CELLS AND TISSUES

cells

are the structural units of all living things

50 to 100 trillion

The human body contains ______ of these tiny building blocks (cells)

principle of complementarity

According to the ______, the activities of cells are dictated by their structure (anatomy), which determines function (physiology)

collective activities of its cells

The activity of an organism depends on the ________

cells

are made up primarily of the same four elements—carbon, oxygen, hydrogen, and nitrogen—plus much smaller amounts of several other elements.

generalized cell

Although no one cell type is exactly like all others, cells do have the same basic parts, and there are certain functions common to all cells

3

How many regions does a cell have?

nucleus, plasma membrane, and the cytoplasm

what are the 3 main regions of the cell?

located near the center of the cell.

where is the nucleus located?

nucleus

It is surrounded by the semifluid cytoplasm, which in turn is enclosed by the plasma membrane, which forms the outer cell boundary.

cytoplasm

nucleus is surrounded by the semifluid ______

plasma membrane

forms the outer cell boundary

nucleus

For cells, “headquarters,” or the control center, is the ______

kernel

nucle = ______

deoxyribonucleic acid (DNA)

The genetic material, or ______, is a blueprint that contains all the instructions needed for building the whole body

genes

DNA has _____, which carry the instructions for building proteins

true

DNA is also absolutely necessary for cell reproduction

self-destruct

A cell that has lost or ejected its nucleus (for whatever reason) is destined to ______

oval or spherical

the nucleus is most often _____, its shape usually conforms to the shape of the cell.

The nucleus has three recognizable regions or structures: _____

nuclear envelope, nucleolus, and chromatin.

nuclear envelope

The nuclear boundary is a double membrane barrier called the _____

nuclear membrane

nuclear envelope is also called as _____

moat

nuclear membrane is a fluid-filled _____ or space

nuclear pores

the two layers of the nuclear envelope fuse, generating openings called_____

nuclear envelope

its function is that it allows some but not all substances to pass through it, but substances pass through it much more freely than elsewhere because of its relatively large pores.

nucleoplasm

The nuclear membrane encloses a jellylike fluid called ______

it is where other nuclear elements are suspended

what does nucleoplasm do?

nucleoli

The nucleus contains one or more small, darkstaining, essentially round bodies called _____

little nuclei

nucleoli also means _____

nucleolus

what do you call a singular nuclei?

nucleoli

are sites where cell structures called ribosomes are assembled

histones

When a cell is not dividing, its DNA is carefully wound around proteins called _____

chromatin

When a cell is not dividing, its DNA is carefully wound around proteins called histones to form a loose network of “beads on a string” called _____

chromatin

is scattered throughout the nucleus.

two daughter cells

When a cell is dividing to form _____,

chromosomes

When a cell is dividing to form two daughter cells, the chromatin threads coil and condense to form dense, rodlike bodies called ______

chroma

means ‘colored’

soma

means ‘body’

chromatin

when the cell is not dividing, it forms _____

chromosomes

when the cell is dividing, it forms _____

plasma membrane

is a fragile, transparent barrier that contains the cell contents and separates them from the surrounding environment.

plasma membrane

is important in defining the limits of the cell, it is much more than a passive envelope, or “baggie.”

two phospholipid (fat) layers

The structure of the plasma membrane consists of _____

tail to tail

The structure of the plasma membrane consists of two phospholipid (fat) layers arranged “______,”

proteins

what floats among the two phospholipid fat layers of the plasma membrane?

cholesterol

aside from protein, what else is scattered among the two phopholipid layers of the plasma membrane?

glycolipids

Some phospholipids may also have sugar groups attached, forming _____

hydrophilic

The polar “heads” of the lollipop-shaped phospholipid molecules are _____

polar “heads”

it is the main component of both the intracellular and extracellular fluids, and so they lie on both the inner and outer surfaces of the membrane.

hydrophobic

Their nonpolar fatty acid “tails,” being ______

nonpolar fatty acid “tails,”

they line up in the center (interior) of the membrane.

self-orienting property

what property of the phospholipids allows biological membranes to reseal themselves quickly when torn?

hydrophobic

The _____ makeup of the membrane interior makes the plasma membrane relatively impermeable to most water-soluble molecules.

cholesterol

what helps to both stabilize the plasma membrane and keep it flexible.

proteins

The _____ scattered in the lipid bilayer are responsible for most of the specialized functions of the membrane.

protein channels

some protein cluster together to form ______ (tiny pores) through which water and small water-soluble molecules or ions can move

carriers

other proteins act as ______ that bind to a substance and move it through the membrane.

glycoproteins

Branching sugar groups are attached to most of the proteins abutting the extracellular space. Such “sugar-proteins” are called ______

glycocalyx

cell surface is a fuzzy, sticky, sugar-rich area called ______

glycoproteins

determine your blood type, act as receptors that certain bacteria, viruses, or toxins can bind to, and play a role in cell-to-cell recognition and interactions.

cancer

Definite changes in glycoproteins occur in cells that are being transformed into _____ cells.

