General Cell Structure
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00:01: General cell structure. According to cell theory, we know that all living things are made up of one or more cells. If we look at any cell, we'll see the following. We'll see the cell bounded by a membrane, we'll see that the cell has some sort of genetic material in it, and we'll also see that the cell contains a viscous liquid-like substance called cytoplasm. But we can take all cells and divide them into two main groups. 00:34: Scientists believe that the first cells on earth were probably prokaryotic. Prokaryotic cells are primitive cells, so think P for primitive. While they do have a membrane and genetic material and a cytoplasm, they don't have much more. Now, you may have studied cell models in the classroom, and when you study cell models you're looking at eukaryotic cells. That prefix U means true. When we look at true cells now in class we're looking at cells that have organelles, but we'll come back to that in just a minute. Prokaryotic cells, because they're primitive, are smaller and they lack the major cellular organelles. They don't have a nucleus, their genetic material is loose in the cytoplasm. If they are photosynthetic, the chlorophyll is not in a chloroplast. And the only organelle that is present in prokaryotic cells are ribosomes. So if we look back, prokaryotic cells are primitive, they're very simple, and they're small. They're what we call today in our modern classification scheme, bacteria: Eubacteria and archaebacteria. We used to call them several, several, several years ago, the monerans. 01:49: On the other hand, eukaryotic cells are organized and more complex. They have all the major cellular organelles. The genetic material DNA is in the nucleus. If these eukaryotic cells are autotrophic, for example plant cells or some algae, the chlorophyll is in a chloroplast. So be sure to remember that all cells have some common characteristics, but be sure to go back and review the differences between prokaryotic and eukaryotic cells.
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Question 1
The first organisms on Earth were mostly likely ________ cells.
Responses
A prokaryoticprokaryotic
B eukaryoticeukaryotic
Question 2
A(n) ________ cell has a nucleus and typical organelles.
Responses
A prokaryoticprokaryotic
B eukaryoticeukaryotic
Question 3
All cells contain ____________.
Responses
A only DNAonly DNA
B only RNAonly RNA
C DNA, RNA, or Both
C DNA, RNA, or Both
Question 1: The first organisms on Earth were mostly likely ________ cells.
Response: A) prokaryotic
Question 2: A(n) ________ cell has a nucleus and typical organelles.
Response: B) eukaryotic
Question 3: All cells contain ____________.
Response: C) DNA, RNA, or Both
Question 1: The first organisms on Earth were most likely ________ cells.
To answer this question, we need to understand the information provided in the video. According to the video, the first cells on Earth were probably prokaryotic cells. Prokaryotic cells are described as primitive cells and they lack major cellular organelles. They are smaller in size and their genetic material is loose in the cytoplasm. The video also mentions that prokaryotic cells are what we now classify as bacteria: Eubacteria and archaebacteria.
Therefore, the answer to Question 1 is: A) prokaryotic.
Question 2: A(n) ________ cell has a nucleus and typical organelles.
To answer this question, we need to understand the information provided in the video. The video explains that eukaryotic cells are organized and more complex. They have all the major cellular organelles. The genetic material DNA is located in the nucleus of eukaryotic cells. If these cells are autotrophic, such as plant cells or some algae, the chlorophyll is found in a chloroplast.
Therefore, the answer to Question 2 is: B) eukaryotic.
Question 3: All cells contain ____________.
To answer this question, we need to understand the information provided in the video. The video states that all cells have some common characteristics. These common characteristics include being bounded by a membrane, containing genetic material, and having a viscous liquid-like substance called cytoplasm. Therefore, all cells contain genetic material.
Therefore, the answer to Question 3 is: C) DNA, RNA, or Both.