W4 Practice

In muscle contraction, ______ and myosin filaments slide across each other

actin

As described in this chapter's Investigating Life essay, some bacteria contain magnetosomes, which allow bacteria to

align with Earth's magnetic field

How do vesicles carrying proteins destined for secretion move to the plasma membrane?

along microtubules

_____ junctions link cytoskeletal filaments of adjacent animal cells in one place, like a rivet.

anchoring

In bacterial cells, what is the function of flagella?

cell movement

The rigid _____ of most bacterial cells surrounds the cell membrane, protecting the cell and giving the cell shape.

cell wall

What surrounds the cell membrane of most bacteria and provides structure and protection?

cell wall

gap junctions

channels for the exchange of substances between adjacent animal cells

An organelle found in plant cells and some members of the kingdom Protista but not in animal cells is a

chloroplast

What plant organelle is shown in the image and contains photosynthetic pigments?

chloroplast

Short, numerous, hairlike structures that surround some cells like a fringe, are powered by microtubules, and have coordinated movements are called

cillia

anchoring junctions

connect animal cells to the extracellular matrix or to adjacent animal cells in one place

central vacuole in plants

contains enzymes, salts, pigments, sugars, and acids

The ______ includes all of the cell contents between the nucleus and the cell membrane.

cytoplasm

food vacuole in amoebas

digest nutrients engulfed by cell

a prokayotic cell

does not have a nucleus

Nuclear pores have proteins that open and close, controlling flow of cell solutions and molecules in and out of the nuclear envelope (a double-thick membrane). In this, nuclear pores are similar in structure and function to

gap junctions

A eukaryotic cell

has membrane-bounded organelles.

In eukaryotic cells, the nucleus is an organelle that functions in

housing the cell's DNA

The head of a phospholipid is ______, meaning its polar covalent bonds attract water, but the tails of a phospholipid are _____ and this water-insoluble.

hydrophillic; hydrophobic

What is the function of recognition proteins in the plasma membrane?

identify the cell as belonging to the body and certain tissue type

The ____ microscope is ideal for viewing living cells that are between 200 nanometers and 1 millimeter in size.

light

What type of microscope passes light through a transparent or thinly sliced specimen to generate true-color views of cells?

light microscope

Organelles carry out specialized functions in the cell and are enclosed by

membranes

A wild duck needs a steady supply of energy to be able to fly for hours. Domesticated chickens rarely fly. As a result, you would expect to find _____ in the breast muscles of wild ducks than in domesticated chickens.

more mitochondria

In prokaryotic cells, DNA congregates in an area called the

nucleoid

The area within the cytoplasm of a prokaryotic cell where the circular DNA molecule is found is called the ______ and is not bounded by a membrane.

nucleoid

the most prominent organelle visible in most eukaryotic cells is the

nucleus

The main organelles and structures involved by distinct function with milk production and secretion in their correct sequence are

nucleus, nuclear pore, rough ER, smooth ER, transport vesicle, Golgi apparatus, and vesicle for secretion

Within the cytoplasm of eukaryotic cells, there are multiple specialized compartments called

organelles

primary cell wall

outer, more flexible layer of the cell wall

All cells are surrounded by cell membranes, also called plasma membranes, that separate the cytoplasm from the

outside environment

Biological membranes are selectively ____, meaning they allow only specific types of molecules to pass into or out of the cell.

permeable

In cell membranes, what part of a phospholipid molecule is oriented toward the outside of the bilayer?

phosphate head

The cell membrane is composed of a type of lipid molecule called a(n) ______, which has two fatty acids and a phosphate group extending from a glycerol molecule

phospholipid

What molecules are key components of cell membranes and are arranged in bilayers to form membranes?

phospholipids

Tunnels called ______ occur in the cell walls of two adjacent plant cells and allow the cells to communicate and exchange materials with each other.

plasmodesmata

Water, nutrients, hormones, and some organelles flow between adjacent plant cells through special channels in the cell wall called

plasmodesmata

a central vacuole of a mature plant cell

produces turgor pressure

In all cells, RNA and ribosomes play a role in the production of ______, which are molecules that carry out all of the cell's work.

proteins

What component of cell membranes functions in a diversity of roles, including recognition, transport, adhesion, and facilitating reactions?

proteins

contractile vacuole (paramecium)

pumps excess water out of the cell

middle lamella

region where adjacent cell walls meet

A structure found in cells of all three domains, prokaryotes and eukaryotes, is the

ribosome

secondary cell wall

rigid, innermost portion of the cell wall

Lipids called ______, which include cholesterol, are membrane components that aid in membrane fluidity.

steriods

Why are ions and polar molecules unable to pass directly through a cell membrane?

the interior of the phospholipid bilayer is hyrdophobic.

