Bio Test #2

phospholipid

a type of lipid molecule that is the main component of the cell membrane, also acts as a barrier to protect the cell against various environmental insults and more importantly, enables multiple cellular processes to occur in subcellular compartments

amphipathic molecule

chemical compounds containing both polar and nonpolar (apolar) portions in their structure

cholesterol

a structural component of cell membranes and serves as a building block for synthesizing various steroid hormones, vitamin D, and bile acids

polar molecule

a molecule containing an uneven distribution of charge due to the presence of polar covalent bonds; a molecule in which one end of the molecule is slightly positive, while the other end is slightly negative

fluid mosaic model

describes the structure of the cell membrane as a dynamic, flexible structure made up of different components

transmembrane protein

a type of integral membrane protein that spans the entirety of the cell membrane; allows for transport and cell signaling

diffusion

helps in the movement of substances in and out of the cells. The molecules move from a region of higher concentration to a region of lower concentration until the concentration becomes equal throughout

passive transport

the diffusion of a substance across a biological membrane without any input of energy

active transport

a process that involves the movement of molecules from a region of lower concentration to a region of higher concentration against a gradient or an obstacle with the use of external energy

facilitated diffusion

the passive movement of molecules along the concentration gradient aided by specific transport proteins. It is a selective process, i.e., the membrane allows only selective molecules and ions to pass through it

concentration gradient

the difference in concentration of a substance from one point to another; tend to move from areas of high concentration to low concentration

osmosis

the diffusion of water across a selectively permeable membrane

solution

a homogeneous mixture that is made up of a solute dissolved within a solvent

solvent

substance (molecule) with the ability to dissolve other substances (solutes) to form a solution

solute

a substance that can be dissolved into a solution by a solvent

tonicity

the capability of a solution to modify the volume of cells by altering their water content

hypertonic

when the surrounding liquid has a higher concentration of solutes than the intracellular fluid; water flows out of cell

hypotonic

when the surrounding fluid has a lower solute concentration than the intracellular fluid; water flows into the cell

isotonic

any external solution that has the same solute concentration and water concentration as another solution

energy

the capacity to cause change, or to move matter in a direction it would not move if left alone

autotrophs

an organism that can produce its own food using light, water, carbon dioxide, or other chemicals

heterotrophs

an organism that eats other plants or animals for energy and nutrients

aerobic

containing or requiring molecular oxygen

metabolism

the sum of all the chemical reactions in an organisms

ATP

a molecule composed of adenosine and three phosphate groups; the main energy source for cells

calories

the amount of energy that raises the temperature of 1 g of water by 1°C; measure of amount of energy in nutrients

carbohydrates

a biological molecule consisting of a simple sugar (a monosaccharide), two monosaccharides joined into a double sugar (a disaccharide), or a chain of monosaccharides (a polysaccharide); sugars & starches

monosaccharides

the simplest forms of sugar and the most basic units (monomers) from which all carbohydrates are built

disaccharides

a sugar molecule consisting of two monosaccharides (simple sugars) linked by a dehydration reaction

polysaccharides

a carbohydrate polymer consisting of many monosaccharides (simple sugars) linked by covalent bonds

cellulose

a large polysaccharide composed of many glucose monomers linked into cable-like fibrils that provide structural support in plant cell walls; cannot be broken by any enzyme produced by animals

glycogen

the stored form of glucose that's made up of many connected glucose molecules; serves as a temporary energy-storage molecule in liver and muscle cells

starch

a storage polysaccharide found in the roots of plants and certain other cells; a polymer of glucose

herbivore

an organism that mostly feeds on plants or algae

carnivore

an organism that mostly eats meat, or the flesh of animals

omnivore

an organism that eats plants and animals

cellular respiration

Use of oxygen (aerobic) to generate chemical energy (ATP) from organic fuel molecules (sugar); provides the energy cells need to maintain the functions of life; a series of chemical reactions that break down glucose to produce ATP

energy carriers

the source of energy for use and storage at the cellular level (NADH and ATP molecules)

glycolysis

A six-carbon glucose molecule is split in half to form two molecules of pyruvic acid; the energy released from breakdown of glucose is used to produce NADH and ATP molecules

citric acid cycle

the metabolic cycle that is fueled by acetyl CoA formed after glycolysis in cellular respiration; chemical reactions in the cycle complete the metabolic breakdown of glucose molecules to carbon dioxide; the cycle occurs in the matrix of mitochondria and supplies most of the NADH molecules that carry energy to the electron transport chain

electron transport chain

a series of electron carrier molecules that shuttle electrons during a series of chemical reactions; these reactions release energy that is used to make ATP; located in the inner mitochondrial membrane

cristae

a collection of proteins bound to the inner mitochondrial membrane and organic molecules, which electrons pass through in a series of redox reactions, and release energy

matrix

part of the mitochondria where the citric acid cycle takes place

inner and outer mitochondrial membranes

the thin layer that forms the outer boundary of a living cell or of an internal cell compartment

glucose

the main type of sugar in the blood and is the major source of energy for the body's cells

