Unit 2 Exam Study Guide Flashcards
1
Q
What is correlation?
A
Correlation is any statistical relationship, whether causal or not, between two random variables.
2
Q
What is causal?
A
When one variable causes the other variable to change, that is a causal relationship.
3
Q
True or false: some correlations are obviously meaningless.
A
True. Ex. Divorce rates in Main declined at a similar rate as the consumption of margarine per capita.
4
Q
Scientists established a correlation between what two things?
A
Smoking and cancer
5
Q
Lung cancer was rare in 1900, but by 1940, it was becoming…
A
the most common cancer diagnosed in American men.
6
Q
From 1920-1940, scientists tested four different hypotheses for what was causing lung cancer:
A
- More Pollution
- Street pavement products like asphalt
- Chemicals used in WW1
- Tobacco use
7
Q
What two types of studies were conducted to establish a causal relationship between cigarettes and lung cancer?
A
- Observational studies
- Experimental studies
8
Q
By the _____ the evidence was clear that cigarette smoking was causing cancer.
A
1950s
9
Q
Several _____________ issued ___________ about the risk of cancer from smoking.
A
professional associations (ex. American Heart Association, American Cancer Society), consensus statements
10
Q
What is consensus?
A
Consensus in science is a position held by most scientists in a particular field and at a particular time. Based on best available evidence.
11
Q
What was the purpose of the Tobacco Industry Research Committee (1954)?
A
They hired scientists who said the results (tobacco causing lung cancer) were controversial.
12
Q
What were four of the Tobacco Industry Research Committee’s claims?
A
- Not all scientists agreed
- Not everyone who smokes develops lung cancer
- Scientists don’t know how smoking causes lung cancer.
- Scientists have not proven that smoking causes lung cancer.
13
Q
Some areas of science, _____________, have a lot of scientific debate.
A
particularly emerging science
14
Q
Over time some areas of emerging science…
A
can become more settled, and consensus builds.
15
Q
A few areas in science where there is little debate among scientists (ex. strong consensus)…
A
have generated a lot of controversy in society.
16
Q
What are three ways to find the scientific consensus?
A
- Reliable news sources will show broad general agreements in science.
- Scientific journals publish peer-reviewed papers discussing the level of consensus on an issue.
- Professional societies will publish “consensus statements” on their discipline’s topic.
17
Q
_____________ can make recommendations.
A
Government agencies
18
Q
In _____, the ___________ put out a report based on a summary of all available evidence between smoking and lung cancer.
A
1964, US Surgeon General
19
Q
What two factors did the US Surgeon General’s report conclude?
A
- The main cause of the increase in lung cancer was smoking tobacco.
- Smokers were 10 to 20 times more likely to get lung cancer than nonsmokers.
20
Q
What are three ways in which the US Surgeon General’s recommendations affect society?
A
- Restrictions on smoking in public spaces.
- Labels on cigarette packages.
- Restrictions on advertising.
21
Q
In _____, about ___ adults smoked cigarettes.
A
2020, 12.5%
22
Q
What are case-control studies?
A
Case-control studies are observational studies. Compare groups of people who have a condition to people without; looking for risk factors.
23
Q
What is an experimental study?
A
Hypothesis-driven controlled experiments that allow scientists to change variables.
24
Q
What is a prospective cohort study?
A
Is a type of observational study. Prospective means that they follow individuals to see what happens to them in the future.
25
What is a Meta Analysis?
Meta-analysis is a type of study that examines data from many different independent studies.
26
What is an anecdote?
A person's story from personal experience; unreliable. However, anecdotal evidence may inspire scientific questions.
27
Cancer is a ________________ caused by ___________.
Cancer is a group of diseases caused by uncontrolled cell division.
28
Cancer starts when...
a cell loses control of cell division.
29
A cell that keeps dividing will...
form a mass of cells that all keep dividing.
30
What functions does a growing mass (cancer) disrupt?
It disrupts the functions of organs, produces toxins, takes up nutrients, and spreads to other tissues.
31
Cancers are characterized by...
where they start.
