Bio 1011 labs 1-3 quiz

What is microscopy?

→ Using microscopes to view objects too small to see clearly with the naked eye.

What is magnification?

→ How much larger an object appears.

What is resolution?

→ Ability to distinguish two close objects as separate.

What is the ocular lens?

Eyepiece you look through; usually 10×.

What are objective lenses?

Lenses near the specimen that provide different magnifications.

What is the scanning objective?

4× objective; used to initially find the specimen.

What is the low-power objective?

→ Usually 10×.

What is the high-power objective?

→ Usually 40×.

What is the oil-immersion objective?

→ Usually 100×; used with immersion oil when applicable.

What is the revolving nosepiece?

→ Holds and rotates the objective lenses.

What is the stage?

→ Platform that holds the slide.

What are stage clips/mechanical stage?

→ Hold and move the slide.

What is the illuminator?

→ Light source.

What is the condenser?

→ Concentrates/focuses light onto the specimen.

What is the iris diaphragm?

→ Controls the amount of light passing through the specimen.

What does the coarse adjustment knob do?

→ Makes large focusing movements.

When should coarse adjustment be used?

→ At low power, especially when first focusing.

What does the fine adjustment knob do?

→ Makes small movements to sharpen focus.

What adjustment should you use at high power?

→ Fine adjustment.

Why shouldn't you use coarse adjustment at high power?

→ The objective could hit/damage the slide.

What objective should you start with?

→ Lowest-power/scanning objective.

How do you calculate total magnification?

→ Ocular × objective.

10× ocular × 4× objective

→ 40× total.

10× ocular × 10× objective

→ 100× total.

10× ocular × 40× objective

→ 400× total.

10× ocular × 100× objective

→ 1000× total.

What is field of view?

→ Area visible through the microscope.

Magnification ↑

field of view? → Decreases ↓

Magnification ↓

field of view? → Increases ↑

Magnification ↑

amount of specimen visible? → Decreases.

What is working distance?

→ Distance between the objective lens and specimen.

How does a compound microscope affect the image?

→ Image appears inverted/reversed relative to the specimen.

Move slide right, Image appears to move?

Left.

Move slide up → image appears to move?

→ Down.

What is a wet mount?

→ Specimen placed in liquid on a slide and covered with a coverslip.

What is a coverslip?

→ Specimen placed in liquid on a slide and covered with a coverslip.

What is evolution?

→ Change in inherited characteristics of a population over generations.

What is natural selection?

→ Individuals with advantageous inherited traits tend to reproduce more, causing those traits to become more common.

Who evolves: individuals or populations?

→ Populations.

Can an individual evolve during its lifetime?

no

What is variation?

→ Differences in traits among individuals in a population.

Why is variation important?

→ Natural selection requires differences for the environment to act upon.

What is an adaptation?

→ Inherited trait that improves reproductive success in a particular environment.

What is fitness?

→ Reproductive success.

Does "fittest" mean strongest?

→ No. It means most reproductively successful in that environment.

What is selection pressure?

→ Environmental factor affecting survival and reproduction.

Examples of selection pressures

→ Food, predators, competition, climate, disease, environment.

What is competition?

→ Organisms competing for limited resources.

What is a population?

→ Members of the same species living in the same area.

What is a trait?

→ A characteristic of an organism.

What is a heritable trait?

→ Trait that can be genetically passed from parent to offspring.

What did the different utensils in lab 2 represent?

→ Different traits/feeding structures.

What did the beans in lab 2 represent?

→ Food/resources.

What did the different terrains represent in lab 2?

→ Different environments.

What did collecting beans in lab 2 represent?

→ Ability to obtain resources needed for survival/reproduction.

What did collecting more beans in lab 2 suggest?

→ Greater success/fitness in that particular environment.

Why didn't every utensil collect the same number of beans?

→ Different traits performed differently in the environment.

Why could the best utensil change when terrain changed?

→ Different environments favor different traits.

Is one trait always the best?

→ No. Its advantage depends on the environment.

What happens to an advantageous heritable trait over generations?

→ It tends to become more common.

What happens to a disadvantageous trait?

→ It may become less common if its carriers reproduce less.

Does the environment intentionally create useful traits?

no

Do organisms evolve traits because they "need" them?

no

Where do differences come from?

→ Existing genetic variation, ultimately generated by processes such as mutation and recombination.

What does natural selection act on?

→ Heritable variation among individuals.

Natural selection changes what over generations?

→ Frequencies of inherited traits/alleles in a population.

What happens if the environment changes?

→ Which traits are advantageous may also change.

Natural genetic variation sequence

Step 1 → Individuals have variation.
Step 2 → Some variation is heritable.

Step 3 → Organisms face environmental pressures/limited resources.

Step 4 → Some traits lead to greater reproductive success.

Step 5 → Those traits are passed on more often.

Step 6 → Over generations, those traits become more common.

What is taxonomy?

→ Science of naming and classifying organisms.

What is classification?

→ Organizing organisms into groups based on shared characteristics/relationships.

Taxonomic order from broadest to most specific

Domain → Kingdom → Phylum → Class → Order → Family → Genus —> species

Mnemonic for taxonomy

Dear King Philip Came Over For Good Soup.

Broadest taxonomic category

→ Domain.

Most specific taxonomic category

→ Species.

Domain → Species: groups become…

→ Smaller and more specific.

Domain → Species: organisms become…

→ More closely related/similar.

Species → Domain: groups become…

→ Larger and more diverse.

Which indicates a closer relationship: same genus or same family?

Same genus.

Which indicates a closer relationship: same family or same order?

→ Same family.

What are the three domains of life?

→ Bacteria, Archaea, Eukarya.

Bacteria are…

→ Prokaryotes.

Archaea are

→ Prokaryotes.

Eukarya are…

→ Eukaryotes.

What is a prokaryotic cell?

→ Cell without a nucleus or membrane-bound organelles.

What is a eukaryotic cell?

→ Cell with a nucleus and membrane-bound organelles.

Do bacteria have DNA?

yes

Where is bacterial DNA located?

→ Primarily in the nucleoid region rather than a nucleus.

Do bacteria have ribosomes?

→ Yes.

Do bacteria have a cell membrane?

→ Yes.

Are bacteria usually unicellular or multicellular?

→ Unicellular.

Bacteria vs. Archaea

→ Both are prokaryotic but are different domains with important genetic/biochemical differences.

Coccus (cocci)

→ Spherical/round bacteria.

Bacillus (bacilli)

→ Rod-shaped bacteria.

Spirillum/spirilla

→ Spiral-shaped bacteria.

Vibrio →

Curved/comma-shaped bacteria.