Cell Biology Structure of plant cells Structure of

Cell Biology

Structure of plant cells:

Structure of Animal Cells:

LO: Describe the structure of cells SLE: Meet or exceed NGSS Cell diagrams: Draw a diagram that shows the organelles of plant and animal cells. Include: 1. The drawing (in color) 2. Names of the organelles 3. What the organelles do

LO: Describe the structure of eukaryotic cells. SLE: Work collaboratively. Microscope Drawings of Eukaryotes: 1. Look at several prepared slides. 2. Find two that you think are (or have) eukaryotic cells, and make a color microscope drawing of each of them. 3. If you can see them, label the cell wall/cell membrane and nucleus. (Don’t worry if you can’t). 4. These are due by the end of class today. Homework:

LO: Describe the structure of plant and animal cells. SLE: Meet NGSS Checkpoint Quiz on Cell Structure: 1. What is the difference between a prokaryotic cell and a eukaryotic cell? 2. What is the role (job) of mitochondria in eukaryotic cells? 3. Which organelle in eukaryotic cells is responsible for “constructing” proteins? 4. Name two structures that plant cells have that animal cells don’t. 5. Why are cells microscopically small?

LO: Describe the structure of plant and animal cells. SLE: Meet NGSS Checkpoint Quiz on Cell Structure: 1. What is the difference between a prokaryotic cell and a eukaryotic cell? 2. Write three main ideas of the cell theory. 3. Which organelle in eukaryotic cells is responsible for “constructing” proteins? 4. Name two structures that plant cells have that animal cells don’t. 5. Which organelle is like a storage tank for water and nutrients?

LO: Describe process of diffusion in cells SLE: Work collaboratively. Problem: How does temperature affect the diffusion rate of food coloring in water? Hypothesis: Independent variable: Dependent variable: 3 Controls: Procedure: 1. Put cold water in a beaker, add 2 -3 drops of food coloring. 2. Time how long it takes the food coloring to reach the edges of the beaker. 3. Repeat with hot water. 4. Compare diffusion rates. Data: Water Temp. (C) Cold 1 Cold 2 Cold avg. Hot 1 Hot 2 Hot avg. Conclusion: Diffusion Rate (sec)

Movement of Nutrients Within and Between Cells: Within cells, most particles move randomly through the process of diffusion: movement of particles from areas of high concentration to areas of low concentration. When water diffusion occurs through a cell or nuclear membrane, it’s called osmosis.

Diffusion and osmosis are forms of passive transport: no energy is used to move nutrients around. If energy is used to move nutrients (via proteins in the cell membrane or by Golgi bodies), it’s called active transport.

In both plant and animal cells, nutrients are usually brought into the cells, and waste removed from cells, through active and passive transport. (In animals, this is the only way that cells get nutrients. )

LO: Describe the process of osmosis SLE: Work collaboratively Problem: How does the salt concentration in water affect osmosis through egg yolk membranes? Hypothesis: Independent variable: Dependent variable: 3 Controls: Procedure: 1. Fill two beakers with water 2. Put 2 Tsp of salt in one beaker 3. Gently place an egg yolk in each beaker 4. Measure the diameter of each yolk 5. Wait 24 hours. 6. Measure the diameter of the egg yolk again and compare. Data: Initial diameter of yolks (cm) Diameter after 24 hours (cm) Fresh water: Salt water: Conclusion:

LO: Describe the process of osmosis SLE: Work collaboratively Problem: During osmosis, how do substances move through a membrane? Hypothesis: Data: Record your observations here (qualitative): (Diagram OK) Procedure: 1. Into the plastic composting bag add about 3 level teaspoons cornstarch. Add 75 ml of water, hold the bag shut and shake gently to mix. Finally, use the twist tie to seal the bag so none of the cornstarch mixture can leak out. 2. Into the clear plastic cup, add 100 ml of water and 15 drops of iodine liquid. 3. Put the plastic bag containing the cornstarch solution into the iodine solution so the part filled with the cornstarch solution is submerged inthe iodine solution. 4. Wait about 15 minutes. 5. Observe what happens and record observations. Conclusion:

LO: Describe nutrient movement within cells SLE: Meet or exceed NGSS Checkpoint Quiz on Nutrient Movement: 1. Describe how diffusion works. 2. How does temperature affect diffusion? 3. What is osmosis? 4. Describe the difference between passive and active transport. 5. What part of the cell controls what exits and enters the cell?

