BIO 105 Exam 2

SARS-CoV-2

new form of coronavirus

SARS

sudden acute respiratory syndrome

What is the relationship between COVID-19 and SARS-CoV-2

COVID-19 is the DISEASE caused by the VIRUS SARS-Co-V-2 (just like AIDS is to HIV)

What does COVID-19 stand for?

Corona Virus Disease 2019

What does SARS-CoV-2 stand for?

Severe Acute Respiratory Syndrome Coronavirus 2

virus

noncellular (need a host cell). obligate parasites of our cells

How do viruses reproduce?

find a host cell and then hijack the metabolic machinery of the cell to produce more copies (use host cell to produce genetic material)

Which of the following would not be found in a virus?


1. DNA or RNA
2. Exterior envelope
3. Capsid
4. Nucleus

Nucleus

What is COVID 19?


1. The virus that causes SARS-CoV-2
2. The disease caused by SARS-CoV-2
3. The 19th coronavirus discovered
4. A bacterium

The disease caused by SARS-CoV-2

Which of the following is not true concerning the structure of a coronavirus?


1. It has a capsid made of proteins
2. DNA is its genetic material
3. It has an envelope surrounding the virus
4. The S proteins help the virus target specific host cells

DNA is its genetic material

A disease consistently found in a region is called?


1. Endemic
2. Epidemic
3. Outbreak
4. Pandemic

Endemic

An early study found that people with glasses were less likely to get COVID 19. Why might this be true?


1. People with glasses tend to wear mask
2. Glasses prevent droplets from landing on the eyes
3. Glasses restrict people from touching their eyes as much with contaminated hands
4. People with glasses are usually superhuman in disguise and can't catch COVID 19

Glasses restrict people from touching their eyes as much with contaminated hands

Which of the following organisms possess a form of coronavirus that is most similar genetically to the SARS-CoV-2 virus in humans?


1. Civets
2. Birds
3. Horseshoe bats
4. Pangolins

Horseshoe bats

Which of the following statements are true concerning evolution?


1. It is the unifying theme in the study of biology
2. It is the result of heritable changes in genetics
3. Individuals may evolve over time
4. It only occurs over long periods of time

It is the unifying theme in the study of biology AND It is the result of heritable changes in genetics

Which of the following statements is NOT correct regarding viral reproduction?


1. All viruses contain DNA as their genetic material 
2. Viruses target specific cells to be the host cells for reproduction
3. The envelope (in viruses that have one) is the remnants of the host cell's plasma membrane
4. In the lysosomic cycle, the virus delays reproduction

All viruses contain DNA as their genetic material

Which of the following is NOT correct regarding antigenic drift?


1. It is caused by two different viruses infecting the same host cell
2. Mutations may be introduced by the action of the RNA polymerase enzyme 
3. It may result in a reduced fidelity for flu vaccines

It is caused by two different viruses infecting the same host cell

Which of the following phases of COVID-19 produces the symptoms most commonly associated with the disease?


1. Pulmonary phase
2. Asymptomatic phase
3. Hyperinflammation phase

Pulmonary phase

Which of the following levels of biological organization represents the sum of all of the locations where life may be found on the planet?


1. The biosphere
2. An ecosystem 
3. A community 
4. Earth

The biosphere

The average temperature and precipitation of an area are referred to as it’s?


1. Climate
2. Biosphere
3. Community
4. None of the Above

Climate

Which of the following is not considered a greenhouse gas?


1. Carbon dioxide
2. Oxygen
3. Methane
4. Water vapor

Oxygen

Which of the following is NOT correct regarding the element of carbon?


1. It’s involved in the formation of organic molecules
2. It forms long chains called hydrocarbons
3. Its long term reservoir is living creatures
4. It is absorbed from the atmosphere via the process of photosynthesis in plants

Its long term reservoir is living creatures

Which of the following is NOT required for the formation of a fossil fuel?


