Module 1 Lots and Lots of Cells Online Lab PDF

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Mandatory lab practicals assignments...

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Frankline Olum

Lots and Lots of Cells Cell division has several purposes: 

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Reproduction – Organisms use mitosis for asexual reproduction. The resulting offspring are genetically identical to the parent. Meiosis allows for sexual reproduction. The reduction in the number of chromosomes allows for the joining for genetic material from two different parents. The added diversity can increase the chance of surviving environmental changes. Growth and Development – Producing new cells allows for increase in body size of multicellular organisms. During development cells become specialized for different functions. Although they all have identical genes, they differ in which genes they express. Tissue Repair – When cells die they need to be replaced. Mitosis provides for this process.

Day 1: Procedure: Complete this activity as soon as possible during the first week. 1. Obtain one of the following plants: Wandering Jew (Tradescantia sp.), or Coleus (Coleus sp.). You may already have one of these in your home. (There are pictures of these plants in the lab PowerPoint.) 2. Cut a branch with several sets of leaves from the plant. 3. Place the branch, cut end down, into a container of water. 4. Take a picture of the plant and paste it below.

Day 2: Complete the rest of the lab during Module 2. Part 1. Asexual Reproduction Part 1A: Single celled organisms When single celled organisms undergo cell division they create new organisms. In prokaryotic organisms, the process is called binary fission. In eukaryotic organisms, the process is mitosis. Paramecium is a single celled organism that lives in the water swimming with cilia. It feeds on pieces of debris and bacteria.

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Procedure: 1. Observe the picture of Paramecium undergoing asexual reproduction in the lab PowerPoint. 2. How does the size of the parent cell compare with the size of the daughter cells? The parents cell is twice as big, the daughter cells seems exact half each of the parent cell. 3. What will have to happen before the daughter cells are ready to reproduce? It must go through a period known as interphase during which it grows and produces the various proteins necessary for division. 4. Do the parent cell and daughter cells have the same or different genes? Explain. Because it is a sexual reproduction, the resulting two daughter cells have the same number and type of genes as the original cells. The daughters are clone. Part 1B: Fungi Most fungi are capable of undergoing both sexual and asexual reproduction. When fungi reproduce they create spores either through mitosis (asexual reproduction) or meiosis (sexual reproduction). The structure containing asexual spores is called a sporangium. The body of the fungus is a series of thread like structures called hyphae. Procedure: 1. Observe the pictures of Rhizopus (bread mold) sporangia in the lab PowerPoint. 2. How does the number of offspring produced for the fungus compare to that of the Paramecium? The fungus produces a lot of offspring maybe to increase the chances of survival unlike the paramecium that the number of offspring is known from the parent’s cell division which can either be two daughter cells or 4. 2

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3. The sporangia of bread mold are visible above a slice of bread, while the hyphae are inside the bread. Why do you think the fungus has this arrangement? The sporangia are up in the air because when conditions are appropriate, it produces/releases spores into the air and will fall and start to germinate to form hyphae.

Part 1C: Plants Most plants are capable of undergoing both sexual and asexual reproduction. The type of plant will determine which part(s) (roots, stems, and leaves) are capable of growing into a complete plant. Procedure: 1. Obtain the plant cutting you made on the first day of class. Paste a picture of what you cutting looks like now below. 2. What new organs are growing on the cuttings of plant stems?

3. What is the advantage of being able to grow new parts?

4. Why can the plant grow new parts but we cannot?

Part 1D: Animals Most animals are not capable of asexual reproduction. Some more primitive animals such as hydra (a relative of jellyfish) are able to bud or go through

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fission. Some more advanced animals are capable of parthenogenesis. These species exist only as females that can reproduce without fertilization. Procedure: 1. Observe the picture of a hydra budding in the lab PowerPoint. 2. How does the size of the parent compare with the size of the bud? The hydra makes offspring by forming buds that break off and grow into new hydras like the parent therefore the size of the parents is much bigger than the buds. 3. Do the parent and bud have the same or different genes? Explain. As this is asexual reproduction, the newly developed organism is a replica of the parent and is genetically identical.in other words, its not as a results of two sexes where each partner contributes half of the chromosomes but rather happens a sexually from the same single parent.

4. Name two additional animals that can undergo asexual reproduction. Describe how they reproduce asexually. 1. Yeast- In yeast, budding usually occurs during the abundant supply of

nutrition. In this process of reproduction, a small bud arises as an outgrowth of the parent body. Later the nucleus of the parent yeast is separated into two parts and one of the nuclei shifts into the bud. The newly created bud divides and grows into a new cell. 2. Flatworm- a flatworm grows an extension from its body. This extension, or bud, becomes a new worm and separates from the original flatworm.

Part 2. Development Multicellular organisms begin life as a zygote, which is a fertilized egg. From there they must undergo two processes to become a mature organisms: cell division and cell differentiation.