1. Glycoproteins in the glycocalyx act as an adhesive or cellular glue.

2. Wavy contours of the membranes of adjacent cells fit together in a tongue-and-groove fashion.

3. Special cell membrane junctions are formed. These junctions vary structurally depending on their roles.

Typically, cells are bound together in three ways:

tight junctions, desmosomes, and gap junctions

what are the main types of cell membrane junctions?

Tight junctions

are impermeable junctions that encircle the cells and bind them together into leakproof sheets.

Tight junctions

which junction does adjacent plasma membranes fuse together tightly like a zipper and prevent substances from passing through the extracellular space between cells?

tight junction

these junctions prevent digestive enzymes from seeping into the bloodstream.

tight junction

which junction is like a ‘zipper’?

Desmosomes

are anchoring junctions scattered like rivets along the sides of adjacent cells.

Desmosomes

They prevent cells subjected to mechanical stress (such as heart muscle cells and skin cells) from being pulled apart.

Desmosomes

these junctions are buttonlike thickenings of adjacent plasma membranes (plaques) that are connected by fine protein filaments.

Desmosomes

which junction prevents cell from tearing apart when stretched?

Gap junctions

also called as communicating junctions, function mainly to allow communication.

Gap junctions

These junctions are commonly found in the heart and between embryonic cells

connexons

In gap junctions, the neighboring cells are connected by hollow cylinders composed of proteins called _____ that span the entire width of the abutting membranes called transmembrane proteins.

transmembrane proteins

In gap junctions, the neighboring cells are connected by hollow cylinders composed of proteins called connexons that span the entire width of the abutting (neighbouring) membranes called ______

cytoplasm

is the cellular material outside the nucleus and inside the plasma membrane.

cytoplasm

It is the site of most cellular activities

cytoplasm

the “factory floor” of the cell.

cytosol, inclusions, and organelles

what are the three major components of cytoplasm?

cytosol

is semitransparent fluid that suspends the other elements.

solutes

Dissolved in the cytosol, which is largely water, are nutrients and a variety of other _____

Inclusions

are chemical substances that may or may not be present, depending on the specific cell type

cytosol

Most inclusions are stored nutrients or cell products floating in the _____

inclusion

a cellular “pantry” where items are kept on hand until needed.

organelles

means ‘little organs’

organelles

are specialized cellular compartments that are the metabolic machinery of the cell.

true

Each type of organelle is specialized to carry out a specific function for the cell as a whole, much like the organs carry out specialized functions for the whole body.

compartmentalization

is crucial to the organelle’s ability to perform their specialized functions for the cell.

mitochondrion

what is the singular form of mitochondria?

mitochondria

tiny, lozenge-like or sausage-shaped organelles, but in living cells they lengthen and change shape almost continuously.

mitochondrial wall

consists of a double membrane, equal to two plasma membranes placed side by side

cristae

The mitochondrial wall’s outer membrane is smooth and featureless, but the inner membrane has shelflike protrusions called _____

break down foods

Enzymes dissolved in the fluid within the mitochondria, as well as enzymes that form part of the cristae membranes, carry out the reactions in which oxygen is used to _____.

ATP molecules

As the foods are broken down, energy is released. Much of this energy escapes as heat, but some is captured and used to form _____.

ATP

It provides the energy for all cellular work, and every living cell requires a constant supply of _____ for its many activities.

Because the mitochondria supply most of ATP that is used as the energy for all cellular work

why is the mitochondria called as the ‘powerhouse of the cell’?

they huge amounts of ATP and have hundreds of mitochondria, which replicate themselves by pinching in half.

how does “busy” cells, such as liver and muscle cells use mitochondria and ATP?

Ribosomes

are tiny, bilobed, dark bodies made of proteins and one variety of RNA called ribosomal RNA

ribosomal RNA

Ribosomes are tiny, bilobed, dark bodies made of proteins and one variety of RNA called _____