32
What is the cell type that starts the cancer called?
The primary cancer
33
What are the cancers called where the cancer spreads?
The secondary cancers
34
True or false: Cells make up all organisms.
True
35
True or false: All cells come from other cells.
True
36
Cells are ___________ (which means that cells can perform all of life's functions).
the smallest unit of life
37
What are scientific theories?
They are broad explanations of natural phenomena. They are supported by a lot of evidence.
38
What are hypotheses?
They are possible explanations that can be tested. Evidence can either support or reject a hypothesis.
39
What are the seven properties of life:
1. Obtain and use energy (fuel) (photosynthesis/cellular respiration)
2. Respond to stimuli in the environment (cells respond to infection)
3. Maintain homeostasis (regulation) (cell membrane regulates what gets in/out)
4. Reproduction/pass on genetic information (DNA) (cells can divide)
5. Grow and develop (cells turn into specialized cells)
6. Evolve (cells fight bacteria)
7. Order
40
___________ of living organisms evolve (change) over generations.
Populations
41
What are the two categories of cells?
Prokaryotic and Eukaryotic cells
42
What are prokaryotic cells? Where are these cells found?
1. Unicellular organisms
2. Much smaller than eukaryotic cells.
3. Ex. bacteria, archaea
43
What are eukaryotic cells? Where are these cells found?
1. Unicellular and multicellular organisms
2. Ex. Plant cells, animal cells, yeast, algae
44
True or false: prokaryotic and eukaryotic cells all look different but have similar basic structures.
True
45
Because eukaryotic cells are bigger than prokaryotic cells, they have "___________" or _________.
compartments, organelles
46
What are stem cells?
Cells developing in organisms that are capable of dividing and becoming any cell in the body are called stem cells.
47
What is the process of differentiation?
Stem cells can become any cell in the body through a process called differentiation.
48
Differentiated (___________) cells make different proteins.
specialized
49
Different genes are turned _____ in different cell types.
on/off
50
True or false: Some organisms have a lot of stem cells as adults.
True
51
True or false: A virus cannot do anything outside a cell.
True
52
True or false: A virus is a cell
False. A virus is NOT a cell.
53
Viruses contain genetic information in the form of ____ or ____.
DNA, RNA
54
A virus cannot divide, cannot use energy and grow, it cannot change over time _________.
unless it infected a cell.
55
Viruses hijack ____ functions
cells'
56
A virus uses a cell's machinery (________ and _______) to make more copies of itself.
enzymes, ribosomes
57
A virus can _____ (change) over time into different ______.
evolve, strains
58
What is order as it pertains to the properties and process of life?
Living organisms are highly organized structures that consist of one or more cells. Inside each cell, atoms make up molecules, and molecules make up cell components or organelles.
59
What is response to stimuli as it pertains to the properties and process of life?
Organisms respond to diverse stimuli in their environment. (Ex. plants bend toward source of light, tiny bacteria move toward/away from chemicals).
60
What is reproduction as it pertains to the properties and process of life?
A single-celled organism reproduces by dividing into two new cells. The DNA of an organism is passed to offspring. This is why offspring have similar characteristics to the parent.
61
Many _____________ organisms (those made up of more than one cell) produce _______________ (called _______) that combine to form new individuals.
Many multicellular organisms (those made up of more than one cell) produce specialized reproductive cells (called gametes) that combine to form new individuals.
62
What is growth and development as it pertains to the properties and process of life?
Organisms grow/develop according to DNA. These instructions are encoded in segments of DNA called genes. Multicellular organisms grow through cell division.
63
What is regulation/homeostasis as it pertains to the properties and process of life?
Refers to the stable internal environment required to maintain an organism's survival. Organisms require mechanisms to coordinate internal functions. (Ex. polar bear regulating constant body temp, systems carrying oxygen throughout the body)
64
What is obtain/use energy as it pertains to the properties and process of life?
Organisms need a source of energy to power activity and matter to build cells. (Ex. capture energy from sun to convert into chemical energy, organisms using chemical energy from cells they take in).
