HUMANBIOLOGY_CHAPTERTHREE

cell

smallest unit of life that can function independently

cell theory

the ideas that all living matter consists of cells, cells are the structural and functional units of life, and all cells come from preexisting cells

ribosome

a structure built of RNA and protein where mRNA anchors during protein synthesis

cell membrane

the boundary of a cell, consisting of proteins embedded in a phospholipid bilayer; also called the plasma membrane

cytoplasm

the watery mixture that occupies much of a cell’s volume; in eukaryotic cells, it consists of all materials, including organelles, between the nuclear envelope and the cell membrane

cytosol

the fluid portion of the cytoplasm

prokaryote

a cell that lacks a nucleus and other membrane-bounded organelles; bacteria and archaea

vesicle

a membrane-bounded sac that transports materials within a cell

nucleus (cell)

the membrane-bounded sac that contains DNA in a eukaryotic cell

nucleolus

a structure within the nucleus where components of ribosomes are assembled

lysosome

organelle in a eukaryotic cell that buds from the Golgi apparatus and enzymatically dismantles molecules, bacteria, and worn-out cell parts

mitochondrion (pl. mitochondria)

organelle that houses the reactions of cellular respiration in eukaryotes

chloroplast

organelle housing the reactions of photosynthesis in eukaryotes

cytoskeleton

framework of protein rods and tubules in eukaryotic cells

compound microscopes

uses two or more lenses to focus visible light, requires that specimens be transparent to view internal features, and type of light microscope

Select all of the following that are present in all cells?

RNA, ribosomes, DNA, proteins, cell membrane, and cytoplasm

The simplest forms of life are ______ cells, which lack a nucleus.

prokaryotic

Whether bacterium or blue whale, every organism is made of

cells

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

some live in human intestines and help with digestion, some are used to make pharmaceuticals, and important decomposers and producers

The ____ theory states that all life is composed of one or more cells, which are the fundamental units of all life.

cell

Protists, plants, fungi, and animals are organisms in the domain

Eukarya

What is a correct description of a confocal microscope? 

A laser is focused through a lens to the object, and the emitted light passes through a pinhole.

Select all the roles that membranes play in cells.

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

All cells have a cell ______ that surrounds the cytoplasm and forms a boundary between the cell and its environment.

membrane

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

permeable

What is the most ancient type of life on Earth?

prokaryotes

Embedded in the cell membrane, ______ proteins act as passageways for water-soluble materials into or out of the cell.

transport

Bacteria are the most abundant and diverse organisms.

True

What are the structures indicated by the arrows in the picture that have pinched off the Golgi apparatus and will deliver their contents to another part of the cell?

vesicles

Domain Eukarya includes ______.

all organisms with eukaryotic cells

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

outside environment

Select all of the following that are able to pass freely through the phospholipid bilayer without the assistance of transport proteins.

lipids, O₂ and CO_2, and small nonpolar molecules

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

transport proteins

Select all of the following that describe organelles called vesicles.

part of the endomembrane system, transport materials inside cells, and pinch off from one organelle and fuse with another

What is the function of a ribosome?

to manufacture proteins

What organelle of the endomembrane system breaks down debris, food, and old cell parts with special dismantling enzymes?

lysosome

In eukaryotic cells, the DNA that codes for the cell's proteins is stored in a membrane-bounded organelle called the

nucleus

Cellular respiration extracts energy from food and takes place in the organelle called a _____.

mitochondrion

The organelle that is the site of photosynthesis in plant cells is the _____ , which is a type of plastid.

chloroplasts

The nucleolus is a dense spot in the nucleus where components of ______ are assembled.

ribosomes

Microfilaments, intermediate filaments, and microtubules comprise the ______, which is a network of proteins that provide a structural framework within the cell.

cytoskeleton

The cell structure that manufactures proteins is called a ______.

ribosome

Organelles called lysosomes contain ______ that break down food particles, old organelles, and other cellular debris.

enzymes

Select all of the following types of organisms that usually have cell walls.

archaea, algae, fungi, plants, and bacteria

What eukaryotic organelle functions in the production of cellular energy by cellular respiration?

mitochondrion

What plant organelle contains photosynthetic pigments?

chloroplast

What is the network of protein fibers and tubules inside the cell that provides support and aids in cell division and movement?

cytoskeleton

Select all of the functions of cell walls.

regulate cell volume, impart shape, and prevent the cell from bursting

What structure is found outside the cell membranes of plants, fungi, and many prokaryotes and provides shape and protection for cells? 

cell wall