WK3 7.12F and 6.12D Cells

What are the differences between a prokaryotic and eukaryote?

• The prokaryote does not have a membrane bound nucleus, but the eukaryote does

• The prokaryote has more cell structures than the eukaryote

• the prokaryote is larger

• the eukaryote has several cells

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Which of the following functions can a unicellular organism perform?

• eat

• eliminate waste

• reproduce

• all of the above

What is the main difference between a prokaryotic cell and an eukaryotic cell?

• Only prokaryotic cells have vauoles

• Eukaryotic cells are smaller than prokaryotic cells

• Prokaryotic cells have many organelles, each with their own specialized functions.

• Only eukaryotic cells have its genetic material surrounded by a membrane.

Animal Cells do NOT have_______________

• centrioles

• cell walls/ plates

• centromeres

• cytoplasm

A biology student planned an investigation to observe some of his own cells. He used a swab to get cells form the inside surface of his cheek. He put the cells n a slide and dyed them with a drop of dye. Then he put the slide under a microscope. The student observed that his cheek cells were all similar in size and shape. Next, he scraped some skin cells from his own arm. he put the cells on a slide and dyed them. The student noticed that the skin cells were a different shape than the cheek cells. He concluded that cells form different parts of his body probably had different shapes, depending on their function.

How do the biology student's observations relate to cell theory?

• The biology student saw the different cells had different shapes. This does NOT support cell theory, which states that all cells are identical.

• the biology student saw that his body was made of cells. this supports cell theory, which states that all living things are made of cells.

• The biology student saw that cheek cells were alive, but skin cells were dead. This supports cell theory, which states that nonliving things such as air or water are me of nonliving cells, while living things such as plants and animals are made of living cells.

• The biology student's observations do not relate to cell theory in any way.

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A biologist placed a Petri dish full of pond water under a high-powered microscope. She spent an hour observing the tiny organisms in the water. One of the organisms she observed was made of just one cell. she observed this organism take in nutrients from the surrounding water. It also expelled waste. The organism reproduced every 20 min, by dividing itself into two identical organisms. At the end of the hour, the first organism and its offspring had reproduces so that a total for seven organisms, each made of one cell were now in the Petri dish.

How do the biologist's observations support cell theory?

• The biologist observed that cells are composed of many smaller living things.

• The biologist observed living things that were not made from cells.

• The biologist observed that new cells come form existing cells.

• The biologist observed that every cell is different and has completely different functions.

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In 1665, the English scientist Robert Hooke published a book called Micrographia. The book contained detailed drawings of all the organisms and materials. Hooke had examined under his microscope. The book was a best seller at the time. One of the drawings shows a thin layer of cork, the bark from a cork tree. Hooke commented that the cork was divided into many "pores" or "cells" that looked like small rooms. In fact, this was the first drawing of plant cells.

How were Hooke's observations valuable int he development of cell theory?

• Hooke's observations of the "cells" in cork bark helped lead to the concept that all living things are made of cells.

• Hooke's observations of the "pores" in a thin layer of cork helped lead to the concept that the outer layer of a cell has many pores or holes in it.

• Hooke's observations on the "cells" in cork bark helped lead to the concept that nonliving things such as rocks and sand are made of cells.

• Hooke's observations on the "cells" in cork bark helped head to the concept that trees are not living organisms.

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Tom learned about cell theory in science class. He recorded four ideas about cell theory in his science notebook. One of Tom's ideas is incorrect. Which of Tom's statements is INCORRECT, according to cell theory?

• Cell theory tells what cells are, why they are important, and where they come from.

• According to cell theory, humans, cats, flowers, and ants are all made of cells.

• Cells are made of protein, lipids, nucleic acids, and water. if you mix these substances together in a beaker, cells will results.

• Cells are the smallest possible living things. If it is smaller than a cell, it cannot be alive.

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Scientists often use models to represent things that are too small to see with out microscope. The advantage of a model like the one below, which shows the interior cells of a plant leaf, is that it allows scientist to study the structure of a plant leaf and how it relates to cell theory. How does this model support cell theory.

• the model shows that although some cells obtain energy from food, other cells do not require energy at all. This supports the part of the cell theory that states all cells do not require energy

• The model shows that all the cells in a leaf are identical. This supports the part of the cell theory that states that all the cells in an organism are exactly the same.

• The model shows that leaves are made of chlorophyll, a nonliving substance. This supports the part of cell theory that states that plants are nonliving things

• The model shows that a leaf is composed of many different kinds of cells. This supports the part of cell theory that states that all organisms are composed of cells.

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The amoeba is a microorganism composed of just one cell. While the pear tree is composed of about 15 trillion cells. Which statement is NOT true, according to cell theory?

• Like an amoeba and a pear tree, all organisms are composed of one or more cells.

• The cells are both in amoeba and a pear tree carry on similar functions such as obtaining energy from food, producing waste and reproducing.

• Cell theory refers only to organisms made of just one cell, like an amoeba.

• The cells in both an amoeba and a pear tree have similar parts such as cell membranes and nuclei

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