BioH S1 ALL UNITS

phosopholipid bilayer

composition of plasma membrane, two layers of phosopholipids arranged tail-to-tail

Cholesterol

A lipid that forms an essential component of animal cell membranes and acts as a precursor molecule for the synthesis of other biologically important steroids. Acts as a buffer to maintain membrane fluidity

integral protein

A transmembrane protein with hydrophobic regions that extend into and often completely span the hydrophobic interior of the membrane and with hydrophilic regions in contact with the aqueous solution on one or both sides of the membrane (or lining the channel in the case of a channel protein).

peripheral protein

A protein loosely bound to the surface of a membrane or to part of an integral protein and not embedded in the lipid bilayer.

Semi-permeable

characteristic of a cell membrane which allows some molecules to pass through but not others

Diffusion

Movement of molecules from an area of higher concentration to an area of lower concentration.

osmosis

Diffusion of water through a selectively permeable membrane

Hydrophilic

Attracted to water

Hydrophobic

Having an aversion to water; tending to coalesce and form droplets in water.

polar

Molecule with partial charges. Mixes with water.

nonpolar

No partial charges. Do not mix with water. A molecule in which all atoms have the same electronegativity and the electron distribution is equal

concentration gradient

difference in the concentration of a substance from one location to another

equilibrium

Equilibrium is reached when net movement stops

(1) Concentration is = on both sides of semipermeable membrane

net flow

the direction in which most particles are moving during diffusion or osmosis

Hypotonic

Having a lower concentration of solute than another solution

Hypertonic

when comparing two solutions, the solution with the greater concentration of solutes

DNA

A complex molecule containing the genetic information that makes up the chromosomes.

turgid cell

a plant cell that has absorbed water (due to osmosis) and has cytoplasm that is pressing outwards on the cell wall

nuclear envelope

layer of two membranes that surrounds the nucleus of a cell

surface area to volume ratio

A ratio that decreases as cells grow, so that it sets a limit to the size of cells.

cell cycle

series of events in which a cell grows, prepares for division, and divides to form two daughter cells

G0 phase

A nondividing state occupied by cells that have left the cell cycle, sometimes reversibly.

G1 phase

* The first gap, or growth phase, of the cell cycle, consisting of the portion of interphase before DNA synthesis begins.

G2 phase

stage of interphase in which cell duplicates its cytosol and organelles

S phase

The synthesis phase of the cell cycle; the portion of interphase during which DNA is replicated.

cell plate

In a plant cell, midline of dividing cells. Becomes the cell wall eventually.

cleavage furrow

The first sign of cleavage in an animal cell; a shallow groove in the cell surface near the old metaphase plate.

Equator of the cell

the central plane of the spindle in a dividing cell, to which chromosomes migrate during the metaphase of mitosis or meiosis.

mitosis

cell division in which the nucleus divides into nuclei containing the same number of chromosomes

prophase

1st (and longest) phase of mitosis, during which

* the nuclear envelope around the chromosomes disappears


* the centrioles separate and place the spindle fibers on opposite sides of the nucleus

metaphase

2nd phase of mitosis, during which **the chromosomes line up across the center of the cell**

anaphase

3rd phase of mitosis in which **the chromosomes separate and move to opposite ends of the cell**

telophase

the final phase of mitosis, in which the chromatids (or chromosomes) reach opposite ends of the cell and **two nuclei are formed.**

cytokinesis

division of the cytoplasm to form two separate daughter cells

glycolipids

phospholipids with sugars attached (covalently bonded to lipids)

* both receptor AND recognition proteins
* increase membrane stability by forming H bonds with water molecules

centromere

the region of the chromosome that holds the two sister chromatids together during mitosis

chromosome

* a gene-carrying structure found in the nucleus


* each chromosome consists of one very long DNA molecule and associated proteins.

sister chromatids

* **replicated forms of a chromosome** joined together by the centromere
* eventually separated during mitosis

nucleus

* a part of the cell containing DNA and RNA


* responsible for growth and reproduction

spindle fiber

emerge from centrioles, attach to chromosomes to pull them apart **during mitosis**

receptor protein

a protein that binds specific signal molecules, causing the cell to respond

recognition protein

plasma membrane protein that identifies a cell as belonging to **self** (one's own body or species)

adhesion protein

membrane protein that helps cells stick together **in animal tissues**

glycoprotein

* protein with 1+ carbohydrates covalently attached to it
* recognition protein
* cell adhesion (helps cells attach to other cells)

transport protein

a protein that helps a certain substance to **cross the membrane**

centrioles

structures occurring in pairs and involved in the development of spindle fibers in cell division.

endocytosis

process by which a cell takes material into the cell by infolding of the cell membrane

exocytosis

a process by which the contents of a vesicle are released to the exterior membrane of the cell membrane.

facilitated diffusion

* process of diffusion in which molecules pass across the membrane through cell membrane channels