LO: Describe effects of salt on osmosis. SLE: Work collaboratively. Osmosis Activity #3: 1. Prepare slides from a slice of air-dried onion skin and onion skin that has been soaked in salt water. 2. Make microscope drawings of both samples. 3. What is the difference between the two samples? 4. Why is there a difference (or not a difference)?

Photosynthesis: How plant cells get energy. 6 H 2 O + 6 CO 2 C 6 H 12 O 6 + 6 O 2

Respiration: How cells use stored energy: C 6 H 12 O 6 + 6 O 2 6 H 2 O + 6 CO 2

LO: Describe cell processes SLE: Meet or exceed NGSS Pop Quiz on cell processes: 1. ) How is osmosis different from diffusion? 2. ) In which organelle in cells does photosynthesis occur? 3. ) Draw a diagram of how photosynthesis happens. 4. ) Draw a diagram of how respiration happens. 5. ) Photosynthesis and respiration are sometimes described as being almost opposites. What does this mean?

LO: Describe the effects of salt concentration on cellular osmosis. SLE: Work collaboratively. Problem: How does the salt content of water affect the rate of water absorption in plant cells? Hypothesis: Independent variable: Dependent variable: 3 Controls: Procedure: 1. Get two potato slices 2. Measure the mass of each potato slice. 3. Place one half of the potato in a beaker of salt water, and the other in a beaker of fresh water. 4. Wait two days. 5. Find the mass of each potato half again. 6. Make qualitative observations. Data: Mass of slice (g) Before: After: In Fresh water In salt water Qualitative observations: Conclusion:

LO: Describe the process of photosynthesis SLE: Work collaboratively Photosynthesis experiment: Problem: How does the intensity of light affect the rate of photosynthesis? Independent variable: Dependent variable: 3 Controls: Follow the directions in the experiment packet, and respond to the prompts (including the graph).

LO: Describe the process of cellular respiration SLE: Work collaboratively Problem: How does using more energy affect respiration? Hypothesis: Independent variable: Dependent variable: 3 Controls: Procedure: 1. Find your resting pulse. 2. Do jumping jacks for 30 seconds. 3. Find your pulse again. 4. Wait one minute, and take your pulse again. 5. Repeat steps 1 -4 with your breathing rate (# of breaths in 60 seconds) Data: Pulse: Breaths: Resting: After exercise: Recovering Conclusion: (Mention What’s happening in your Cells. )

LO: Identify inputs and outputs of cellular respiration SLE: Work collaboratively Problem: How does salt affect the process of respiration in yeast cells? Hypothesis: Independent variable: Dependent variable: 3 controls: Procedure: 1. Place yeast and sugar into two glass bottles. 2. Fill each bottle 2/3 full of warm water 3. Add salt to one of the bottles 4. Place a deflated balloon over the mouth of each bottle. 5. Wait 10 -15 minutes 6. Make qualitative observations Data: Draw a picture of each bottle. Conclusion:

The Cell Cycle:

LO: Describe the stages of the cell cycle SLE: Meet or exceed NGSS Checkpoint Quiz on Mitosis/Cell Replication: 1. Draw a cell in each stage of the cell cycle (6 points). For each stage, write one complete sentence that describes what is happening in that stage. Be sure to include, where appropriate: • Nuclear membrane • Chromosomes/chromatids • Spindles (6 points)

How can you explain what’s happening here?

The Inheritance of Traits: Mendel’s Experiments: Gregor Mendel (18221884) was an Austrian monk who, through experimenting with pea plants, started the modern science of heredity.

Mendel Chose pea plants because they self-pollinate (which makes it easy to cross plants for specific traits, and because the offspring will have all the traits of the parents) and because the traits are simple and easy to observe: • Pea color • Wrinkly-ness of peas • Height of plants • Flower color • Pod color

What Mendel discovered: 1. In the first generation of offspring (f-1), some traits were passed on, while others appeared to disappear entirely 2. In the second generation (f-2), the “disappearing” traits re-appeared to a limited extent 3. The ratio of more common traits to less common traits was always around 3: 1.

Types of Traits (According to Mendel): Dominant trait: The trait that is most likely to appear in the next generation Recessive trait: The trait that is less likely to appear, or “recede. ”

Inheritance Basics: New Words You Should Know: Gene: A segment of the DNA molecule that controls the emergence and function of a particular trait Allele: The form of a gene or set of genes that controls an observable trait (like eye color) (older term) Genotype: The combination of genes that control for a given trait (newer term) Phenotype: An organism’s observable trait or set of traits

Where genes come from: A DNA molecule contains all the instructions for the creation of all traits. The combination of all the hydrogen bases (A, T, G C), small segments, determines what traits an organism will have. The entire string of ATGC combinations is called a genome.

