Biology 1 Exam Study Guide

Question 1

Define:

Biosphere

Answer 1

h consists of all life on Earth and all the places
where life exists: most regions of land, most bodies of water, the atmosphere to an altitude of
several kilometers, and even sediments far below the ocean floor.

Question 2

Define:

Ecosystem

Answer 2

consists of all the living things in a particular area, along with all the nonliving components of the environment with which life interacts, such as soil, water, atmospheric gases, and light.

Question 3

Define:

Community

Answer 3

The array of organisms inhabiting a particular ecosystem.

Question 4

Define:

Populations

Answer 4

consists of all the individuals of a species living within the bounds of a specified area that interbreed with each other.

Question 5

Define:

Systems Biology

Answer 5

The exploration of a biological system by analyzing the interactions among its parts. In this context, a single leaf cell can be considered a system, as can a frog, an ant colony, or a desert
ecosystem.

Question 6

Define:

Tissue

Answer 6

A group of cells that work together, performing a specialized function.

Question 7

Define:

Molecule

Answer 7

Is a chemical structure consisting of two or more units called atoms, represented as balls in this computer graphic of a chlorophyll molecule.

Question 8

Define:

Genome

Answer 8

The entire “library” of genetic instructions that an organism
inherits

Question 9

Define:

The 3 Domains of Life

Answer 9

Bacteria, Archea, and Eukarya

Question 10

Define:

Protist

Answer 10

Are mostly unicellular eukaryotes and some relatively simple multicellular relatives

Question 11

Define:

Trace Elements

Answer 11

These are required by an organism in only minute quantities. Some trace elements, such as iron (Fe), are needed by all forms of life; others are required only by certain species. For example, in vertebrates (animals with backbones), the element iodine (I) is an essential ingredient of a hormone produced by the thyroid gland.

Question 12

Define:

Radioactive Isotope

Answer 12

A type of isotope in which the nucleus decays spontaneously, giving off particles and energy. When the radioactive decay leads to a change in the number of protons, it transforms the atom to an atom of a different element. For example, when a carbon-14 (14C) atom decays, a neutron decays into a proton, transforming the atom into a nitrogen (14N) atom.

Question 13

Define:

Electron Shells

Question 14

Define:

Orbital

Answer 14

The three-dimensional space where
an electron is found 90% of the time.

Question 15

Define:

Covalent Bond

Answer 15

Is the sharing of a pair of valence electrons
by two atoms. For example, let’s consider what happens when two hydrogen atoms approach each other. Recall that hydrogen has 1 valence electron in the first shell, but the shell’s capacity
is 2 electrons. When the two hydrogen atoms come close enough for their 1s orbitals to overlap, they can share their electrons

Question 16

Define:

Nonpolar Covalent Bond

Answer 16

In a covalent bond between two atoms of the same element, the electrons are shared equally because the two atoms have the same electronegativity—the tug-of-war is at a standoff.

Question 17

Define:

Polar Covalent Bond

Answer 17

When an atom is bonded to a more electronegative atom, the electrons of the bond are not shared equally.

Question 18

Define:

Electronegativity

Answer 18

Atoms in a molecule attract shared bonding electrons to varying degrees, depending on the element. What is the attraction of a particular atom for the electrons of a covalent bond?

Question 19

Define:

Ionic Bond

Answer 19

Because of their opposite charges, cations and anions attract
each other; this attraction is what type of bond?

Question 20

Define

Ionic Compounds

Answer 20

Compounds formed by ionic bonds. Also known as salts.

Question 21

Define:

Hydrogen Bond

Answer 21

When a hydrogen atom is covalently bonded to an electronegative atom, the hydrogen atom has a partial positive charge that allows it to be attracted to a different electronegative atom with
a partial negative charge nearby. Note: In living cells, the electronegative partners are usually oxygen or nitrogen atoms.

Question 22

Define:

Plasma Membrane

Answer 22

Functions as a selective barrier that allows passage of enough oxygen, nutrients, and
wastes to service the entire cell.

Question 23

Define:

Endoplasmic Reticulum (ER)

Answer 23

A network of membranous sacs and tubes; active in membrane synthesis and other synthetic
and metabolic processes; has rough
(ribosome-studded) and smooth regions.