_____ proteins are embedded in the cell membrane and act as passageways for water-soluble materials into or out of the cell.

transport

What type of cell membrane protein allows molecules and ions to enter or exit the cell?

transport proteins

An understanding of cellular biology is helping us find new treatments for many diseases.

true

Endosymbiosis theory is proposed in large part because of the resemblance of mitochondria and chloroplast structures to prokaryotes.

true

Plasmodestmata

tunnels for the exchange of substances between adjacent plant cells

How do sperm move to fertilize eggs?

with flagella made of microtubules

Select all of the following that are components of phospholipid molecules, which are the main constituents of cell membranes.

- two fatty acids - phosphate group - glycerol molecule

In bacterial cells, the nucleoid is where the cell's ____ congregates.

DNA

Most cells have a small size that is less than 0.1 mm in diameter to maximize surface area relative to volume.

True

Single-celled organisms are the most abundant organisms on the planet.

True

Select all the roles that membranes play in cells

- transport substances into and out of the cell. - receive and respond to external stimuli - enclose organelles in eukaryotic cells

tight juntions

fuse cell membranes of adjacent animal cells, forming a barrier

select all of the following that are found in chloroplasts.

- DNA - stroma - ribosomes - photosynthetic pigments - thylakoids

Select all of the following that are able to pass freely through the phospholipid bilayer.

- O2 and CO2 - lipids - small nonpolar molecules

Select all of the following that are examples in which the ratio of surface area to volume of cells is increased.

- amoebas have extensions that are examples in which the ratio of surface area to volume of cells is increased. - paramecia are horizontally flattened in shape. - nerve cells are long and thin.

Select all of the following that are true about lysosomes.

- can fuse with vesicle carrying debris from outside the cell or damaged organelles. - contain enzymes tagged with sugars - enzymes inside the lyosome perform hydrolysis reactions

Select all of the following that differ between domains Bacteria and Archaea.

- chemical composition of flagella - evolutionary relationships to eukaryotes - molecules that compose the cell membranes

Select all of the following that describe tight junctions.

- create the "blood-brain barrier" - membrane proteins connect to actin in the cytoskeletons of adjacent cells - join adjacent cells into sheets

Select all of the following that are true about organisms in Domain Bacteria.

- earth's oldest organisms - some are used to make pharmaceuticals - some live in human intestines and help with digestion - important decomposers and producers

Select all of the cell parts that are involved in the endomembrane system.

- endoplasmic reticulum - Golgi apparatus - lysosomes - vacuoles - nuclear envelops

Select all of the following that are present in bacterial cells.

- enzymes, cytoplasm, ribosomes, DNA

Select all of the functions of the bacterial cell wall.

- give the cell its shape - prevent the cell from bursting - protect the cell

Cells need increased surface area for diffusion of nutrients and wastes. Cells increase their surface area by

- having microscopic extensions of the cell membrane - having a flattened shape - being long and thin - having specialized organelles to move components throughout the cell

Select all of the characteristics of eukaryotic cells.

- larger than prokaryotic cells - system of internal membranes - nucleus

Select ways that cells avoid surface area limitations.

- long or thin shape - efficient transportation system within cell

Select all of the following types of cells that usually possess cell walls.

- plant - archaea - bacteria - fungi - algae

Select all of the following that are able to move laterally within the cell membrane, giving it the description of a fluid mosaic.

- proteins - phospholipids

Select all of the following that are components of cell membranes.

- proteins - phospolipids - steroids

Select all of the following that are true about prokaryotes?

- simplest types of life - lack a nucleus - most ancient forms of life on Earth

Some members of the Archaea domain are often referred to as extremophiles because many live in conditions of extreme

- temperature - salinity - heat - acidity

Key genetic sequences suggest that archaea are more closely related to members of domain ______ than they are to members of Domain Bacteria.

Eukarya

_____ cells are the simplest forms of life and lack a nucleus.

Prokaryotic

Flagella move by way of dynein proteins that connect microtubules and force them to shift back and forth to bend or rotate the flagella.

True

What type of microscope allows resolution of objects that are about 5 nanometers in size?

electron

plasma membrane

encloses the cytoplasm and lies just under the secondary cell wall

Peroxisomes are organelles that originate at the ______ and contain enzymes that dispose of toxic substances.

endoplasmic reticulum

Proteins that increase the speed of chemical reactions on the cell membrane and in other parts of the cell are called ______.

enzymes

What is the function of membrane proteins that are enzymes?

facilitate chemical reactions

All living cells have a cell wall

false

Because mitochondria, chloroplasts, and other plastids have their own DNA and ribosomes within double membranes, they are also considered cells.

false

Most living cells are small in size because they need a small ratio of surface area to volume.

false

In some types of bacteria, appendages called ______ rotate like a propeller and allow movement forward or backward.

flagella