POB Lab Exam 2

Which of the following statements is true of DNA replication?

the replica strands are complementary to the templates

Which of the following statements is true about double-stranded DNA?

the strands run in opposite directions

How many of the letters (nucleotides) in a codon are needed to determine which amino acid it codes for?

three

Evidence of the Endosymbiotic Theory

1. Mitochondria and Chloroplasts have their own DNA 2. They are structurally similar to prokaryotic cells 3. able to reproduce themselves similarly to prokaryotic cells

Cell Theory

1. all organisms are made of cells 2. cells are the basic units of all organisms 3. all cells come from pre-existing cells

Molecules that cross the membrane more easily:

small non polar soluble in lipids

Which of the following could be the independent variable in the student designed household chemical experiment in Lab 4?

Chemical Solution

Eukaryotic Cells

Contain a nucleus and other organelles that are bound by membranes Plants, Fungi, Animals

Which of the household substances that you tested were acidic?

soda sports drink

Pop beads were used to model _____.

DNA and RNA molecules

Osmosis

Diffusion of water through a selectively permeable membrane (passive transport)

T or F: Mixed bacteria slides should be placed in bleach after use to avoid pathogen transfer.

False

T or F: Several drops of each stain should be added to each blank slide before applying a specimen. After the specimen is added, distilled water should be added to dilute the stain before adding a cover slip.

False

T or F: Water placed in a beaker does not require a label.

False

T or F: When beta cyanin was released from the beet cells due to damage caused by temperature changes, it could be returned to the cells by returning cells to the original temperature.

False

T or F: You must draw everything you see in your field of view.

False

T or F: You will loose points if you get any liquid stains on your lenses.

False

Which of the following slides from Lab 3 were not considered safe to clean and reuse after viewing?

Human cheek cell

Just imagine for a moment that NASA's Curiosity Rover that landed on Mars in the summer of 2012 found evidence of life at the cellular level on Mars. Imagine that their initial observations show that this Martian cell has a nucleoid region and also a cell wall, and measures 7 microns in diameter. What can you conclude about this cell? Check all that apply.

It is a prokaryote It shares characteristics with cells on earth

The cells of a person with adrenoleukodystrophy (ALD) swell with a buildup of fatty acids. In other words, fatty acids are not being broken down. Which organelle is most likely failing to function correctly?

Lysosome

Active Transport

Movement through protein channels by use of energy

Using your knowledge of cell membrane structure and the results you obtained in Lab 3 on cell structure, pretend you are looking at the cell membrane of a beet, Beta vulagaris, under the microscope. What would you expect to see if you stained the beet cell with Methylene blue?

Negatively charged particles such as DNA, cell membranes, and some proteins would stain blue.

Diffusion does not require the cell to expend ATP. Therefore, diffusion is considered a type of _____.

Passive Transport

Which of these best describes how the mixed bacteria slides appeared when viewed on your own microscope at your table in Lab 3? -ink fuzz without much detail -well defined individual bacterial cells of the three different shapes -green bubbles circulating in a current -bricks in a wall

Pink fuzz without much detail

Which of the following structures(s) is/are found in prokaryotic cells? ribosomes endoplasmic reticulum nucleus mitochondria

Ribosomes

Which type of stressor will be used to potentially damage beet cell membranes in the first experiment?

Temperature

How would the shape of a DNA molecule change if adenine paired with guanine and cytosine paired with thymine?

The DNA molecule would have irregular widths along its length.

Onion and potato are both underground structures for plants. What is their function?

To store energy for later use

Which type of mutagen did we use to potentially mutate our study organism?

UV light

The structure of the cell membrane is often referred to as

a 3D fluid mosaic

In DNA Extraction and Isolation: what does the baking soda do?

acts as a buffer slows down the process

To prevent or decrease contamination, we used _____ technique for procedures in this lab.

aseptic

The center of the DNA molecule consists of _________________.

base pairs of nitrogenous bases

In DNA Extraction and Isolation: What does the soap do?

break down cell membrane

In DNA Extraction and Isolation: what does the meat tenderizer do?

breaks down protein

In DNA Extraction and Isolation: what does the ethanol do?

caused DNA to precipitate out of solution

Prokaryotic Cells

do not have a nucleus or other membrane-bound organelles Bacteria and Archaea

selectively permeable

some substances cross more easily than others

Stressors that can affect cell membranes

extreme temperatures extreme pH harsh chemicals detergents organic solvents

T or F: Petri dishes used in lab will be sealed closed and will not be opened again, even to collect results.

false

T or F: The UV light used in lab is only strong enough to damage microbes; it will have not affect students.

false

Cell Membrane function

functions as a barrier between the inside and outside of the cell and controls the movement of substances into and out of the cell.

Phospholipids have a _____ head and a _____ tail.

hydrophilic head hydrophobic tail

membrane considered a mosaic because

its components are pieced together from many different types of proteins embedded in the phospholipid bilayer

Cell membranes consist mostly of...

lipids

denaturation

loss of normal shape of a protein due to heat or other factor

Endosymbiotic Theory

mitochondria and chloroplasts derived from prokaryotes that were taken up by a larger cell

Passive Transport

movement through protein channels without requiring energy

Pyrimidines are made up of ______________ ring(s) of carbon.

one

The plasma membrane is selectively permeable. Which of the following can pass freely through the membrane with no assistance?

oxygen and carbon dioxide

Larger, charged molecules move by

protein channels

When staining with Iodine

reacts with starch to produce a blue black color in the cell

The phospholipid bilayer makes the membrane _____ ______

selectively permeable

When staining with methylene blue

stains negatively-charged particles in the cell (DNA, RNA, proteins)

Why was the light transmittance reading for the frozen beet cylinder so low? Check all that apply.

water expands as it freezes, breaking the cell membrane. water forms crystals as it freezes which poke holes in the cell membrane