Cells and Basic Genetics

why is understanding cellular form and function important

to know how cells communicate, transport substances, generate energy, respond to energy, explain disease processes and guide clinical decision-making

what are the aspects of the modern cell theory

all organisms composed of cells, cell is simplest structural and functional unit of life, organisms structure and functions due to cell activities, cells only come from preexisting ones, cells have fundamental similarities

what are common cell shapes

squamous, cuboidal, columnar, discoid, stellate, fibrous

why is cell size limited

cell growth increases volume faster than surface area so absorption/removal of nutrients and waste removal are slowed down

what are the main components of the plasma membrane

phospholipid bilayer, proteins, cholesteral, and carbs

what is the purpose of the plasma membrane

defines cell bounderies, controls interactions with other cells, protects, and controls passage of materials in and out of the cell

what makes up 98% of the plasma membrane

lipids

how much of the phospholipid bilayer is composed of lipids

75%

what do the phospholipids allow the membrane to achieve

heads and tails create molecular motion that creates membrane fluidity

what is the purpose of cholesterol in the plasma membrane

affects membrane fluidity by adding structural stability, reducing passive permeability, signal transduction and most importantly, membrane fusion

what is the purpose of glycolipids in the plasma membrane

contribute to glycocalyx and maintain stability, cell-cell communication, and act as markers for immune responses

how much of the plasma membrane do proteins make up

2% but 50% of its weight

pass completely through the membrane and most are glycoprotiens

transmembrane proteins

adhere to membrane surface and are anchored to cytoskeleton

peripheral proteins

how cell communication occurs during chemical signals; they bind to a specific chemical like hormones

membrane receptors

receptors bind various chemicals through attachment of receptor-specific ligands that cause a change in shape by opening or closing; changes permeability to some substances

channel proteins

always open channels and is responsible for the permeability of the plasma membrane to ions when membrane is at rest

nongated ion channels

can be open or closed and may be a ligand (open to molecules binded to proteins) or voltage-gated (open to a change in charge across membrane

gated ion channels

acts to catalyze reactions at the outer or inner surface of membrane

enzymes

integral proteins that move ions from one side of the membrane to the other; have specific binding states that changes shape to take the molecule in

carrier proteins

carriers that consume ATP

pumps

acts as a cell's identity tag so it is able to identify "self" from foreign invaders

glycoproteins

the carb portion of glycoproteins and lipids that are unique in everyone besides twins

glycocalyx

what are the roles of glycocalyx

protection, immunity, defense against cancer, transplant compatibility( blood type antigens), cell adhesion, fertilization, and embryonic development

finger-like projections that act as an extension of the plasma membrane to increase the surface area to aid in absorption

microvilli

autoimmune disorder that destroys the microvilli in the small intestine

celiac

hairlike processes found on nearly every cell and act as sensory in inner ear, retina, and nasal cavity;

cilia

how do motile cilia work, like in the respiratory tract

beat in waves with a power stroke followed by recovery stroked to prevent things like mucus from falling back down

no ATP required; movement down concentration gradient: filtration and simple diffusion

passive membrane transport

requires ATP; movement against concentration gradient and is achieved through carriers (facilitated diffusion and active transport)

active transport

passing back and forth of molecules between the inside and outside of cell and depends on pressure differences on either side by hydrostatic pressure (greater to lower)

filtration

movement of solutes from higher to lower concentration in solution

diffusion

what diffuses through the lipid bilayer

nonpolar, hydrophobic substances

what diffuses through channel proteins

water and charged hydrophilic solutes

diffusion of water through a selectively permeable membrane; area of more water to less; through aquaporins that are specialized for this

osmosis

solutions with the same concentrations of solute particles

isosmotic

hyperosmotic

solution with a greater concentration of solute

hypoosmotic

solution with a lesser concentration of solute

ability of a solution to affect fluid volume and pressure within a cell and depends on the concentration and permeability of solute

tonicity

low concentration of non-permeating solutes (high water concentration) so cells absorb water and may burst (lyse)

hypotonic solution

high concentration of non-permeating solutes (low water concentration) so cells lose water and shrivel

hypertonic solution

normal saline

isotonic solution

transport of solute across membrane down its concentration gradient without using ATP; solute binds to carrier, changes shape and then releases solute on other side of membrane

facilitated diffusion

requires ATP to transport solute across membrane against its concentration gradient; rate of transport depends on concentration of substrate and the concentration of ATP

primary active transport

what are the functione of the sodium and potassium pump

regulation of cell volume, heat production, and maintenance of a membrane potential in all cells

no ATP used and instead uses nrg stored in ion gradients; ions move in same (symport) or different (antiport) direction

secondary active transport

what is an example of secondary active transport

sodium-glucose transporter (SGLT) in small intestine and kidney nephrons that moves glucose into cells against its concentration gradient by using the energy from sodium moving down its gradient

