Biology Lab midterm 2/2

Being biologically literate enables individuals to

(i) use the process of scientific inquiry to think creatively about real world issues that have biological components, (ii) communicate these thoughts to others, and (iii) integrate these ideas into decision-making.

While at the 40x objective, adjust the position of the slide so that the entire view is filled with cells (the red line should not be visible), select a line around the center of the view. About how many cells can you count from top to bottom of the view?

10

When examining a section of skeletal muscle tissue under a compound light microscope, you want to increase the magnification in order to see the striations of the cells. You decide to increase the magnification by changing from the 10X objective lens to the 40X objective lens. By what magnitude is the true magnification increased by changing from the 10X to the 40X objective lens?

300x

with the "e" activity, The correct description of what you see is

A rotated and upside down e resembling a lowercase "a"

What is the appearance of skeletal muscle?

Cells are long and cylindrical. Each fiber shows periodic light and dark bands called striations. The individual cells are separated from each other by a very thin layer of connective tissue.

what is the appearance of a typical plant leaf cell?

Cells are round or oval. These cells were taken from an area of the leaf called the mesophyll. The small dark-stained ovals are the chloroplasts. Due to the staining technique used, the nucleus is not clearly displayed. The vacuole appears clear, although some of the vacuoles appear to have something inside.

in onion root cells, The slide you are viewing at 40x is showing

Cells that are mainly rectangular shaped with a large nucleus in the center

What organelle is responsible for photosynthesis?

Chloroplast

The three domains of life include

Bacteria, Archaea, and Eukarya.

What does it mean to be isotonic?

The extracellular fluid has the same osmolarity as the cell, iso means the same, no movement of water

Ocular lenses.

The eyepiece sits above the ocular lens; this is the part you look into to view your specimen. The ocular lenses are set at 10x magnification and cannot be changed, but the distance between the two eyepieces, or intraocular distance, is adjustable to match the distance between your eyes. To clean the lenses of dust or debris, use lens paper

Compare the red blood cells placed in 10% salt solution to the Elodea under the same conditions. How did the cells change? Did they change in the same way? What accounts for any difference you observed?

The red blood cells placed in 10% salt solution were hypertonic, meaning the extracellular fluid has a higher water concentration than the fluid within the cell. This indicates that water is exiting the cell. This also can mean that they are shrinking. They changed from having an isotonic tonicity with the 9% salt solution to being hypertonic. When they were isotonic, there was no net movement because the extracellular fluid has the same water concentration as inside the cell. The Elodea placed in 10% salt solution were also hypertonic. However, they were hypotonic under the 9% solution. This means that the extracellular fluid had a lower concentration than the fluid inside the cell, indicating the water is entering the cell. This shows that the red blood cells and the Elodea changed in different ways.

Mechanical Stage.

The mechanical stage is the specific area where the slide is secured to the stage. It is typically metal with a sliding arm on one side and a fixed metal holder on the other side. A mechanical stage is also equipped with stage clips to hold the slide in place, and adjustment knobs to move the stage horizontally—side to side—and toward and away from you.

Stage.

The stage is the placement area for the specimen slide. It can be moved vertically up and down by turning the coarse adjustment knob and the fine adjustment knob.

Condenser.

This contains a system of lenses that focuses light on the object placed on the stage. Condensers can be either movable or fixed. A movable condenser will have a knob that allows for the up and down adjustment of the condenser. Fixed condensers have their illumination set at the factory and cannot be adjusted. Unfortunately, the factory setting is only an approximation, and over time becomes progressively misaligned. For this reason, an adjustable condenser is preferred

What is the function of chloroplasts?

To make food through photosynthesis, and contains chlorophyll

What is the main function of the nucleus?

To store and protect DNA

whereas the movement for the main stage is usually _______ .

UP AND DOWN

If nothing happened to the Daphnia, provide a possible explanation.

We didn't see anything happening when looking at daphnia under the different solutions. A possible explanation is because it was undergoing osmoregulation. Osmoregulation is the process of regulating the water and electrolytic balance to maintain homeostasis. Regardless of changes to its environment, osmoregulation helps maintain an internal balance.

The compound light microscope has two kinds of stages. The movement for the mechanical stage is usually

SIDE TO SIDE

Many of the multicellular organisms have cells that perform specific functions that support the organism as a whole.

Single-celled organisms, on the other hand, must perform all cellular functions independently in order to sustain life.

What is osmotic lysis?

The bursting of a cell membrane due to osmotic movement of water into the cell when the cell is in a hypotonic environment

cell requires energy to move a substance against its concentration gradient

active transport

Lysosomes perform

digestive functions, acting as the repository for old organelles and some wastes.

Tertiary literature

does not usually reference primary literature. Examples: science magazines, newsletters, science articles in newspapers, and introductory textbooks.

