Question

name:
weekly graphing and data practice: gene expression
background
genes are stretches of dna that contain the instructions for making the proteins a cell needs to live and work. when genes are expressed, this means that the gene is “turned on” and can be read and used in protein synthesis to make a protein. genes are not all turned on at once: some switch on only at certain stages of development, while others are active only in specific cell types. this is what lets different cell types all with the same dna to do different jobs unique to the tissues and organs they are found in—for example, allowing muscle cells to contract or neurons to transmit signals. one gene that is expressed in many cell types is ccnd1. the ccnd1 gene codes for a regulatory protein that moves cells through the cell cycle. this allows cells to grow and divide, making more cells. scientists conducted an experiment to study how the gene ccnd1 is expressed in different cell types.

cell type	ccnd1 gene expression
nerve cells	3
epithelial cells	90
liver cells	95

graphing
create a graph on a blank piece of paper using the data in the table on the right. be sure to include all appropriate graph components such as: title, axes labels, appropriate scale, units, legend. then use the graph to answer the questions.
experimental design

1. what is the independent variable in this experiment?
2. what is the dependent variable in this experiment?
3. what testable question are scientists trying to answer in this experiment?

data interpretation

1. what is the gene expression level in nerve cells?
2. what is the gene expression level in muscle cells?
3. which cell type is the ccnd1 gene most highly expressed in?
4. what is the difference in ccnd1 gene expression between muscle and liver cells?
5. in which cell type(s) is ccnd1 gene minimally expressed?
6. write a cer: summarize how expression of the ccnd1 gene varies across cell types. support your claim with evidence.

Explanation:

Experimental Design

1.

The independent variable is the factor that is manipulated or changed in an experiment. Here, the experiment studies CCND1 gene expression in different cell types, so the cell type is the independent variable as it's what's being varied to observe changes in gene expression.

The dependent variable is what is being measured or observed as a result of the independent variable. In this experiment, we measure CCND1 Gene Expression based on different cell types, so it's the dependent variable.

A testable question should relate the independent and dependent variables. The experiment looks at how CCND1 gene expression differs across cell types, so the question is about the relationship between cell type and CCND1 gene expression.

Answer:

Cell Type

2.