Topic 2 Definitions Flashcards
What does Fick’s Law of Diffusion relate the rate of diffusion to?
Concentration difference, surface area, and membrane thickness
Fick’s Law can be expressed with the equation: Rate of diffusion ∝ (Membrane surface area x Concentration difference) / Membrane thickness.
What are alveoli?
Small air sacs found in the lungs that provide a large surface area for gas exchange
Alveoli are crucial for efficient gas exchange in the respiratory system.
What does the fluid mosaic model describe?
Membrane structure as a sea phospholipids in a bilayer studded with various proteins
This model illustrates the dynamic nature of cell membranes.
Define hydrophilic.
A molecule which is attracted to water
Hydrophilic molecules typically dissolve well in water.
Define hydrophobic.
A molecule which repels water
Hydrophobic molecules do not mix well with water and are often nonpolar.
What is a phospholipid?
A type of lipid formed by the condensation of one molecule of glycerol, two molecules of fatty acid, and a phosphate group
Phospholipids are fundamental components of cell membranes.
Define osmosis.
The net movement of water molecules across a partially permeable membrane from high to low water concentration without the use of energy
Osmosis is crucial for maintaining cellular homeostasis.
What is active transport?
The active movement of substances from low concentration to high concentration using energy in the form of ATP
Active transport allows cells to accumulate necessary substances against their concentration gradient.
What is endocytosis?
The bulk uptake of substances into a cell by invagination of the membrane to form a vesicle trapping the substances inside the cell with the use of energy in the form of ATP.
Endocytosis is crucial for nutrient uptake and cellular communication.
What is exocytosis?
The bulk transport of substances out of a cell using a vesicle that fuses with the plasma membrane using energy in the form of ATP.
Exocytosis is important for secretion of hormones and neurotransmitters.
What is amniocentesis?
Sampling the amniotic fluid to determine the sex of the fetus or any abnormalities that may be present during development.
Amniocentesis is typically performed between the 15th and 20th weeks of pregnancy.
What is chorionic villus sampling?
Sampling the placenta to test for any genetic diseases that may be present in the developing fetus.
This procedure can be done earlier in pregnancy than amniocentesis.
What is cystic fibrosis (CF)?
An autosomal recessive genetic disorder which causes the production of excess thick mucus.
CF primarily affects the lungs and digestive system.
What is a dominant trait?
A trait which is present if an individual has at least one copy of the gene.
Dominant traits can mask the expression of recessive traits.
What is a gene?
A sequence of bases on a DNA molecule that codes for a sequence of amino acids in a polypeptide chain.
Genes are the basic units of heredity.
What is a genotype?
The genetic makeup of an organism.
Genotype determines potential traits but not necessarily the observable characteristics.
What is a heterozygote?
An organism which has two different versions of the same gene.
Heterozygotes can express dominant traits.
What is a homozygote?
An organism which has two of the same versions of a gene.
Homozygotes can be either dominant or recessive.
What is incomplete dominance?
A type of inheritance where a dominant allele does not completely mask the recessive allele and so the trait produced is a combination of both alleles.
An example is the blending of flower colors in snapdragons.
What is monohybrid inheritance?
A genetic cross between two homozygous organisms.
This type of inheritance focuses on a single trait.
What is a mutation?
A change in the sequence of bases in a DNA molecule.
Mutations can be beneficial, harmful, or neutral.
What is a phenotype?
The observable characteristics of an organism.
Phenotype results from the interaction of genotype and the environment.
What is pre-implantation genetic diagnosis (PGD)?
A method used to diagnose diseases before implantation of the embryo into the uterus.
PGD is often used in conjunction with in vitro fertilization.
What is prenatal testing?
Testing performed before childbirth to determine the overall health of the developing fetus.
Prenatal testing can include blood tests, ultrasounds, and genetic testing.
What is a recessive trait?
A trait which is only present when an individual has two copies of the gene and can be masked by a dominant gene.
What is an amino acid?
The monomers containing an amino group (NH2), a carboxyl group (COOH) and a variable R group that make up proteins.
Define polymers.
Molecules made from a large number of monomers joined together.
What are monomers?
The smaller units from which larger molecules are made.
What is a condensation reaction?
A type of reaction that joins two molecules together with the formation of a chemical bond involving the elimination of a molecule of water.
What is hydrolysis?
Breaking a chemical bond between two molecules involving the use of a water molecule.
What is a dipeptide?
Molecules formed by the condensation of two amino acids.
What is a polypeptide?
Molecules formed by the condensation of many amino acids.
What is an enzyme?
A protein molecule that acts as a biological catalyst and increases the rate of biochemical reactions.
What are fibrous proteins?
A class of long chain proteins that are generally insoluble in water and typically have structural roles.
What are globular proteins?
A class of spherical shaped proteins that are generally water soluble and typically have metabolic roles.
What is secondary structure in proteins?
The local interactions of the amino acids in the polypeptide chain.
What is tertiary structure?
The way that the whole protein folds to make a three dimensional structure.
What is a hydrogen bond?
A type of weak bond formed between an electropositive hydrogen and an electronegative atom like oxygen or nitrogen.
What is haemoglobin?
A type of conjugated globular protein used to transport oxygen that is made up of four polypeptide chains each containing a haem prosthetic group.
What is collagen?
A type of fibrous protein that provides strength to many different cell types and makes up connective tissues.
What are enzymes?
Biological catalysts that reduce activation energy
What is an intracellular enzyme?
An enzyme that works within cells
What is an extracellular enzyme?
An enzyme which works outside of cells
What does FRNA stand for?
Ribosomal RNA
What is ribosomal RNA (FRNA)?
A type of RNA that makes up ribosomes
What is a ribosome?
An organelle found in the cytoplasm of cells that carries out protein synthesis