The simplest example of a microscope is a

double convex lens used as a magnifying glass.

Vacuoles

another type of storage organelle that are easily viewed in plants under the microscope. -Depending on the needs of the plant, it may store sugar, water, pigments, or toxins

All eukaryotic cells

are enclosed by a plasma membrane and possess a membrane-bound nucleus, various organelles, an endomembrane system, and a cytoskeleton.

Cilia

are hair-like projections of the cell membrane In many cells they function by beating back and forth.

When transporting the microscope or carrying it across a room, you should hold it by the _________ and ___________.

arm and base

biology is an enormous field of science that requires many subdisciplines. The different subdisciplines are collectively called the

biological sciences.

It is easy to associate mitochondria with animal cells,

but plants also have mitochondria, as well as chloroplasts.

While many bacteria do not have a capsule, almost all have a

cell wall, which provides an additional layer of protection for the bacterial cell and prevents dehydration

in onion root cells, The best description for how the cells are arranged on the slide you are viewing is

cells are connected to one another, arranged in vertical (top to bottom) columns

In the human body, sperm cells are the only type of cells that contain _________, which is a cellular structure involved in motion.

flagellum

what kind of environment do paramecium live in?

fresh water environments

In the multicellular organism, the cilia

function to move debris or mucus from the cell's surface.

The cytoskeleton is a system of protein filaments and tubules that

functions as a scaffolding to provide shape, support, and organization of the cell and its components. It functions as transportation routes for the large internal structures to move within the cell and plays an important role in cellular division.

Biological literacy can be defined as

general, fact-based understanding of the basics of biology.

Microvilli

generally smaller than cilia. As a projection of the membrane, they provide additional surface area for absorption or secretion of substances.

The impact factor system is used for primary literature to

grade the importance of a journal, and should be considered when reviewing literature.

A Paramecium, like the one pictured here must continuously use its contractile vacuole to expel excess water from its cell in order to survive. This means that the Paramecium's natural environment (extra cellular fluid) is

hypotonic

Coarse adjustment is used for

initial focusing of specimens at low power.

The cytoplasm contains a greater concentration of solutes than its surroundings and so

it absorbs water by osmosis. The excess water is collected into a specialized organelle called a contractile vacuole, which swells and finally expels water through an opening in the cell membrane.

What is passive transport?

it is a transport that does not require the cell to use energy and involves a substance diffusing down its concentration gradient across a membrane

some antibiotics target the cell wall of some bacteria and end up...

killing them indirectly through osmotic lysis

whip-like flagellum

looks like a long tail and moves in a seemingly erratic whip or propeller motion.

Primary literature is the

most technical type of scientific literature in which scientists write a "paper" describing an experiment(s) or field work they have conducted. These papers are generally submitted to and published in a peer-reviewed scientific journal.

For single-celled organisms, the cilia allow them to

move in every possible direction, and quickly.

In some single-celled organisms,

multiple flagella may be present.

Total magnification is determined by

multiplying the magnification of the objective by the magnification of the ocular lens.

What is osmosis?

net movement of water across a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration

Many students entering college have a

nominal to functional level of biological literacy in which they are able to identify terms and questions as biological in nature, define terms correctly, and memorize responses.

Uno and Bybee (1994) outline four levels of biological literacy:

nominal, functional, structural, and multidimensional.

Science is often divided into three branches:

physical sciences (physics, chemistry, etc.), earth sciences (geology, oceanography, etc.), and life sciences (botany, zoology, genetics, etc.).

Bacterial capsule, a structure of many bacteria, is a

polysaccharide layer that lies outside the cell and considered part of the outer envelope of a bacterial cell. A capsule provides protection to a bacterial cell and enables the cell to attach to surfaces in its environment.

There are different types of scientific literature, and they are generally referred to as

primary, secondary, tertiary, and grey literature.

What is the function of a ribosome?

protein synthesis

some cells have external structures that

protrude from the cell's surface.

Tertiary literature consists of work that

relies on primary and secondary literature. This literature is aimed at scientists who work in different areas from the subject matter of the publication, or towards an interested but non-scientific audience.

Two cellular components found in plant cells but not animal cells are

a cell wall and chloroplasts

There are several differences between plant and animal cells including

a cell wall that is found in plants and a variety of organelles and cellular structures that are unique to each either through their entire life or during just a part of the life span.

Secondary literature describes literature that

relies on primary literature for information. Examples: review articles, textbooks, handbooks, and manuals. does not have to be written using the same formatting as primary literature, BUT it must be fully referenced and most of these references must be to primary literature.