65
What is evolution as it pertains to the properties and process of life?
Is the process by which populations change over time. When variations are inherited, individuals with characteristics of survival/reproductive advantage in an environment are more likely to pass down genes.
66
What are evolutionary adaptations?
Over time, the population will change to have more of the evolutionary characteristics. Characteristics that make organisms well-suited to their environments are evolutionary adaptations.
67
Living things follow a ____________ on a scale from small to large.
hierarchy
68
What is an atom?
The atom is the smallest unit of matter and retains the properties of an element.
69
What is a molecule?
Atoms form molecules. A molecule is a chemical structure consisting of at least two atoms held together by a chemical bond.
70
What is an example of a molecule?
Deoxyribonucleic acid (DNA)
71
Some cells contain aggregates of large molecules surrounded by membranes, which are called __________.
organelles
72
What are organelles?
Organelles are small structures that exist within cells and perform specialized functions.
73
All living things are made of ______; _________ itself is the smallest fundamental unit of life.
cells, the cell
74
Some organisms consist of a __________ and others are ____________.
single cell, multicellular
75
What are tissues?
In most multicellular organisms, cells combine to make tissues, which are groups of similar cells carrying out the same function.
76
What are organs?
Organs are collections of tissues grouped together based on a common function.
77
What is an organ system?
An organ system is a higher level of organization that consists of functionally related organs.
78
What are organisms?
Organisms are individual living entities.
79
Single-celled organisms are typically referred to as ______________.
microorganisms
80
What is a population?
All the individuals of a species living within a specific area are collectively called a population. Ex. all the pine trees of a forest represent the population of white pine trees. Different populations may live in the same area.
81
What is a community?
A community is a set of populations inhabiting a particular area. Ex. all trees, flowers, insects, and other populations in a forest form the forest's community.
82
What is an ecosystem?
An ecosystem consists of all the living things in a particular area together with abiotic factors.
83
What is the biosphere?
The biosphere is the collection of all ecosystems, and it represents the zones of life on Earth. Ex. land, water, portions of the atmosphere.
84
Order the levels of organization of living things from smallest to largest.
Atom, molecule, organelle, cell, tissues, organs, organ system, organisms, population, community, ecosystem, biosphere.
85
Just as the atom is _____________, the cell is __________.
the smallest unit of matter, the smallest unit of life
86
All living organisms are made of _____ and single cells exhibit _____________.
cells, the properties of life
87
What is cell theory?
Cell theory states that all living things are composed of one or more cells, the cell is the basic unit of life, and all new cells arise from existing cells.
88
True or false: Eukaryotes can be either unicellular or multicellular.
True. (Ex. Yeast is a unicellular organism, a dog is multicellular).
89
All cells (prokaryotic and eukaryotic) share four common components:
1. A plasma membrane (cell membrane)
2. Cytoplasm
3. DNA
4. Ribosomes
90
What is a cell membrane?
An outer covering that separates the cell's interior from its surrounding environment.
91
What is cytoplasm?
Consisting of the jelly-like substance that fills the cell in which other cellular components are found.
92
What is DNA?
The genetic material of the cell.
93
What are ribosomes?
Particles that synthesize proteins.
94
What are components of prokaryotic cells? What do they lack?
It's a simple, single-celled (unicellular) organism that lacks a nucleus or any other membrane-bound organelle.
Prokaryotic DNA is found in the central part of a prokaryotic cell. Many prokaryotic cells also have a cell wall surrounding the cell membrane.
95
What is a cell wall?
It's a rigid covering that protects the cell, provides structural support, and gives shape to the cell.
96
What are the components of eukaryotic cells?
It's a cell that has a membrane-bound nucleus and other membrane-bound compartments or sacs, called organelles, which have specialized functions.
97
What is the nucleus?
It houses the cell's DNA and directs the synthesis of proteins and ribosomes.
98
In eukaryotes, the DNA in the nucleus of a cell is...
divided into segments called chromosomes.
99
Every species has a specific number of __________ in the nucleus of its body cells.
chromosomes
100
What is the mitochondria?