Question 24

Define:

Nuclear Envelope

Answer 24

A double membrane enclosing the
nucleus; perforated by pores; continuous with ER.

Question 25

Define:

Nucleolus

Answer 25

A nonmembranous structure involved in production of ribosomes; a nucleus has
one or more nucleoli.

Question 26

Define

Ribosomes

Answer 26

Complexes that make proteins; free in
cytosol or bound to rough ER or nuclear
envelope. These complexes are also made of ribosomal RNAs and proteins. These structures are the cellular components that carry out protein synthesis.

Question 27

Define:

Lysosome

Answer 27

The digestive organelle where
macromolecules are hydrolyzed. many eukaryotic cells use to digest (hydrolyze) macromolecules. These enzymes work best in the acidic environment found in lysosomes. If a lysosome breaks open or leaks its contents, the released enzymes are not very active because the
cytosol has a near-neutral pH. However, excessive leakage from a large number of lysosomes can destroy a cell by self-digestion.

Question 28

Define:

Golgi Apparatus/Body

Answer 28

An organelle active in synthesis, modification, sorting, and secretion of cell products.

Question 29

Define:

Peroxisome

Answer 29

An organelle with various specialized metabolic
functions; produces hydrogen peroxide as a by-product and then converts it to water. They are roughly spherical and often have a granular or crystalline core that is thought to be a desne collection of enzyme molecules. Chloroplasts and mitochondria cooperate with this term in certain metabolic functions (TEM). It also contains enzymes that remove hydrogen atoms from various substrates and transfer them to oxygen (O2), producing hydrogen peroxide (H2O2) as a by-product (from which the organelle derives its name). These reactions have many different functions. Some types of this term use oxygen to break fatty acids down into smaller molecules that are transported to mitochondria and used as fuel for cellular respiration. In the liver it detoxifies alcohol and other harmful compounds by transferring hydrogen from the poisonous
compounds to oxygen.

Question 30

Define:

Microvilli

Answer 30

Membrane projections that
increase the cell’s surface area.

Question 31

Define:

Cytoskeleton

Answer 31

A network of fibers extending throughout the cytoplasm that reinforces a cell’s shape; functions in cell movement; components are made of protein. Includes: microfilaments, Intermediate filaments, and microtubules.

Question 32

Define:

Centrosome

Answer 32

Region where the cell’s microtubules are
initiated; contains a pair of centrioles.

Question 33

Define:

Flagellum

Answer 33

Motility structure present in some animal cells,
composed of a cluster of microtubules within an
extension of the plasma membrane.

Question 34

Define:

Chromatin

Answer 34

Material consisting of DNA and proteins; visible in
a dividing cell as individual condensed chromosomes.

Question 35

Define:

Chloroplast

Answer 35

Found in Plant Cells: : Photosynthetic
organelle; converts energy of sunlight to chemical energy stored in sugar molecules.

Question 36

Define:

Cell Wall

Answer 36

Found in Plant Cells: Outer layer that maintains
cell’s shape and protects cell from
mechanical damage; made of cellulose,
other polysaccharides, and protein

Question 37

Define:

Central Vacuole

Answer 37

Found in Plant Cells: prominent organelle
in older plant cells; functions include storage,
breakdown of waste products, and hydrolysis
of macromolecules; enlargement of this structure is a major mechanism of plant growth.

Question 38

Define:

Plasmodesmata

Answer 38

The cytoplasmic channels through cell walls
that connect the cytoplasms of adjacent cells.

Question 39

Define:

Chromosomes

Answer 39

Structures that carry the genetic information. Each chromosome contains one long DNA
molecule associated with many proteins, including small basic proteins called histones. Some of the proteins help coil the DNA molecule of each chromosome, reducing its length and allowing it to fit into the nucleus. 23 pairs for a total of 46.

Question 40

Define:

Chromatin

Answer 40

The complex of DNA and proteins making up chromosomes.

Question 41

Define:

Nucleolus

Answer 41

A prominent structure within the nondividing nucleus is this structure which appears through the electron microscope as a mass of densely stained granules and fibers adjoining part of the chromatin. Here a type of RNA called ribosomal RNA (rRNA) is synthesized from genes in the DNA. Also in this structure, proteins imported from the cytoplasm are assembled with rRNA into large and small subunits of ribosomes. These subunits then exit the nucleus through the
nuclear pores to the cytoplasm, where a
large and a small subunit can assemble
into a ribosome. Sometimes there are
two or more nucleoli; the number
depends on the species and the stage in
the cell’s reproductive cycle.