NADH

carries electrons from glucose and other fuel molecules and deposits them at the top of an electron transport chain; generated during glycolysis and the citric acid cycle

fermentation

another anaerobic (non-oxygen-requiring) pathway for breaking down glucose; enable cells to produce ATP
without the use of oxygen

lactic acid

a chemical your body produces when your cells break down carbohydrates for energy

cell division

the reproduction of a cell

mitosis

a process of cell duplication, in which one cell divides into two genetically identical daughter cells

meiosis

in a sexually reproducing organism, the process of cell division that produces haploid gametes from diploid cells within the reproductive organs

asexual reproduction

the creation of genetically identical offspring by a single parent, without the participation of gametes (sperm and egg)

sexual reproduction

the creation of genetically distinct offspring by the fusion of two haploid sex cells (gametes: sperm and egg), forming a diploid zygote

haploid

containing a single set of chromosomes; referring to an n cell

diploid

the presence of two complete sets of chromosomes in an organism's cells, with each parent contributing a chromosome to each pair; referring to a 2n cell

interphase

90% of the cell cycle; ells perform normal functions; cells grow in size (G1/G2 phases) and duplicates its DNA (S phase)

prophase

the first phase of mitosis; Chromosome condensation; breakdown of nuclear envelope; formation of spindle (microtubules) by centrosome

metaphase

Spindle microtubules attach to chromosomes; Chromosomes align in center

anaphase

Spindle pulls apart sister chromatids

telophase

Chromosomes decondense; Spindle apparatus is dismantled; Nuclear envelopes reform around separated chromosomes

cytokinesis

Division of the cytoplasm; Formation of a cleavage furrow, indentation at equator of the cell; Daughter cells pinch off from each other

chromosomes

threadlike structures made of protein and a single molecule of DNA that serve to carry the genomic information from cell to cell

chromatin

chain of nucleosomes (DNA + proteins); condenses into chromosomes during cell division

nucleosomes

a section of DNA that is wrapped around a protein core made up of eight histone molecules

histones

a small protein molecule that provides structural support for a chromosome

sister chromatids

the identical copies (chromatids) formed by the DNA replication of a chromosome; eventually separated during mitosis or meiosis II

cleavage furrow

an indentation that appears in a cell's surface when the cell is preparing to divide

cancer

disease caused when cells divide uncontrollably and spread into surrounding tissues; forms tumors

tumor

an abnormal mass of cells that forms within otherwise normal tissue

spermatogenesis

the formation of sperm cells in the testis

oogenesis

formation of egg cells in the ovaries

gamete

a sex cell; a haploid egg or sperm

genes

A heritable unit of DNA

alleles

Variants/forms of the same gene (blue, green, brown eye color)

karyotype

all the chromosomes in a cell

autosomes

any chromosome other than the sex chromosomes

sex chromosomes

a chromosome that determines whether an individual is male or female

nucleotide

the basic building block of nucleic acids (RNA and DNA)

polynucleotide strand

a polymer made up of many nucleotides covalently bonded together

deoxyribose

a pentose (5-carbon sugar) biological molecule

nucleic acid

consists of many nucleotide monomers; serves as a blueprint for proteins and, through the actions of proteins, for all cellular structures and activities; two types are DNA & RNA

deoxyribo nucleic acid (DNA)

the molecule that carries genetic information for the development and functioning of an organism

nitrogenous base

nitrogenous compounds that form an important part of the nucleotides

adenine

a double-ring nitrogenous base found in DNA and RNA (A pairs with T)

thymine

a single-ring nitrogenous base found in DNA (T pairs with A)

cytosine

a single-ring nitrogenous base found in DNA and RNA (pairs with G)

guanine

a double-ring nitrogenous base found in DNA and RNA (pairs with C)

purine

double carbon rings, include adenine and guanine, which participate in DNA and RNA formation

pyrimidine

single carbon rings, include cytosine and thymine

5’ phosphate group

a phosphorus atom bound to four oxygen atoms

3’ hydroxyl group

the hydrogenated oxygen molecule attached to the 3'; binds to 5’ phosphate group

double helix

the form assumed by DNA in living cells, referring to its two adjacent polynucleotide strands wound into a spiral shape

base pairing

consists of two complementary DNA nucleotide bases that pair together to form a “rung of the DNA ladder.” ([Purines] = [Pyrimidines], [A] = [T] and [G] = [C])

antiparallel

the strands run in opposite directions, parallel to one another

complementary

in a double strand of DNA, adenine will always pair with its complement thymine and cytosine will always pair with its complement guanine

heredity

the transmission of traits/characters from one generation to the next

genetics

the scientific study of heredity—of how certain qualities or traits are passed from parents to offspring as a result of changes in DNA sequence

traits

a variant of a character found within a population, such as purple flowers in pea plants or blue eyes in people

phenotype

physical expression of trait (purple or white flowers)

genotype

genetic (allelic) makeup of individual for specific trait (PP, Pp, pp)