Chapter 4 Study Guide

What features of mitochondria are similar to bacteria? Select all that apply.

- Circular DNA similar to plasmids - Independent movement - Membrane-bound ribosomes Cellular machinery for photosynthesis

What features are a part of all cells? Select all that apply.

- Cytosol Nucleus - DNA - Plasma membrane - Ribosomes

Which structures occur only in eukaryotic cells? Select all that apply.

- Golgi bodies Ribosomes Vesicles - Endoplasmic reticulum

What properties define the phospholipids that make up the lipid bilayer? Select all that apply.

- Nonpolar, hydrophobic hydrocarbon tails - Polar, hydrophilic phosphate heads

What is a microfilament?

A cytoskeletal element made of actin that reinforces cell membranes and functions in cell movement

Motor proteins, fueled by ____, move cellular cargo along tracks of ____.

ATP; microtubules and microfilaments

There are ____ microorganisms living in or on the human body as there are body cells.

About the same number of

Fluorescent dyes help visualize internal cellular structures by ____.

Absorbing UV light and emitting colored light

According to the cell theory, ____.

All living organisms are made up of one or more cells

The extracellular matrix in animal cells that supports and organizes tissues and plays roles in cell signaling is known as the ____.

Basement membrane

Which of these structures is not an example of an extracellular matrix?

Basement membrane - Nuclear envelope Cuticle Cell wall

Many species of bacteria live bound together by a glue-like substance that, among other things, makes up the plaque on human teeth. This is an example of a ____.

Biofilm

Fluid-filled sacs that may store amino acids, sugars, toxins, and ions in plant cells are called ____.

Central vacuoles

Which structure is large enough to be visualized with a light microscope?

Chloroplast

In plant and some protist cells, photosynthesis takes place in ____.

Chloroplasts

Pigments, other than chlorophylls, are synthesized and stored in ____.

Chromoplasts

Short hair-like structures that protrude from the plasma membrane of some eukaryotic cells are called ____.

Cilia

To visualize objects smaller than those that can be resolved by a light microscope, a(n) ____ microscope is used.

Electron

Lipids and proteins are synthesized in the ____.

Endomembrane system

Which of the following is a property of life that viruses lack?

Engages in self-sustaining biological processes such as homeostasis and metabolism

If free phospholipids were swirled into water, they would ____.

Form a lipid bilayer sheets or bubbles, with the hydrophobic tails facing each other

Which type of junction uses closable channels to connect the cytoplasm of adjoining animal cells?

Gap junctions

Substances targeted for export from the cell are modified and packaged in the ____.

Golgi bodies

All cells ____.

Have cytoplasm enclosed by a plasma membrane

Mitochondria ____.

Have their own DNA and ribosomes and divide independently of the cell

Most of the E. coli strains that reside in the human digestive tract ____.

Help with digestion, produce vitamins, and prevent the growth of pathogens

Phospholipid fatty acid tails spontaneously cluster together away from the aqueous cellular interior and exterior environment due to their ____ nature.

Hydrophobic

What happens when a round cell expands in diameter?

It's volume increases faster than its surface area does.

Archaea have molecules with reactive side chains in their plasma membrane, so the tails of archaeal phospholipids form covalent bonds with one another. As a result, the plasma membrane is ____.

Less fluid

What are the tenets of cell theory? Select all that apply.

Living cells possess DNA contained within a nucleus. - Cells are individually alive and are the basic structural and functional units of life. - Every living organism consists of one or more cells. - All living cells arise by division of preexisting cells.

Which functions are carried out by smooth endoplasmic reticulum?

Makes phospholipids and stores calcium

Fibers known as ____ contain the protein actin and help to strengthen and change the shapes of eukaryotic cells.

Microfilaments

In pseudopods, elongating ____ cause lobes of cytoplasm to bulge outward, while ____ help to drag the plasma membrane along.

Microfilaments; motor proteins

Which cytoskeletal element separates the cell's duplicated DNA molecules during eukaryotic cell division?

Microtubules

Which organelle converts the energy stored in sugars to ATP by aerobic respiration?

Mitochondria

Which structure consists of two lipid bilayers folded together as a single membrane?

Nuclear envelope

Proteins embedded in the nuclear envelope that selectively allow substances to cross into and out of the nucleus form ____.

Nuclear pores

A dense, irregularly shaped region within the nucleus in which subunits of ribosomes are synthesized is called the ____.

Nucleolus

Plasmodesmata are ____.

Open channels that connect the cytoplasm of adjacent plant cells

Which of these cell junctions are open channels that connect the cytoplasm of adjoining plant cells?

Plasmodesmata

What is the general term for double-membrane organelles that function in photosynthesis, storage, or pigmentation in plant and algal cells?

Plastids

What distinguishes archaea from bacteria? Select all that apply.

Presence of a nucleoid - Cell wall composition Membrane enclosed organelles - Lack of an external capsule

Different cell membranes can have different functions depending on the____.

Proteins that are anchored to the membrane

Most archaeal cell walls consist of ____, while most bacterial cell walls consist of ____, a polymer of peptides and polysaccharides.

Proteins; peptidoglycan

Which membrane protein is responsible for binding hormones that can trigger changes in the cell's activity?

Receptor

What kind of membrane proteins trigger a change in cellular activity in response to a stimulus?

Receptor proteins

A biofilm allows the participating cells to ____.

Remain in a favorable location without being swept away

Which structure is the primary site for the production of polypeptide chains?

Ribosome

Polypeptide chains take on their tertiary structure and assemble with other polypeptide chains within the ____.

Rough endoplasmic reticulum

Which type of micrograph gives the most detailed image of the surface of a cell?

Scanning electron micrograph

Phospholipids that are destined for cell membranes are synthesized in the ____.

Smooth endoplasmic reticulum

What are components of the fluid mosaic model of the cell membrane?

The cell membrane is a lipid bilayer with molecules such as cholesterol and proteins embedded in it.

Nearly all eukaryotic cells have mitochondria, but the number varies by the type of cell and by the organism. In general, cells that have the highest demand for energy tend to have ____.

The most mitochondria

Given the constraints on cell size, how can eukaryotic cells be so much larger than prokaryotic cells?

The presence of membrane-bound organelles effectively increases the area across which substances can pass.

Which type of junction prevents fluid leakage between cells?

Tight junction

Why are cells stained prior to viewing with a light microscope?

To visualize transparent internal cellular structures

Which type of microscopy allows us to clearly view the internal contents of cell structures smaller than 200 nm?

Transmission electron microscopy

Membrane ____ proteins move specific substances across the membrane, typically by forming a channel.

Transport

What are the functions of the nuclear pores? Select all that apply.

Transport RNA from the cytoplasm to the nucleus for protein synthesis Transport proteins from the nucleus to the cytoplasm for RNA synthesis - Transport RNA from the nucleus to the cytoplasm for protein synthesis - Transport proteins from the cytoplasm to the nucleus for RNA synthesis

​A cell membrane that is selectively permeable ____.

​Allows only certain molecules to cross

​Bacteria and archaea were originally classified as prokaryotes because they ____; however, it is now known that archaea ____.

​Are single-celled and do not have nuclei; are more similar to eukaryotes

In response to low blood glucose levels, the pancreas produces the hormone glucagon. Glucagon functions by binding to molecules on the surface of liver cells, causing changes in cellular activity that lead to the release of glucose into the blood. The proteins to which glucagon binds are ____.​

​Receptor proteins