what are the two branches of vesicular transport

exocytosis and endocytosis

transports large particles or fluid through membrane in vesicles and uses ATP

vesicular transport

transport out of cell through vesicles; secreting material or replacement of plasma membrane; hormone release or immune responses

exocytosis

transport into cell

endocytosis

engulfs large particles, "cell-eating"; keeps tissues free of debris and infectious microorganisms

phagocytosis

takes in fluid droplets, "cell-drinking"; membrane caves in and then pinches off into the cytoplasm as a pinocytotic vesicle

pinocytosis

takes in specific molecules bound to receptors (ex. WBC engulf bacteria)

receptor mediated endocytosis

cellular material outside the nucleus but inside the plasma membrane; contains the organelles

cytoplasm

what organelles contain a membrane

nucleus, mitochondria, lysosome, peroxisome, ER, and Golgi

what organelles do not contain a membrane

ribosome, centrosome, centriole, basal bodies

largest membrane-bound organelle that contains a nuclear envelope and nucleoplasm for DNA and protein and produces ribosomes

nucleus

synthesis of packed proteins, phospholipids, and proteins of plasma membrane; abnormalities in genetic code can lead to tissue damage through mispackaged proteins; continuous with nuclear envelope and smooth ER

rough ER

lack ribosomes and responsible for synthesis of membranes, steroids, lipids, detoxification, and calcium storage

smooth ER

sites of protein synthesis by using mRNA to assemble amino acids specified in the DNA; target for medications and important for development of muscles and collagen; rare disorders if dysfunction

ribosomes

synthesizes carbs, packages proteins and glycoproteins for distribution by secretion or internal use

golgi complex

package of enzymes in a single unit membrane and is variable in shape

lysosomes

what are the functions of the lysosome

intracellular digestion of large molecules through autophagy and autolysis; also breakdown stored glycogen in liver to release glucose

neutralize free radicals, detoxify alcohol, drugs and toxins, use O2, H2O2 and catalase enzyme to oxidize organic molecules, breakdown fatty acids into acetyl groups

peroxisomes

site for ATP synthesis aerobically; increases in number when cell nrg requirements increase and contain DNA that codes for proteins needed

mitochondria

important for cell division and injury repair

centrioles

hold organelles in place, maintain cell shape, guide organelles inside cell; can be disassembled and reassembled

microtubules

collection of filaments and tubules that provide support, organization and movement

cytoskeleton

what is the cytoskeleton made of

microfilaments, intermediate fibers, microtubules

actin that forms network on cytoplasmic side of plasma membrane called the membrane skeleton

microfilaments

hold epithelial cells together; resist cell stress, line nuclear envelope, and toughens hair and nails

intermediate fibers

genetic makeup of an individual, the specific alleles individuals carry

gentotype

observable characteristics resulting from genotype and environment

phenotype

different versions of the same gene (dominant or recessive)

allele

identical dominant alleles (AA)

homozygous dominant

identical recessive alleles (aa)

homozygous recessive

two different alleles (Aa)

heterozygous carrier

percentage of individuals with a genetic variant who develop the associated condition

penetrance

function of DNA

roadmap for body processes and cellular structure; code for synthesis of RNA and protein; instructions for protein synthesis, cell regulation, and inheritance of traits

sequence of DNA nucleotides that codes for one protein

gene

all the genes of one person

genome

nucleotide structure

phosphate group, sugar (ribose for RNA and deoxyribose for DNA), nitrogenous base

what bases are found in DNA

CTAG

what bases are found in RNA

CUAG

what is the start codon

AUG

what is the stop codon

UAA, UAG, UGA

how does complementary base pairing occur

the nitrogenous bases are united by hydrogen bonds (A-T and C-G)

what are errors in DNA replication

mutations that can carry down family lines

cell division to increase the number of cells to create two genetically identical daughter cells from one parent; purpose is for growth and repair

mitosis

specialized cell division to produce gametes for sexual reproduction to create another life

meiosis

the 22 pairs of non sex chromosomes

autosomes

mapped entire base sequence of 99% of our DNA and goal is to sequence the entire genome

the human genome project

branch of biology that deals with inheritance

genetics

area of health care that offers advice on genetic problems

genetic counseling

permanent heritable change in a gene that causes it to have a different effect than previously

mutation

affects males and females equally and appears in every generation; one mutated gene copy causes disease

autosomal dominant

what are some examples of autosomal dominant hereditary

hereditary breast and ovarian cancer, marfan syndrome, polycystic kidney disease

affects males and females equally, two mutated gene copies required for disease, parents are usually unaffected carriers; 25% chance of getting if parents are carriers

autosomal recessive

examples of autosomal recessive

sickle cell, cystic fibrosis, tay sachs