Part 2A. Early Development

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During early development animals undergo rapid cell division and change shape to develop tissue layers. Primitive animals, such as jellyfish and sea anemones, have two tissue layers: ectoderm and endoderm. Ectoderm forms the outer layer of the organisms and the nervous system. Endoderm forms the lining of the digestive tract and respiratory system. The differentiation into endoderm and ectoderm occurs during a process called gastrulation. More advanced organisms go through additional differentiation to form a third tissue layer, the mesoderm, which will become muscle, skeleton, and other internal organs.

After formation through the joining of an egg and a sperm, the zygote divides rapidly through the process of mitosis to form a solid ball of cells called a morula. The cells then migrate to the outside of the ball forming a hollow ball called a blastula. After formation of the blastula, cell begin to migrate into the center of the ball forming the primitive gut (gastrulation). During this process the cells differentiate into ectoderm and endoderm. Procedure: 1. Observe the pictures in the lab Powerpoint of a slide of a containing the early development stages of a sea star.

Describe each stage below. Zygote Shortly after fertilization, the vitelline membrane lifts off the egg cell membrane to become the fertilization membrane. This functions as permanent block to polyspermy and is a distinguishing difference between fertilized and unfertilized eggs. Morula During the early period of cleavage, as in the 16- and 32-celled stages, the blastomeres are packed together like a cluster of mulberries, and the embryo is referred to as the morula. Blastula

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As cleavage continues a fluid filled blastocoel forms and the blastomeres become displaced into an organized peripheral monolayer of cells; the embryo is now referred to as a blastula. Gastrula During gastrulation, the blastocoel is displaced and a new cavity, the archenteron, is formed. The opening into the archenteron is the blastopore and develops into the anus in all deuterostomes.

2. Which cells of the gastrula will become ectoderm and which cells will become endoderm. The ectoderm will give rise to the nervous system and the epidermal skin cells while endoderm gives rise to digestive system.

3. What body parts do the ectoderm cells become? Nervous system

4. What body parts do the endoderm cells become? Digestive system.

5. How does the size of a blastula compare to the size of a zygote? Blastula is relatively larger but not to a greater extent. 6. A zygote is a single cell, while a blastula is made of many cells. What does this tell you about the size of a cell in a blastula? smaller 7. What will need to happen for the embryo to grow in size? Differentiation

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Part 2B. Metamorphosis Following the embryo stage, a long period of further development begins. At a minimum there is a change in size. For some organisms there is also a change in body form called metamorphosis. During the lives of many insects we see distinct stages that are often accompanied by changes in habitats and eating habits. The changes are dramatic:  

The larva is an active, worm-like stage that eats constantly. The pupa usually seems inactive, but actually is transforming larval tissues into the adult body. It may be hidden inside a cocoon or case of some kind.  The adult is finished developing, and is able to reproduce.

Amphibians, such as the frog, also change form (and habitat and diet) during their lives. Procedure 1. Observe the pictures of the different stages of the mealworm life cycle in the lab PowerPoint. 2. What are the primary functions of each stage in the insect life cycle? Larva – to eat nutrients abundant food and store them for the next lifecycle stage.

Pupa – offer protection from the outside danger, be it harsh weather or predators.

Adult – to find a mate and produce the next generation of its species(procreate)

3. How is each stage adapted to perform its function?

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1. Larva-is considered an eating machine, it eats everything on its way, for instance the locust larva in East Africa currently is eating anything green on their path. 2. Pupa-formation of a cocoon, it is the same color as the things around it(camouflage). Things like the trees, leaves, or branches. This is so that other animals cannot see it. This protects them. 3. Adult-a complete adult insect with head, wings, legs, eyes, antenna, body that will enable it to move around, look for food, mates, lay eggs etcetera.

4. You are probably all familiar with the life cycle of a butterfly. (If not review the diagrams on the side counter.) Sketch the stages and paste pictures of you sketches below. Larva

Pupa

Adult

5. Complete metamorphosis, as seen in the butterfly, is thought to have evolved to reduce competition between young and adults. Both the larval and adult Monarchs depend on the milkweed plant for food. How do the larva and adult butterfly partition their food resources so that they do not complete? Adult butterfly is able to move freely hence have large surface area for food leaving the leaves for the larva. They also have different food preferences largely due to the structure of their mouth parts.

6. Observe the stages of frog metamorphosis in the lab Powerpoint. Make comparisons in the table below: 8

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juvenile (tadpole)

diet

plants

adult

Insects, earthworms

In ponds,(water)

land

habitat

Body form; organs appropriate for that habitat and diet

have rudimentary gills Lungs to breathe in land, for breathing in water, a hindlegs to jump and mouth for eating, and a disappeared tail. long tail for swimming

Part 2C. Cell Specialization Procedure 1. Observe the cross section of a human intestine in the lab PowerPoint. 2. How many different tissues are visible? four 3. What different functions would different tissues perform in this organ? 

4. What tissue layers (ectoderm, endoderm, mesoderm) do you think these tissues from from? Ectoderm-Epidermis 9

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Endoderm- lining of airwaves including digestive system. Mesoderm-connective tissues

5. Observe the cross section of a plant leaf In the lab PowerPoint. 6. How many different tissues are visible? Four

7. What different functions would different tissues perform in this organ?

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