How the emergence of a phenotype can be predicted: The probability that a given genotype will emerge as an observable trait can be calculated using a Punnet square (if you know which genotypes are dominant and which are recessive):

Asexual vs Sexual Reproduction All organisms and cells reproduce. Most cells reproduce asexually: the cell, or single-celled organism replicates all of its DNA and divides. (In plant and animal cells, this is done through mitosis. )

Plants and animals reproduce sexually: sex cells (eggs and sperm) combine to create a new organism that inherits half of the DNA of each of the parents. Genetically, the offspring has much in common with each of the parents, but is identical to neither of them.

Meiosis: Sex cells reproduce by the process of meiosis: 1. In mitosis, chromosomes are copied once, and the cell divides once. This results in two cells that are identical to the first one. 2. In meiosis, the chromosomes are copied once, but the cell divides twice. This results in four sex cells that have half the DNA of the original one. (Note: after meiosis, sex cells do not replicate again. )

Sex chromosomes are chromosomes that determine gender. Humans have one pair of sex chromosomes: 1. If a zygote (fertilized egg) inherits two x chromosomes (XX), the resulting offspring will be female. If it inherits an x chromosome and a Y chromosme (XY), then the offspring will be male.

Sex-Linked Disorders: 1. Some disorders/diseases are caused by genetic mutations or damaged genes. They occur more often in boys than girls because girls have two x chromosomes; if one chromosome has a defective or mutated gene, there is a backup chromosome. Boys do not have this extra chromosome.

LO: Describe how traits are inherited SLE: Meet or exceed NGSS Checkpoint Quiz on Heredity: 1. Describe the difference between dominant and recessive traits. 2. In lab mice, white fur is dominant and black fur is recessive. If you observe that a mouse is black, what can you conclude about its genotype? 3. Which types of cells have half the number of chromosomes as other types of cells? 4. What are chromosomes? 5. A couple have a baby. The father has blue eyes, the mother has brown eyes, and a recessive gene for blue eyes. What is the probability that their child will have brown eyes like her mother?

LO: Describe meiosis SLE: Meet or exceed NGSS Checkpoint Quiz on Meiosis: 1. ) What types of cells are produced during meiosis? 2. ) At the end of meiosis I, how many cells are there? After Meiosis II? 3. ) Why do siblings usually look different from one another, even though they inherited genes from the same parents? 4. ) How does the number of chromosomes at the end of meiosis compare to the number of chromosomes at the end of mitosis? Why is this number important? 5. ) What determines whether a fertilized egg becomes a male or female?

The Structure of DNA Molecules:

DNA Replication:

What DNA actually does: The whole purpose of DNA is basically to tell the ribosomes what kind of proteins to make. (BTW, proteins are the building blocks of all the tissue in your body. They are chains of amino acids. The order of amino acids determines what kind of protein it is. )

How Protein is made (protein synthesis): 1. 2. 3. 4. 5. In the nucleus, a segment of the DNA molecule that codes for a particular trait unravels; this segment is called messenger RNA (m. RNA) The m. RNA travels through the cytoplasm to a ribosome. Another type of RNA, transfer RNA (t. RNA) brings amino acids to the ribosome In the ribosome, amino acids pass through the m. RNA, and are placed in the order that matches the order in the m. RNA. The ribosome continues to make copies of that protein until it receives another section of m. RNA.

The Genetic Code: The genetic code refers to the combinations of m. RNA nucleic acid bases (codons) that code for a specific amino acid. (This was discovered by Marshall Niremberg in 1960. )

LO: Design and carry out a scientific investigation. SLE: Work collaboratively Problem: Does hot water dissolve more sugar than cold water? Hypothesis: Independent variable: Dependent variable: 3 Controls: Procedure: 1. Put cold water in one beaker and hot water in another 2. Add sugar cubes to both beakers until the saturation point is reached 3. Compare how many sugar cubes were dissolved in each beaker Data: (must be quantitative) Conclusion: (5 sentences)

LO: Identify and describe the benefits and possible risks of genetic engineering SLE: Work collaboratively Questions to consider about genetic engineering: 1. What is genetic engineering? 2. What is cloning, and how can it be used to treat or cure diseases? 3. Can treating diabetes with insulin be considered a cure? Explain your reasoning in your response. 4. Why might diabetes rates be increasing among the population, especially among teenagers? 5. What are plasmids, and what is their role in genetic engineering? 6. Besides treating diabetes, what is a potential advantage to genetic engineering? 7. What is a potential risk of genetic engineering?