Question 42

Define:

Nuclear Envelope

Answer 42

Part of the cell that encloses the nucleus, separating its contents from the cytoplasm. It is a double membrane. The two membranes, each a lipid bilayer with associated proteins, are separated by a space of 20–40 nm. The envelope is perforated by pore structures that are about 100 nm in diameter. At the lip of each pore, the inner and outer membranes of the nuclear envelope are continuous. An intricate protein
structure called a pore complex lines each pore and plays an important role in the cell by regulating the entry and exit of proteins and RNAs, as well as large complexes of macromolecules. Except at the pores, the nuclear side of the envelope is lined by the nuclear lamina.

Question 43

Define:

Nucelar Lamina

Answer 43

A netlike array of protein filaments (in animal cells, called intermediate filaments) that maintains the shape of the nucleus by mechanically supporting the nuclear envelope. There is also much evidence for a nuclear matrix, a framework of protein fibers extending throughout the nuclear interior. The nuclear
lamina and matrix may help organize the genetic material so it functions efficiently.

Question 44

Define:

Glycoproteins

Answer 44

Proteins with carbohydrates covalently bonded to them. The carbohydrates are attached to the proteins in the ER lumen by enzymes built into the ER membrane.

Question 45

Define:

Transport Vesicles

Answer 45

Vesicles in transit from one part of the cell to another.

Question 46

Define:

Phagocytosis

Answer 46

Lysosomes carry out intracellular digestion in a variety of circumstances. Amoebas and many other unicellular protists eat by engulfing smaller organisms or food particles,
a process called?

Question 47

Define:

Cristae

Answer 47

The infoldings of the inner membrane of a cell. This is what makes the inner membrane convoluted opposed to the outer membrane being smooth.

Question 48

Define:

Thylakoids

Answer 48

Flattened, membraneous interconnected sacs found in the chloroplast. In some regions, they are stacked like poker chips.

Question 49

Define:

Granum

Answer 49

The stacked structures of thylakoids.

Question 50

Define:

Stroma

Answer 50

The fluid found outside the thylakoids. It contains the chloroplast DNA and ribosomes as well as many enzymes.

Question 51

Define:

Plastids

Answer 51

The chloroplast is a specialized member of a family of closely related plant organelles called? More Info: One type of this term, the amyloplast, is a colorless organelle that stores starch (amylose), particularly in roots and tubers. Another is the chromoplast, which has pigments that give fruits and flowers their orange and yellow hues.

Question 52

Define:

Motor Proteins

Question 53

Define:

Proteoglycans

Answer 53

Consists of a small core protein with many carbohydrate chains covalently attached, so that it may be up to 95% carbohydrate. Large complexes of these can form when hundreds of “term” molecules become noncovalently attached to a single long polysaccharide molecule

Question 54

Define:

Plasmodesmata

Answer 54

Channels that connect cells.

Question 55

Define:

Desmosomes

Answer 55

Function like rivets, fastening cells together into strong sheets. Intermediate filaments made of sturdy keratin proteins anchor desmosomes in the cytoplasm. They attach muscle cells to each other in a muscle.

Question 56

Define:

Gap Junctions

Answer 56

Provide cytoplasmic channels from one
cell to an adjacent cell and in this way are similar in their function to the plasmodesmata in plants. These consist of membrane proteins extending from the membranes of the two cells. These proteins create pores through which ions, sugars, amino acids, and other small molecules may pass. They are necessary for communication between cells in many types of tissues, such as heart muscle, and in animal embryos.

Question 57

Define:

Adaptions

Answer 57

Inherited characteristics of organisms
that enhance their survival and reproduction in specific environments.

Question 58

Define:

Natural Selection

Answer 58

A process in which individuals that have certain inherited traits tend to survive and reproduce at
higher rates than do other individuals because of those traits.

Question 59

Define:

Homology

Answer 59

Similarity resulting in common ancestry.

Question 60

Define:

Homologous Structures

Answer 60

Represent variations on a structural theme that was present in their common ancestor. Adaptions of structures over time.