Mitochondria are called the "powerhouses" of a cell because they are responsible for converting chemical energy in nutrients to cellular energy (ATP).
101
A cell typically contains several ______________.
mitochondria
102
Mitochondria are ___________, __________ organelles that have their own _________ and ___.
Mitochondria are oval-shaped, double-membrane organelles that have their own ribosomes and DNA.
103
Like mitochondria, ___________ also have their own DNA and ribosomes.
chloroplasts
104
Although mitochondria are found in both _______ and ______ cells, ________ are found only in organisms that can perform ______________, such as ________ and _______.
Although mitochondria are found in both animal and plant cells, chloroplasts are found only in organisms that can perform photosynthesis, such as plants and algae.
105
In photosynthesis, _________, _____, and __________ are used to make _______ and ______.
In photosynthesis, carbon dioxide, water, and light energy are used to make glucose and oxygen.
106
What are chloroplasts?
Chloroplasts contain a green pigment called chlorophyll, which captures the energy of sunlight.
107
Like plant cells, ______________ also have __________.
photosynthetic protists, chloroplasts.
108
Some bacteria also perform ___________, but they do not have __________. Their photosynthetic pigments are located within the cell itself.
photosynthesis, chloroplasts
109
What is symbiosis?
Symbiosis is a relationship in which organisms from two separate species live in close association.
110
What is endosymbiosis?
Endosymbiosis is a relationship in which one organism lives inside the other.
111
Scientists have long noticed that ________, _________, and __________ are similar in size and have other similar features.
bacteria, mitochondria, chloroplasts
112
In the 1950s and 1960s, scientists discovered that __________ and __________ have their own ___ and __________, just as bacteria do.
In the 1950s and 1960s, scientists discovered that mitochondria and chloroplasts have their own DNA and ribosomes, just as bacteria do.
113
Cell membrane: Is it present in prokaryotes, animal cells, and/or plant cells?
Present in all three
114
Cytoplasm: Is it present in prokaryotes, animal cells, and/or plant cells?
Present in all three
115
Nucleus: Is it present in prokaryotes, animal cells, and/or plant cells?
Only present in animal and plant cells.
116
Ribosomes: Is it present in prokaryotes, animal cells, and/or plant cells?
Present in all three.
117
Mitochondria: Is it present in prokaryotes, animal cells, and/or plant cells?
Only present in animal and plant cells.
118
Cell wall: Is it present in prokaryotes, animal cells, and/or plant cells?
Present in prokaryotes (not in archaea) and present in plant cells (primarily cellulose)
119
Chloroplasts: Is it present in prokaryotes, animal cells, and/or plant cells?
Only present plant cells.
120
Bacterial cells divide to make more of themselves (____________).
reproduce
121
One cell copies its ____, which carries the _________ for building and running the cell.
DNA, instructions
122
After copying its DNA, then the cell _____ to produce ___________ (ex. from one organism to two organisms).
divides, two identical cells
123
Human and other __________ organisms have _______ of cell division.
multicellular, two types
124
What are the two types of cell division in multicellular organisms?
1. To produce lots of body cells (somatic cells) from one initial cell.
2. To produce gametes (egg and sperm) which will combine to produce a new organism.
125
What are the three purposes of the somatic (body) cell division process?
1. Cells divide for us to grow from one cell to many.
2. When we stop growing, cells divide to repair damaged tissues or replace dead cells.
3. In somatic cell division one cell divides into two identical cells.
126
What are the steps of the somatic (body) cell division process?
1. G1 (Cell growth): the cells grow
2. S (DNA synthesis): The cell doubles its DNA
3. G2 (DNA error check): The cell grows some more and repairs any errors in DNA
4. Mitosis: The cell divides
127
What is the Resting State (G0) of the cell cycle?
Cells can also exit the cell cycle and enter a Resting State called G0. Specialized cells are usually in G0.
128
What three factors determine the rate at which cells divide?
Different cells divide at different rates. The rate depends on your body's need for that cell type, the span of that cell type, and how many of that cell type you have.
129
Cancer is a disease of...
too much cell division.