1. Capture of social energy by autographs
2. Organic remains of plants and animals
3. Conversion of carbohydrates into a solid
4. High pressure

Conversion of carbohydrates into a solid

Most scientists have concluded that climate change has already caused which of the following at the individual and species levels?


1. Increased extinction rates
2. Increased temperature related deaths
3. Increased exposure to diseases from mosquito viruses
4. All of the above

All of the above

Which of the following is both fairly cold and also has low precipitation?


1. Savanna 
2. Taiga 
3. Deciduous Forest

Taiga

Which of the following is not always considered to be a clean form of alternative energy?


1. Wind
2. Nuclear power
3. Geothermal
4. Hydroelectric

Nuclear power

Which of the following forms of geoengineering proposes increasing the reflectivity of the planet so that more solar radiation is reflected back into space?


1. Genetic manipulation
2. SRM
3. CDR

SRM

ALL viruses have (?) and (?)

1. Genetic material (DNA or RNA)
2. Capsid (protein coat that surrounds genetic material to hold it

SOME viruses have…

**Envelope** that surrounds the capsid

* remnant of the plasma membrane of the host cell
* makes it harder for the body to recognize it as a virus
* assists in the attachment and entry of virus into host cell

Coronaviruses

group of related RNA viruses that infect avian and mammalian species

Coronavirus Structure

* enveloped
* single-stranded RNA molecule
* crown-like spikes emerging from surface of the virus

History of Coronaviruses in Humans…

severe SARS appeared in China in 2002

* origin in bats or civets
* spread to humans → caused REGIONAL epidemic in 2003

\
MERS-CoV appeared in Jordan in 2012

* origin in bats, spread to camels

\
SARS-CoV-2 appeared in Wuhan, China in 2019

Coronavirus structural proteins

four main structural proteins make up the **capsid** and **envelope**


1. Spike (S) glycoproteins
2. Envelope (E) glycoproteins
3. Membrane (M) glycoproteins
4. Nucleocapsid (N) proteins

What gives the coronavirus its name?

Spike proteins, look like crowns surrounding the virus

Zoonotic disease

disease transmitted from an animal host to humans

__% of all diseases in humans originated in animals other than humans

60%

Antigenic shift

occurs when two or more viral strains combine genetic material and a novel virus emerges

* new forms can be contributed to humans
* lives in one species for a while and then hurts the new species it jumps to

T/F: All zoonotic diseases are viruses

FALSE

Many zoonotic diseases are referred to as ___

**Emerging viruses** (have only recently been shown to infect large numbers of humans)

Coronavirus of horseshoe bats __% genetically similar to SARS-CoV-2; pangolin about _% similar

Horseshoe bats = 96%

Pangolin = 90%

Endemic

something that is consistently present in a population but limited to a specific geographical area

* often referred to as baseline/normal level of disease in a population

EX. the cold and flu

Outbreak

greater-than-anticipated increase in the number of **endemic** cases in a specific geographical area

* can be a single case in a new area
* if not quickly controlled, can become an **epidemic**

Epidemic

occurs if there’s an unexpected increase in the number of cases in a specific geographical area (greater spread over time)

Pandemic

disease that grows exponentially and moves between geographically distant populations (multiple areas)

SARS-CoV-2 are ___ viruses

airborne viruses

* infect cells of respiratory system

How does coronavirus spread?

**direct contact transmission** and **indirect transmission**

direct contact transmission

human-to-human transmission of virus happens through infectious respiratory droplets (coughing, sneezing, talking)

* virus can become aerosolized and travel distance up to 6 ft and remain in air for 3 hrs

indirect transmission

* virus can survive on surface for up to three days → person touches surface and then their own nose/mouth/eyes
* can eat this virus and not get infected
* classified as zoonotic virus → pets/wildlife may carry virus; BUT no indication pets can transmit to humans