For multicellular organisms, it is typically present in the

reproductive stage of the organism

The specific cell component where proteins are made/synthesized is

ribosomes, which are too small to be visible within the muscle cell under a microscope

The endomembrane system

s a network of membranes that connects organelles and allows them to function cooperatively, such as the membrane of the endoplasmic reticulum, Golgi apparatus, and vesicles such as lysosomes.

Often a microscope nosepiece will have three or four different objective lenses:

scanning objective (4x-5x magnification), low-power objective (10x-20x magnification), high-power objective (40x-50x magnification), and oil-immersion objective (60x-100x magnification).

. One of the important characteristics of the cell membrane is its

selective permeability—only certain molecules are permitted to move across the membrane. Therefore, cells are able to regulate the substances that move across the cell membrane and across membranes of the cellular organelles.

When a substance such as sugar dissolves in another such as water the result is a solution. In this example, sugar which is the dissolving substance is referred to as a

solute

...whereas the water is referred to as the

solvent

What is tonicity?

the ability of an extracellular solution to make water move into or out of a cell by osmosis

Within the objective, there is a second lens which is responsible for the resolving power:

the ability to reveal detail; to distinguish two closely-spaced objects as being two rather than one.

The smaller the distance between two objects that can be distinguished from one another,

the better is the resolving power of the instrument used to view the objects.

All types of scientific literature can be found on the internet, and this is often problematic for the general public as well as trained scientists because

there are many sites on the internet that appear very formal and trustworthy, but they present misleading information while some sites that appear very simple present high-quality unbiased information.

What are carrier proteins?

they change their shape to move a target molecule from one side of a membrane to another

Some cilia don't move at all;

they have a sensory function instead.

What are channel proteins?

they span the membrane and make hydrophilic tunnels across it, allowing their target molecules to pass through by diffusion

The ability to understand terminology and complex processes across many subdisciplines begins with

the idea of biological literacy.

What is concentration gradient?

the region of space over which the concentration of a substance changes, and substances will naturally move down their gradients, from an area of higher to an area of lower concentration

What is osmolarity?

the total concentration of all solutes in the solution •Example: low osmolarity would have fewer solute particles in the solution

In the cross section of the leaf, chloroplasts are..

concentrated near the top, this would optimize the capturing of light for photosynthesis

multidimensional level, in which students understand

conceptual schemes of biology, can explain biological concepts in their own words, and understand the interactions between biology and society.

these vesicles..

contain a highly acidic environment and digestive enzymes; the combination of the two agents break down various particles.

eukaryotic cells

(1) are usually larger than prokaryotic cells, (2) contain membrane-bound organelles, which compartmentalize the internal structures of the cells, and (3) possess a nucleus.

If you were observing a specimen (object) using the oil-immersion objective, your total magnification would most likely be

1000X

Which objective lens made it possible to view individual capsules?

100x (oil immersion)

The magnification for the ocular lens is

10X

Match the magnifications on the left with the correct name for the lens

10X - 20X Low-power objective 40X - 50X High -power objective 4X - 5X scanning objective 60X - 100X Oil-immersion objective

Viewing the video of the Paramecium, look for the contractile vacuoles. How many contractile vacuoles function within the paramecium?

2

Diaphragm.

Also referred to as the iris diaphragm, it is used to adjust the amount of light striking the specimen on the slide. It can be opened or closed using the lever on the side of the condenser. Proper use of the diaphragm can dramatically increase the contrast of the image.

The Elodea cells are large and you will be able to observe cytoplasmic streaming, particularly in the specimens with 0.9% saline solution. What is cytoplasmic streaming? Describe it.

Cytoplasmic streaming is the movement of cytoplasm through plant cells, animal cells, and bacteria. This is important because it helps transport organelles, proteins, and nutrients throughout cells. When we looked through the microscope, we were able to see the rotational movement of the cytoplasm within each individual cell. This flow is caused by forces from the cytoskeleton, the network of protein fibers that maintain the shape of the cell.

What is diffusion?

Diffusion occurs when a substance tends to move from high areas of concentration to low areas of concentration until its concentration becomes equal across space.

Eukaryotic cells differ from prokaryotic cells in a number of ways. Which statement about these differences in NOT CORRECT?

Eukaryotic cells have a plasma membrane while prokaryotic do not

Plants and animals belong to the domain

Eukarya

which are correct?

Eukaryotic cells are usually larger than prokaryotic Eukaryotic cells have membrane-bound organelles while prokaryotic do not Eukaryotic cells have a nucleus while prokaryotic do not

Which part of the compound light microscope is used to adjust the amount of light striking the specimen being viewed?

The diaphragm

Describe the action of the contractile vacuoles

I could see the contractile vacuoles swelling and then contracting. They are expelling excess water within the cell while making this motion.