130
Cancer starts with one body cell with a ________ that loses control of cell division.
mutation
131
What are mutations?
Mutations are changes in a cell's DNA.
132
Mutations can happen when...
a cell copies its DNA in the DNA synthesis phase (they are like typos).
133
Most mutations don't do anything but some mutations can affect ______.
genes
134
Chromosomes contain _____.
genes
135
What are genes?
Segments of DNA that determine our characteristics are called genes.
136
What do most genes carry?
Most genes carry instructions (code) for making proteins, which build and run our cells.
137
Order the components of a chromosome from smallest to largest.
Protein, gene, chromosome
138
____________ in genes can cause changes in proteins.
Mutations
139
Which component of a chromosome has a mutation?
Protein, gene (mutation occurs), chromosome
140
Why are humans more likely than elephants to get cancer?
P53 encodes a "checkpoint" protein. Elephants have 40 copies of the p53 gene whereas humans have 2 copies of the p53 gene on chromosome 17.
141
Each pair of the genes are generally the same length and carries the same genes (except for ______________).
the sex chromosomes
142
Checkpoint proteins regulate __________.
cell division
143
What is the purpose of checkpoint proteins?
Some checkpoint proteins normally tell the cell to divide (to replace a dead cell). Some tell it to stop dividing (no more cells are needed/cell is damaged).
144
If a cell has damaged DNA...
checkpoint proteins stop it from going to the next step in the cell cycle (G0).
145
What is apoptosis?
A cell stops dividing, the damage is repaired. If the damage can't be repaired, the cell self-destructs (apoptosis).
146
There are two main types of genes that code for checkpoint proteins. They fall into which two categories?
Proto-oncogenes and tumor suppressor genes
147
What are proto-oncogenes?
Proto-oncogenes produce proteins that tell the cell to divide.
148
What are tumor suppressor genes?
Tumor suppressor genes produce proteins that tell the cell to stop or slow down cell division.
149
What happens when proto-oncogenes mutate?
Mutations in proto-oncogenes cause the proteins to become overactive.
150
When a proto-oncogene is mutated, what is it called?
It's called an oncogene. They're capable of transforming a regular cell into a cancer cell.
151
What happens when tumor suppressor genes mutate?
Mutations in tumor suppressor genes inactivate the protein.
152
P53 is a...
tumor suppressor gene
153
What are three ways in which p53 controls cell division?
1. p53 tells the cell to stop dividing to repair its mutations or self-destruct.
2. If you have a mutation in one copy of p53, you still have the other one that works.
3. If both p53 copies are mutated the cell might divide uncontrollably.
154
Risk estimates for cancer and other diseases are determined by studying _____________ and _____________.
large groups of people, calculating averages
155
What are two ways in which risk is communicated?
Absolute risk and relative risk.
156
What is absolute risk?
The absolute value. For cancer, it's often a lifetime risk. (Ex. 12 out of 100 men will develop prostate cancer).
157
What is relative risk?
A comparison rather than an absolute value. (Ex. the risk of lung cancer for smokers is 25 times higher than for non-smokers).
158
Cancer develops as...
many mutations accumulate.
159
A cell with mutations will start to divide more and _______________.
accumulate more mutations
160
As cells accumulate more and more mutations...
cells become more abnormal. Eventually, cancer cells invade other issues.
161
What are two reasons age is a major risk factor for cancer?
1. Age is a major risk factor for cancer partly because the cells of older people will have accumulated more mutations.
2. Repair mechanisms and the immune system may not function as well.
162
Why is family history a major risk factor for cancer?
Someone can inherit a mutated copy of a gene (Ex. BRCA1).
163
Why are infections a major risk factor for cancer?
Several viruses are known to increase the risk of cancer in humans.
Some viruses insert their DNA/RNA into the host cell and cause the host cells to lose control over cell division.
164
Human papillomavirus (HPV) is the most common _________ in the world.
sexually transmitted virus
165
Some _____ of HPV can cause cancer. They contain ___________.
strains, oncogenes
166
What are the main four risk factors that cause cancer?
