

How does the DNA turn into the actions of proteins and how does it get from the nucleus to the ribosome? The answer is RNA, ribonucleic acid. DNA is a kind of code. Everyone has their own code that is represented in every cell of their body.RNA can then transport that copy of the DNA information to the ribosomes. At the ribosome, the unique sequence of RNA is decoded into a unique sequence of amino acids to make a protein.

Unit 2, Lesson 11- MitosisMitosis is the first phase in the 2 phase cell division.

• During mitosis, the two copies of the parent cell's DNA are divided between new, or “daughter” cells.• Then the sister chromatids separate and move to opposite ends of the

cell. • By the end of mitosis, two full sets of chromosomes are grouped

together.***Scientists divide mitosis into four stages: prophase, metaphase, anaphase, and telophase.***

Vocabulary:

• Chromatids-two copies of a duplicated chromosome that will eventually end up in separate cells

• Centromere-place where two sister chromatids join in a chromosome before it divides during mitosis or meiosis

• Prophase-1st phase of mitosis, in which the chromosomes coil and become more compact

• Metaphase-second phase of mitosis, in which the chromosomes arrange in a plane at the middle of the cell

• Anaphase-third phase of mitosis, in which the chromosomes split and move apart• Telophase-fourth and final stage of mitosis, in which the chromosomes reach two

sides of a cell and are incorporated into two new nuclei

Prophase (Stage 1)

• 1. The chromosomes coil up tightly. This makes them more compact so that they can move easily and avoid breaking.• 2. The membrane surrounding

the nucleus breaks down, freeing the chromosomes.• 3. A system of fibers called the

spindle starts to form.

Metaphase (Stage 2)

• Metaphase begins as the chromosomes spread out across the center line of the cell.• Each pair of sister chromatids is

now attached to a spindle fiber by its centromere.

Anaphase (Stage 3)

• The spindle fibers start to pull away from the center of the cell. The sister chromatids are pulled apart and the spindle acts like a conveyor belt carrying them to opposite ends of the cell

Telophase (Stage 4)

• The sister chromatids have moved to opposite ends of the cell. • The spindle is no longer needed,

and it breaks down. • Nuclear membranes form around

each set of chromosomes to form two separate nuclei. • Mitosis is complete.• But even though there are two

nuclei, there is still only one cell.

Cytokinesis-2nd phase of Cell Division• For cell division to be complete,

the cytoplasm must divide.• In cells without a cell wall, the

center of the cell pinches inward until the parent cell is pulled apart into two cells.

• In cells with cell walls, a new piece of wall forms between the two sets of chromosomes and separates the cytoplasm. In either case, the two sets of chromosomes now reside in separate daughter cells.

Before taking the Unit 2 Assessment-•Make sure you have all of Unit 2 notes- if not, send me a Kmail and I will send them to you!•Review ALL of your notes from every lesson and all worksheets•Watch all video clips- links are in your notes•Complete the Unit Review lesson

More resources!

Bill Nye the Science Guy video on Cellshttps://www.youtube.com/watch?v=ZG2Gs_oaSog

www.thehappyscientist.comUsername-LVSPassword-LVS

What is DNA? Video clip-https://www.youtube.com/watch?v=zwibgNGe4aYwatch this- it explains the process very well!Cell Divisionhttp://www.neok12.com/php/watch.php?v=zX645478027c03150f647502&t=Cell-Division