* does NOT require energy

active transport

* movement of substances across a cell membrane against a concentration gradient


* requires an input of energy

pump protein

A molecule that actively transports molecules in and out of cells using energy

Enzyme

A type of protein that speeds up a chemical reaction in a living thing

what is the main difference between cytokinesis in animal & plant cells?

in plant cells, a cell wall is formed between the 2 daughter cells in animal cells, cleavage furrow is formed between the 2 daughter cells

what happens in interphase

(gap) G1: the cell prepares for DNA replication Synthesis: DNA replication G2: the cell makes proteins while waiting for cell division Mitosis: nuclear division

prophase

nuclear envelope disappears spindle fibers attach to the chromosomes

metaphase

spindle fibers align the chromosomes in the middle

anaphase

sister chromatids separate and move to the opposite sides of the pole

telophase

nuclear envelopes form around each (to-be) cell

cytokinesis

cell division

photon

a particle of light

Pigment

a compound that absorbs light energy & harvests it for photosynthesis found in photosystems

Chlorophyll

green pigment in plants that absorbs light energy used to carry out photosynthesis

electron

A subatomic particle that has a negative charge

accessory pigment

compound other than chlorophyll that absorbs light at different wavelengths than chlorophyll

photosystem

a cluster of pigments embedded into a thylakoid membrane proteins that carry out the absorptions of light & the transfer of electrons

primary electron acceptor

an acceptor of electrons lost from chlorophyll a found in the thylakoid membrane

photolysis

during the LDR, 2 water molecules are broken down into O, H+, and electrons

oxidation

the loss of electrons from a substance involved in a redox reaction.

reduction

gain of electrons

electron transport chain

A sequence of electron carrier molecules (membrane proteins) that shuttle electrons during the redox reactions that release energy used to pump H+ ions and generate a concentration gradient.

H+ pump

A transporter that actively moves H+ across a cell membrane , thereby generating a gradient that can be used by the cell, for example, to import other solutes.

H+ gradient

movement of H+ ions through ATP Synthase powers the phosphorylation of ADP

ATP synthase

large protein in the cell membrane that uses energy from H+ ions to phosphorylate ADP to make ATP

NADPH

an electron carrier involved in photosynthesis light drives electrons from chlorophyll to NADP+, forming NADPH provides the high-energy electrons for the reduction of CO2 to sugar in the Calvin cycle.

Chloroplast

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

Thylakoid

a membrane system found within chloroplasts that contains the components for photosynthesis

grana

stacks of thylakoids

Thylakoid membrane

photosynthetic membrane within a chloroplast that contains light gathering pigment molecules and ETCs.

thylakoid space

space inside thylakoid.

stroma

fluid portion of the chloroplast outside the thylakoids

light-dependent reactions

set of reactions in photosynthesis that use energy from light to produce ATP and NADPH

Calvin Cycle

reactions of photosynthesis in which energy from ATP and NADPH is used to build high-energy compounds such as sugars

ADP

(Adenosine Diphosphate) The compound that remains when a phosphate group is removed from ATP, releasing energy

ATP

(adenosine triphosphate) main energy source that cells use for most of their work

Phosphorylation

transfer of a phosphate group , usually from ATP, to a molecule. nearly all cellular work depends on ATP energizing other molecules by phosphorylation.

oxidative phosphorylation

production of ATP using energy derived from the redox reactions of an ETC the third major stage of cellular respiration.

substrate-level phosphorylation

The enzyme-catalyzed formation of ATP by direct transfer of a phosphate group to ADP from an intermediate substrate in catabolism.

Carbon Fixation

The initial incorporation of carbon from CO2 into an organic compound by an autotrophic organism

rubisco

The most abundant protein on earth. Performs Carbon Fixation in the Calvin Cycle.

RuBP

ribulose biphosphate; a five-carbon carbohydrate that combines with CO2 to form two molecules of PGA in the first step of the Calvin Cylce

G3P

molecule that is made in the Calvin cycle; glucose is formed when two of these molecules combine

3PGA

first organic compound produced in the Calvin cycle. It is later reduced into G3P

Glucose

A simple sugar that is an important source of energy.

Reduction (Calvin Cycle)

PGA is converted to G3P with high energy electrons from NADPH and energy from ATP

Regeneration (Calvin Cycle)

The remaining G3P is used in reactions that use ATP to regenerate RuBP

Photosynthesis

process by which plants and some other organisms use light energy to convert water and carbon dioxide into oxygen and high-energy carbohydrates such as sugars and starches

respiration

The process by which cells break down simple food molecules to release the energy they contain.

anaerobic respiration

Respiration that does not require oxygen

Fermentation

A catabolic process that makes a limited amount of ATP from glucose without an electron transport chain and that produces a characteristic end product, such as ethyl alcohol or lactic acid.