Chapter 4 College Biology

differential interference light microscopes amplify

differences in density so that structures in living cells appear almost three dimensional

Which of the following would distinguish a bacterial cell from an animal cell?

presence of a cell wall

intermembrane space

the fluid filled space between the inner and outer mitochondrial membranes

cellular metabolism

the many chemical activities of the cells, occurs within organelles

mitochondrial matrix

the mitochondrial DNA, ribosomes, and many enzymes that catalyze some of the reactions of cellular respiration

hydrophilic heads

water loving, face outward exposed to water

Which of the following clues would tell you whether a cell is prokaryotic or eukaryotic?

whether or not the cell is partitioned into compartments

Thylakoid

A flattened membrane sac inside the chloroplast, used to convert light energy into chemical energy.

Cytoplasm

A jellylike fluid inside the cell in which the organelles are suspended

Cytoskeleton

A network of fibers that holds the cell together, helps the cell to keep its shape, and aids in movement

endomembrane system

A network of membranes inside and around a eukaryotic cell, related either through direct physical contact or by the transfer of membranous vesicles.

Centrosome

A structure in animal cells containing centrioles from which the spindle fibers develop.

Cyanide inhibits mitochondrial function; as a result, the rate of

ATP synthesis decreases

Magnification

An increase in the apparent size of an object

Lysosomes

An organelle containing digestive enzymes, made by the rough ER and processed in the Golgi apparatus

who discovered the microscope?

Antoine van Leeuwenhoek

the nucleus

Contains DNA and controls all cell activity by directing protein synthesis by making messenger RNA

Mitochondria and chloroplasts contain

DNA and ribosomes

Rough ER

ER that is dotted with ribosomes

Which of the following is part of the endomembrane system?

Golgi apperatus

Microfilaments

Long, thin fibers that function in the movement and support of the cell

In addition to phospholipids, the plasma membrane also contains proteins, many of which cross the width of the membrane. Which of the following statements best describes membrane-spanning proteins?

Membrane-spanning proteins contain both hydrophobic and hydrophilic amino acids and float freely in the membrane.

Mitochondria

Powerhouse of the cell, organelle that is the site of ATP (energy) production, carries out cellular respiration

who discovered cells?

Robert Hooke in 1665

Which of the following is a function of the central vacuole?

Storing compounds produced by the cell

smooth ER

That portion of the endoplasmic reticulum that DOES NOT have ribosomes.

What is the relationship between the Golgi apparatus and the plasma membrane?

The finished products of the Golgi apparatus may leave the cell through vesicles that fuse with the plasma membrane.

Microscopes have limitations

The human eye and the microscope have limits of resolution—the ability to distinguish between small structures. Therefore, the light microscope cannot provide the details of a small cell's structure.

Your intestine is lined with individual cells. No fluids leak between these cells from the gut into your body. Why?

The intestinal cells are bound together by tight junctions.

What do the rough endoplasmic reticulum, Golgi apparatus, and lysosomes have in common?

They are all membranous organelles comprising the endomembrane system.

Hydrophobic tails

Water fearing, face inward shielded from water

Resolution

a measure of the clarity of an image

Eukaryote cells are distinguished by having

a membrane enclosed nucleus and many membrane enclosed organelles that perform specific functions

a eukaryotic cell contains

a membrane-enclosed nucleus and various other organelles ("little organs"), which perform specific functions in the cell.

Which structure is exclusively associated with prokaryotic cells?

a nucleoid

prokaryote and eukaryote cells both have

a plasma membrane, cytosol (jellylike fluid), chromosomes that cary genes made of DNA, and ribosomes that make proteins

the nucleolus is

a prominent structure in the nucleus and the site of ribosomal RNA synthesis so ribosomes get made here

the rough ER makes

additional membrane for itself and secretory proteins

The membranous compartmentalization of a cell

allows different chemical conditions to be maintained in different parts of the cell

A scientist wants to magnify a pollen grain 8,000 times and examine the ridges and pores on its surface. Which instrument would be best?

an electron scanning microscope

vacuoles

are larges vesicles that have a variety of functions

Peroxisomes

are metabolic compartments that do not originate from the endomembrane system, unknown how they are related to other organelles. But they do break down fatty acids to be used as a cellular fuel

bound ribosomes

attached to the outside of the endoplasmic reticulum or nuclear envelope, makes proteins packed in certain organelles or exported

what is present in a plant cell but not an animal cell

cell wall containing cellulose, plasmodesmata, chloroplasts where photosynthesis occurs, and a central vacuole that stores water

_____ are found only in plant cells, but _____ are found in both plant and animal cells.

central vacuoles, ribosomes

The complex of proteins and DNA in a nondividing cell is called

chromatin

when a cell is not dividing, this complex of proteins and DNA appears as a diffuse mass within the nucleus

chromatin

DNA is associated with many proteins and is organized into

chromosomes

During cell reproduction, chromatin fibers coil up into structures called

chromosomes

The nucleoid region of a prokaryotic cell

contains the cell's DNA

The structural framework in a cell is the

cytoskeleton

what is involved in structural support, movement, and communication

cytoskeleton, plasma membrane, and cell wall

most animal cells are

embedded in an extracellular matrix.