.. The amount of a solute that occurs in a solution is described as

tonicity or osmolarity

The bacterial capsule as "viewed" through the microscope on this slide can be described as

Light colored oval shapes with a dark center

What are the structural differences between plant and animal cells?

One of the main structural differences between animal and plant cells is that plant cells have chloroplasts and a cell wall. Animal cells produce energy from food in the mitochondria, but plant cells perform photosynthesis with their chloroplasts. Although animal cells lack a cell wall, they have a plasma membrane for structural support and protection. Also, the nucleus is in the middle of animal cells, but it lies on the side of a plant cell. Another difference is that plant cells usually have at least one large vacuole, while animal cells have smaller vacuoles, if any at all.

Define osmoregulation.

Osmoregulation is the process of maintaining the osmotic balance across membranes within the body by the control of salt and water concentrations.

Why do you think the "e" appears the way it does?

The "e" appears the way it does because the light rays of the "e" cross before reaching our eye. The compound microscope uses two types of lenses, the objective lens and the ocular lens. Both are convex lenses, making them curved outward. This causes the light rays to cross upon the focal point and the "e" to appear reversed.

Which solution was considered hypertonic in your experiment? What effect would this solution have on the function of the red blood cells in the body?

The 10% solution was considered hypertonic in our experiment. A red blood cell will lose water and shrivel up when placed in this hypertonic solution. This is because the water diffuses out of the cell by osmosis, decreasing the volume of the cytoplasm.

If a disease affected a Paramecium's contractile vacuoles, stopping the normal functioning of the vacuoles, what would happen to the Paramecium under normal freshwater conditions?

The Paramecium would not be able to get rid of excess water so the cell would burst.

At the end of winter, water containing very high concentrations of road salt used to de-ice roadways runs off and some of it enters a very small freshwater pond that contains many aquatic organisms including Paramecium. What do you suppose will happen to the Paramecium?

The Paramecium's environment will become hypertonic causing Paramecium cells to shrivel

Objective lenses.

The objective lenses are mounted on a revolving nosepiece. Each objective contains a complex lens system. Magnification is determined by the first lens within the objective that is positioned closest to the specimen. The magnification is indicated on the side of the objective.

Base and arm.

These are the support parts of the microscope. They allow for easy carrying and stability during use

Which of the following is true of eukaryotes?

They are usually larger than prokaryotes They contain a nucleus They contain membrane bound organelles ALL OF THE ABOVE

Light source

This is built into the base with a lens that focuses light onto the condenser underneath the stage.

What is the contractile vacuole?

excess water is collected here, it swells, and it expels water through an opening in the cell membrane •Happens in paramecium when it lives in fresh water and the cytoplasm has a greater concentration of solutes

Always start with the highest power objective when using the microscope

false

The nucleus is a storage organelle for the cell.

false

What is plasmolysis?

in plants cells under hypertonic conditions, the cell membrane may detach from the wall and constrict the cytoplasm. This could happen if the plant is not watered

Grey literature

includes scientific information that is not published in the usual manner (as listed above). ex: theses, dissertations, published work with limited distribution, and conference proceedings. may be scientifically accurate; however, it is generally not accessed easily.

As with all eukaryotic cells, Paramecium possess a

membrane-bound nucleus, various organelles, an endomembrane system, and a cytoskeleton

We refer to the solution in reference to the

the cell, not the cell compared to the solution

What does it mean to be hypertonic?

the extracellular fluid has a higher osmolarity than the fluid inside the cell, hyper means more than, the water will be moving out of the cell

What does it mean to be hypotonic?

the extracellular fluid has lower osmolarity than the fluid inside the cell, hypo means less than, the net flow of water will be into the cell

remember in osmosis, only water can move across

the membrane, not the solute

The nucleus contains

the nuclear genome, which represents most of the genetic information found within the eukaryotic cells (recall that both mitochondria and chloroplasts also contain genetic information).

Using the 40X objective to view the cheek cells, what were you able to see?

the nucleus but not the other organelles

What is selective permeability?

the property of a cell (plasma) membrane in which some substances are allowed to move across the membrane (enter or leave) easily while others are not.

Cells on the intestines of animals need to stay connected to ensure that the contents of the intestines do not leak out. Cells stay connected by attaching to adjacent cells by way of proteins categorized as cellular junctions. Intestinal cells are connected by

tight junctions, which form a watertight seal between two adjacent animal cells, and by

Generally, all papers will include the following:

title, abstract, introduction, methods and materials, results, discussion, and conclusion.

Not all eukaryotic cells contain the same number or the same type of membrane-bound organelles.

true

Fine adjustment makes

very slight changes, allowing precise focusing at higher power.

What is facilitated diffusion?

when molecules diffuse across the plasma membrane with assistance from membrane proteins, such as channels and carriers

desmosomes

which act like spot welds between adjacent cells.