1. Age
2. Family history
3. Lifestyle
4. Infections
167
All the _________ cause mutation to DNA, which are ultimately the cause of _____.
risk factors, cancer
168
What five factors do doctors look for in a cancer diagnosis?
1. Where the cancer and possibility for surgery?
2. How fast cancer cells are dividing (mitotic index)?
3. How big is the cancer?
4. Have cancer cells moved to other parts of body?
5. What are the genetic mutations in cancer cells?
169
What are three purposes of performing surgery on cancer?
1. It's the oldest treatment.
2. Remove cancer cells from the body
3. Works when cancer is solid and all in one place
170
What is chemotherapy?
It's a drug treatment that uses powerful chemicals to kill all fast-dividing cells in your body.
171
What are the three steps in which radiation therapy works?
1. High energy X-rays and gamma rays are pointed at the cancer.
2. Damages and kills healthy and cancer cells.
3. Often given together with chemotherapy.
172
What is targeted therapy?
Doctors design treatments that target specific proteins present in cancer cells but not healthy cells.
173
What is immunotherapy?
Immunotherapy "trains" immune cells in the body to target specific cancers. Immune cells can recognize abnormal cancer and kill it. Less damage to healthy cells.
174
What are four factors to early detection/prevention:
1. HPV vaccine
2. Minimize exposure to cancer-causing agents
3. Healthy lifestyle
4. Screenings
175
What are three characteristics common to all life forms?
Reproduction, growth, and development
176
What is a genome?
A cell's complete set of DNA is called a genome.
177
Most genes contain the instructions (___) for the cell to make proteins; another way of saying this is mat most genes ___ for proteins.
code, code
178
The ____ consists of a series of carefully timed and regulated phases of growth, DNA replication, and division.
cell cycle
179
The cell cycle has two major phases _________ and the _______- that can be divided into smaller phases.
interphase, mitotic phase
180
What happens during the interphase of the cell cycle?
The cell grows and DNA is replicated.
181
What happens during the mitotic phase of the cell cycle?
The replicated DNA and cytoplasmic contents are divided equally among the two new cells.
182
What steps of the cell cycle are part of the interphase?
G1, S, and G2
183
What steps of the cell cycle are part of the mitotic phase?
Mitosis phase
184
What is cytokinesis?
Is the process in which the cytoplasm is divided between the two new cells.
185
Where are the "checkpoints" located during cell division?
Near the end of G1, near the end of G2, and during the mitosis transition.
186
What happens at the G1 checkpoint?
Makes sure cell is grown enough for cell division and that there are no errors with DNA.
187
What happens at the G2 checkpoint?
These mechanisms assess whether all the DNA is properly duplicated.
188
What happens at the M checkpoint?
Regulatory mechanisms monitor whether the chromosomes are properly positioned and attached to the cell's spindle apparatus (pulls paired chromosomes to opposite ends of the cell).
189
Eukaryotic unicellular organisms (yeast) reproduce by proceeding through the ______. Prokaryotic organisms (bacteria) reproduce by a simpler process called _________.
cell cycle phases, binary fission
190
What are the rules for using human cells and tissues in research?
A study has to go through a review process and participants have to provide "informed consent" to participate (Common Rule).
191
What does the Common Rule not apply to?
It doesn't apply to cells or tissues removed during medical procedures. Scientists can use leftover tissues/cells if the patient's identity is removed.
192
What is a randomized controlled trial?
Used to test treatments in a large study.
193
What is a case report or case series study?
Studies a single person or several people without a comparison group (control).
194
What are animal and laboratory studies?
Experiments that do not involve humans; very important for understanding mechanisms.
195
How does information in DNA result in proteins?
Through transcription and translation.
196
What is transcription?
Making an mRNA copy of a gene on DNA in the nucleus.
197
What is RNA?
RNA copies and translates genetic codes to build these proteins.
198
What is translation?
Turning the copied mRNA into protein by decoding the mRNA at the ribosome.
199
What is an epidemiological study?
The study of how often diseases occur in different groups of people and why.