\*\*washing hands reduces __rate of infection__ from a surface

genes

set of instructions within DNA

genome

sum of all genes in an organism

T/F: Viruses genetic material can only be made of RNA

FALSE, can be DNA or RNA

T/F: viruses are specific in the types of cells they infect

TRUE; depends on the function of the proteins of the capsid and what they’re coded to do

Two virus life cycles…

1. Lytic cycle (immediate)
2. lysogenic cycle (delayed)

Lytic Cycle

virus immediately begins using resources of host cell to manufacture new viruses

Lysogenic Cycle

virus integrates directly into host cell genome and delays reproduction until a later time (reproduces as the host cell reproduces because put its own genetic material into the cell)

How do RNA viruses prepare genetic material to reproduce in host cells

**Retroviruses** (HIV)

* RNA virus converts its own RNA into DNA to reproduce in host cell since __*host cells require DNA to start protein synthesis*__
* done by an enzyme called **reverse transcriptase**

\
**Other** (SARS-CoV-2)

* convert viral RNA genome into an mRNA molecule for translation

\
REGULAR: DNA → mRNA → protein

RETRO: RNA → DNA → mRNA → protein

OTHER: RNA → mRNA → protein

giant viruses

possess ability to manufacture their own proteins

* could be considered to be “alive”

T/F: viruses are considered “alive”

FALSE; rely on a host cell for processes that biologists use to determine if something is alive

T/F: evolution can happen at the individual level

FALSE

* POPULATIONS change over time, NOT individuals

evolution

* changes in population over time (could be quick OR slow)
* heritable changes in genetic information

Four things needed for evolution

1. VARIATION (individuals vary in their traits, differ in fitness)
2. COMPETITION (struggle for existence)
3. HERITABILITY (pass on traits)
4. TIME (can happen quick or slow, depends on generation time)

Three ways of variation selection in populations

1. stabilizing selection
2. directional selection
3. disruptive selection

Stabilizing Selection

favors most common form of the variant and selects against extreme variants (peak NARROWS)

EX. height remains about the same over time

Directional Selection

favor variants at one end of the distribution (peak SHIFTS left or right)

EX. get taller or shorter over time

Disruptive Selection

actively selects against the intermediate in a population, favoring both extremes of the spectrum (TWO peaks result)

EX. small and large turtles remain because medium ones eaten

Two methods in which SARS-CoV-2 evolve

1. **antigenic drift** - occurs when three are small changes in __surface spikes__ of virus (common as mutations when virus converts its own RNA into mRNA)

__EX__. alpha, beta, gamma, and omnicron variants
2. **antigenic shift** - two different forms of virus infect the same cell (worse than drift)

\--- host cell may manufacture particles from both viruses and reassemble them into a new variant

How does SARS-CoV-2 infect the body

viral particles enter body through respiratory system and travel down into small air sacs called **alveoli**

virus then enters and hijacks **ACE-2** receptors on epithelial cells

Three Phases of COVID-19

1. **asymptomatic phase**


1. can still spread
2. virus incubates 4-5 days
3. some infected may not pass this stage
2. **pulmonary phase**


1. immune system begins full response to virus
2. symptoms appear
3. 80% don’t pass this phase
3. **hyperinflammation phase**


1. develop Acute Respiratory Distress Syndrome (ARDS)
2. Often require additional oxygen and potentially ventilation (low O2 levels)
3. Additional organ damage may occur due to a **cytokine storm**

T/F: vaccination is the most effective way of preventing COVID-19

TRUE

How does the flu vaccine work?

individual is exposed to an **antigen**, body then begins an immune response against **antigen** creating **memory T** and **B cells**

* body will now respond faster when exposed again

How does the mRNA vaccine for COVID-19 work?

use the **mRNA of the S protein** as an **antigen**; body of the individual with the vaccine now produces its own harmless mRNA

* mRNA vaccines use your OWN body’s machinery to make bits that prime the body (fast!!!) (effective!!!)