membrane proteins are

embedded in the lipid bilayer

what is involved in the manufacture, distribution, and breakdown of molecules

endoplasmic reticulum, Golgi apparatus, lysosomes, vacuoles, and peroxisomes

the largest component of the endomembrane system is the

endoplasmic reticulum, an extensive network of flattened sacs and tubules

short projections

fimbriae that help attach prokaryotes to each other or their substrate

longer projections

flagella, propel a prokaryotic cell through its liquid environment

Stroma

fluid portion of the chloroplast, which contains chloroplast DNA, ribosomes, many enzymes, and a network of interconnected sacs

Cristae

folds in the inner membrane of mitochondria

Phospholipids

form a two layer sheet called a phospholipid bilayer in which hydrophilic heads and hydrophobic tails are

the plasma membrane

forms a flexible boundary between the living cell and its surroundings; made of phospholipids

intermediate filaments

found in the cells of most animals, reinforce cell shape and anchor some organelles and are often more permanent fixtures in the cell

What does a lysosome do?

fuse with food vacuoles and digest food, destroy bacteria engulfed by WBC or fused with other vesicles and break down damages organelles

The structures and organelles of eukaryotic cells perform four basic functions

genetic control, breakdown of molecules, energy processing, and structural support and movement

in plants, vacuoles functions

have digestive functions, contain pigments, or contain poisons that protect the plant

some protists have contractile vacuoles which

help to eliminate water from the protist

cell theory

idea that all living things are composed of cells, cells are the basic units of structure and function in living things, and new cells are produced from existing cells

mitochondria have two internal compartments

intermembrane space and mitochondrial matrix

cells must be

large enough to house DNA, proteins, and structures needed to survive and reproduce but remain small enough to allow for a surface to volume ration that will allow adequate exchange within the environment

cells that make a lot of proteins have a

large number of ribosomes

light microscope

light passes through one or more lenses to produce an enlarged image of a specimen

Which of the following organelles is found only in animal cells and NOT in most plant cells?

lysosomes

Which organelle plays a role in intracellular digestion?

lysosomes

what is present in animals cells but not plant cells

lysosomes and centrosomes, sperm cells dont have flagella

What carries instructions for making proteins from the nucleus into the cytoplasm?

mRNA

The main function of the rough endoplasmic reticulum is the production of

membrane and proteins secreted by the cell.

what were some things founded by a light microscope?

microorganisms, animal and plant cells, and some structures within cells

electron microscope

microscope that forms an image by focusing beams of electrons onto a specimen

what is involved in energy processing

mitochondria and chloroplasts

endosymbiont theory

mitochondria and chloroplasts were formerly small prokaryotes that began living within larger cells

the endomembrane system includes the

nuclear envelope, endoplasmic reticulum, golgi apparatus, lysosomes, vacuoles and the plasma membrane.

in a prokaryotic cell, the DNA is coiled into a region called

nucleoid

what is involved in the genetic control of the cell

nucleus and ribosomes

Chloroplast

organelle found in cells of plants and some other organisms that captures the energy from sunlight and converts it into chemical energy, site of photosynthesis

To enter or leave any cell, substances must pass through

plasma membrane

In plants, __________ are the cell junctions that allow the free exchange of small molecules that assist in communication. In animal cells, similar cell junctions are known as __________.

plasmodesmata ... gap junctions

the golgi apparatus serves as a molecular warehouse and processing station for

products manufactured by the ER, they travel in transport vesicles from the ER to the golgi

bacteria and archaea are

prokaryotic cells and are smaller and simpler in structure

Outside the plasma membrane of most prokaryotes is a fairly rigid, chemically complex cell wall, which

protects the cell and helps maintain its shape

ribosomes are involved in the cell's

protein synthesis, builds proteins from instructions from the nucleus

ribosomes are synthesized from

rRNA produced in the nucleolus

two sides of the golgi

recieving side that packages, and the shipping side

the double membrane nuclear envelope has pores that

regulate the entry and exit of large molecules and connects with the cell's network of membranes called the endoplasmic reticulum

electron microscopes can

resolve biological structures as small as 2 nanometers and magnify up to 100,000 times

Microtubules

shape and support the cell and act as tracks along which organelles equipped with motor proteins move

some proteins form channels that .... and other proteins serve as...

shield ions and other hydrophilic molecules as they pass through the hydrophobic center of the membrane, using energy to actively transport molecules into or out of the cell

some prokaryotes have surface projections (2 types)

short projections and longer projections

Where are lipids made in the cell?

smooth endoplasmic reticulum (ER)

granum

stack of thylakoids

Smooth endoplasmic reticulum

stores calcium ions in muscle cells

scanning electron microscope

study the detailed architecture of cell surfaces

transmission electron microscope

study the details of internal cell structure

free ribosomes

suspended in the cytosol, involved with making proteins in the cytoplasm

Smooth ER is involved in a variety of metabolic processes, including

the production of enzymes important in the synthesis of lipids, oils, phospholipids, and steroids, the production of enzymes that help process drugs, alcohol, and other potentially harmfal substances, and the storage of calcium ions

The stroma is the

thick fluid enclosed by the inner chloroplast membrane

The function of the nucleolus is

to manufacture ribosomal RNA

as cell size increases,

volume increases faster than surface area