Cells and Tissues

What is it that makes you you?

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 names of DNA?

• Chromatin: Unwound DNA

• Chromosomes: Tightly wound DNA

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). Pg.389 +419

What is in the cell?

• Most of the cell is full of Cytoplasm.– Cytoplasm: 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.

Cells Alive

Overview of Cell Parts

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.

Membrane Transport

Pg. 46

What kinds of fluids pass through the cell membrane?

• Solution: homogeneous mixture of two or more things– Solvent: Bigger word, bigger thing– Solute: Smaller word, smaller thing

• Intracellular fluid: fluid in the cell that contains gasses, nutrients, salts, & water

• Interstitial fluid: bathes the outside of our cells.

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.

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.

• Osmosis: a specialized form of diffusion which moves water from high to low across the plasma membrane.

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.

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

Types of Solutions: Pg 60

• 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”

Chromosomes and Mitosis

Pg. 63

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:

Homologous Chromosomes

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.

It DNA the final say?

• Epigenetics may play a role.

Epigenetic EffectOn DNA

EpigeneticMovie

Before Eukaryotic Cells Divide…

• Its chromosomes are replicated.• Happens through the process of DNA

Replication. DNA Replication pg.68• 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.

There are two types of Chromosomes.

• Autosomal Chromosomes: or autosomes are not sex chromosomes.

• Sex Chromosomes: determine the sex of the individual. The male of the species determines the sex of the offspring. Women only have one X chromosome. Males have an X or a Y.

• XX is a girl• XY is a boy

Karyotypes: Pictures of your DNA.

• Why do we take pictures? To find mistakes

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The 5 stages of the Cell Cycle 6-2

• G1: Cell Growth and Metabolism

• S: DNA is copied

• G2: Cell prepares for division.

• Mitosis: Nucleus divides, cell parts separate.

• Cytokinesis: Cytoplasm divides

When control of the Cell cycle is lost: Cancer is the outcome.

• Cancer: uncontrolled cell division or death.

• Read pg 127: Normal cells become cancerous.

Hit the Cancer BiologyDocumentary Link

Mitosis The Basic Steps:6:3 • Prophase: DNA forms chromosomes.

Nuclear envelope disappears. In Animals spindle fibers form.

• Metaphase: Chromosomes move to the center of the cell- pulled by spindle fibers.

• Anaphase: Chromosomes are separated into chromatids. Spindles shorten pulling chromatids to opposite ends of the cell.

• Telophase: Nucleus reforms. Chromatids turn back into Chromatin. Spindles disappear. The Jazzy

Version ofMitosis

After Mitosis

• Cytokinesis: Cytoplasm divides in half.

• Animals: The plasma membrane pinches in half= Furrow.

• Plants: A cell wall grows between the two new cells. Cell Plate.

Cell Cycle Movie/Game

Meiosis

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Meiosis: The making of gametes

• One cell eventually creates four cells

• Each cell is different from the parent cell

• Haploid

• Meiosis goes through cell division twice

The Stages of Meiosis

• Prophase 1: Chromosomes are made and the nucleus membrane disappears.

• Homologous Chromosomes pair and attach by centromeres.

• Crossing-over occurs. Cross over is the process of homologous chromosomes breaking off and exchanging parts. – This process is responsible for making you

unique!

Meiosis Continued

• Metaphase 1 Homologous chromosomes are pulled by spindle fibers to the middle of the cell. (Two pair of homologous chromosomes are together.)

• Anaphase 1• Pair of Homologous

chromosomes separate. Spindle fibers attach to a centromere to guide homologous chromosomes to opposite ends of the cell.

Meiosis Continued

• Telophase 1

• Homologous chromosomes are at opposite ends of the cell. Cytokinesis occurs.

• Two cells have been made. We need 4.

• Here ends the first cell division.

• Ready for part two?

Meiosis- Part 2

• Prophase II

• New spindle fibers form around homologous chromosomes. Nucleus disappears.

• Metaphase II

• Chromosomes line up in the middle (or equator) of the cell.

And finally…Meiosis ends

• Anaphase II

• The spindle fibers pull the homologous chromosomes apart. Chromatids move to opposite ends of the cell.

• Telophase II• A new nucleus is

formed. Spindle fibers dissolve.

• Cytokinesis occurs.• Four cells, genetically

different from the parent cell have been made.

Why does Meiosis create genetic variation?

• Crossing over. Mixes up the traits on each chromosome.

• Independent assortment. You have 46 chromatids. ½ go to each new cell in Meiosis 1 and again in Meiosis II. No one knows which chromatids will go to which cell.

• Random Fertilization. Which egg and which sperm will meet? = a greater genetic variability.

Making Gametes: Different for different sexes.

• Sperm Formation• Spermatogenesis• One diploid germ cell

makes four haploid sperm cells.

• Occurs in the testis throughout the males adult life

• Egg formation: Ovum• Oogenesis

• One diploid germ cell makes one egg and three polar bodies.

• Egg must provide the food for the zygote (fertilized egg)

• Made in ovaries, most before birthThird Link

Comparison ofOOGENESIS

&SPERMATOGENISIS

Sexual Reproduction: Two parents.

• Offspring is genetically different from parents.

• Great for environmental change. Easy to evolve.

• Meiosis can better repair damaged DNA

How Proteins are Made

Pgs. 60-61

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 Fig 10-5

• 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. Overview Movie

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