T/F: Vaccines prime your body to recognize viruses

TRUE

antigen

something that evokes an immune response

COVID-19 treatments

paxlovid (attack life cycle of virus and don’t prevent infection) & monoclonal antibodies

NOT TREATMENTS: hydroxychloroquine (antimalarial), ivermectine (treat worms)

T/F: Climate change and global warming are the same

FALSE

T/F: Extreme weather is always hot

FALSE; **climate extremism** (there are weather extremes in both directions, cold and hot)

___ of climate change is relatively indisputable and agreed upon by most scientists

SCIENCE of climate change

The understanding of climate change (?) political; what we DO about climate change (?) political

understanding IS NOT political

what we do IS political

climate

average weather patterns (temperature AND precipitation) in an area over time

biosphere

sum of locations where life exists on Earth

global warming

trend in Earth getting gradually warmer → increases in __surface__ __temperature__

T/F: all extreme weather events are connected to climate change

FALSE; events like hurricanes/tornadoes still being investigated -- BUT we do know that it is linked to __extreme precipitation__ and __heat waves__

greenhouse gases

gases in the atmosphere that trap heat near Earth’s surface

* H2O (vapor), CO2, CH4, N2O, O3, CFCs

greenhouse effect

phenomenon in which greenhouse gases retain heat in the lower atmosphere

Carbon Dioxide

* ability to __absorb infrared energy__
* one of the most important greenhouse gases
* much storage of CO2 in oceanic plants

Methane

* rare gas in atmosphere
* captures and releases 30 TIMES the amount of heat as CO2
* unstable; only remains in atmosphere for about a decade

Evidence of Climate Change from Oceans

when CO2 enters the oceans, it produces **carbonic acids** which leads to **ocean acidification**

* negative impacts on shellfish (soften shells), bleaching of coral reefs, etc.

T/F: there is a DIRECT relationship between atmospheric CO2 concentrations and global temperatures

TRUE

\*\*\*\***CO2 levels fluctuate every 6 months**, trees take in much CO2 in the __summer__, and then when shedding leaves in the __winter__, that CO2 is released back into the atmosphere (specifically in northern hemisphere)

organic molecule

contains both carbon and hydrogen

hydrocarbons

long carbon chains, studied in organic chemistry

carbon sinks

major reservoirs for carbon

* oceans -- BIGGEST!
* underground in fossil fuels
* atmosphere

carbon source

living organisms release CO2 into atmosphere through the process of **cellular respiration** during the breakdown of organic materials for energy

living organisms = carbon (?) and then carbon goes into carbon (?)

carbon sources; carbon reservoirs

Carbon Cycle

carbon naturally cycles between nonliving geologic and atmospheric reservoirs, called sinks, and living organisms

autotrophs

organisms that make their own foodpho

photosynthesis

process through which plans make carbohydrates from CO2, water, and sunlight

* occurs in **chloroplasts**
* water + sunlight + CO2 → sugar + H2O

Evolution of Cellular Organelles to MITOCHONDRIA and CHLOROPLASTS

Primitive eukaryotic cell consumed an **aerobic bacteria** and turned it into functioning part of the cell (**mitochondria**)

\
Second event where cell consumed **photosynthetic bacteria** that became **chloroplasts**

T/F: both chloroplasts and mitochondria have their OWN DNA because each were once their own thing before becoming a part of the eukaryotic cell

TRUE; previously aerobic bacteria (mito) and photosynthetic bacteria (chloro) before evolution into organelle

fossil fuels

fuel source that has been formed within the Earth from plant/animal remains

Fossil Fuel Political Issue…

* industrialized nations have slightly reduced CO2 output, but developing nations have dramatically increased
* industrialized nations want developing nations to slow their output BUT that would hurt their economies
* US has largest cumulative release of CO2 since 1750 (esp from when US super industrialized)

vector (& significance due to climate change)

something that moves an infectious agent (bacteria/virus) from one organism to another

\*\*as climates become warmer and warmer, vectors have a greater geographical territory they can spread into