MCAT Biology Terms/Definitions

Just biology!

Nucleolus

part of a eukaryotic cell which synthesizes rRNA

cristae

infolding of the mitochondria

autolysis

release of enzymes from a lysosome resulting in apoptosis

Smooth ER

Which organelle detoxifies certain drugs'/poisons

carbohydrates, phosphates, sulfates

what groups are often added by the golgi apparatus?

exocytosis

secretion pathway that goes Golgi - secretory vesical - cell membrane

Peroxisome

organelle that contains hydrogen peroxide - breaks down fatty acid chains via beta-oxidation, synthesizes phospholipids, contains enzymes for the pentose phosphate pathway

microfilaments, microtubules, intermediate filaments

3 components of the cytoskeleton

actin

what protein makes up microfilaments?

myosin

what interacts with microfilaments and ATP to cause muscle contractions

microfilaments

what element of the cytoskeleton plays a role in cytokinesis and is resistant to fracture and compression?

tubulin

what protein makes up microtubules

Microtubules

which type of cytoskeletal protein provides a pathway for kinesin and dynein to carry vesicles, makes up cilia and flagella, and are made by centrioles during mitosis

9 + 2 structure

what structure is seen in microtubules in eukaryotic organelles of motility

keratin, desmin, vimentin, lamins

what 4 types of proteins are often seen in intermediate filaments?

intermediate filaments

which type of cytoskeletal molecule is involved in cell-to-cell adhesion and structural regidity?

epithelial tissue, connective tissue, muscle tissue, nervous tissue

what are the 4 types of tissue in the body?

Epithelial tissue

what tissue covers the body/lines cavities, involved in absorption, secretion, and sensation, is usually polarized

basement membrane

the underlying layer of connective tissue that connects to the epithelial layer

parenchyma

the functional part of an organ usually composed of epithelial cells

lumen

hollow inside of an organ or tube

Simple Epithelia

epithelia with one layer of cells

stratified epithelia

epithelia with multiple layers

pseudostratified epithelia

epithelia with one layer that appear to have multiple

cuboidal

cube shaped epithelial cells

columnar

long and thin shaped epithelial cells

squamous

flat/scale shaped epithelial cells

Connective tissue

which tissue type contributes most to stroma, produces materials to form the extracellular matrix

bone, cartilage, tendons, ligaments, adipose tissue, blood

examples of connective tissues (6)

collagen and elastin

examples of materials in the extracellular matrix

nucleoid region

where DNA is concentrated in a prokaryotic cell

start translation with MET, similar RNA pols, associate DNA with histones

similarities between eukaryotes and archaea

circular chromosome, binary fission/budding, overall structure

similarities between prokaryotes and archaea

fimbriae

bacterial structures similar to cilia

bacterial ribosome

what is a common site of attack for antibiotics, as it is smaller than the eukaryotic equivalent

cocci

spherical bacteria

bacilli

rod-shaped bacteria

spirilli

spiral-shaped bacteria

aerotolerant anaerobes

okay with oxygen in the environment, but cannot use it for metabolism

safranin and crystal violet

which two stains are used in gram staining

purple

which color are gram positive cells?

gram positive cell walls

what type (gram) of bacterial wall has a thick layer of peptidoglycan and lipoteichoic acid?

gram negative cell walls

what type (gram) of bacterial wall has a thin layer of peptidoglycan, separated from the cell membrane by the periplasmic space? They also contain adjacent membranes with lipopolysaccharides

lipopolysaccharides

what component of gram negative cell membranes cause such a strong immune response in humans?

penicillin

which antibiotic targets cross linking of peptidoglycan to kill gram positive bacteria

chemotaxis

ability of a cell to detect chemical stimuli and move towards or away from it

filament, basal body, hook

what are the parts of a flagellum in a eukaryote?

flagellin

what material makes up the filament of a bacterial flagellum?

basal body

what part of a bacterial flagellum is the “motor”

hook

what part of the bacterial flagellum connects the other two parts and provides torque?

cell membrane

what part of a bacterium is used for electron transport chain/ATP generation

30S and 50S

which subunits are in a prokaryotic ribosome

40S and 60S

which subunits are in a eukaryotic ribosome?

binary fission

what reproductive process involved DNA replication followed by the cell membrane growing inwards to produce two identical daughter cells?

episome

special type of plasmid that can integrate into the genome of a bacterium

Transformation (bacterial recombination)

integration of foreign DNA into the host genome, common in gram negative rods, state of competence, often happens in times of starvation or high cell density

bacterial competence

a state where extracellular DNA can be taken up

overexpressing a protein of interest not usually expressed

use of transformation of bacteria in the lab

transformation efficiency

count the number of CFUs, divide by the mass of DNA

conjugation

transfer of genetic material between two bacterium using a conjugation bridge - unidirectional using sex pili on the “male” - requires plasmids with “sex factors”

Hfr (High frequency of recombination)

bacteria that have integrated sex factors into their genome

transduction

bacterial genetic recombination process that requires a vector

transposons

genetic elements capable of removing and inserting themselves into a genome - can disrupt genes

lag - exponential (log) - stationary - death

what are the 4 phases of bacterial growth seen in a typical growth curve?

capsid

what is the protein coat of a virus called?

non-enveloped

which type (enveloped or non-enveloped )viruses are harder to kill?

Capsid, nucleic acid, tail sheath, tail fibers

what are the 4 parts of a bacteriophage?

Positive sense RNA virus

what type of virus can be directly translated to functional proteins by Ribosomes

Negative sense RNA virus

what type of virus acts as a template for protein synthesis, and must carry an RNA replicase?

retrovirus

what type of virus is an enveloped, single stranded RNA virus that can integrate into the host DNA

extrusion

process in which a viral progeny are released by fusing with the cell membrane, leaving the host cell alive and in a productive cycle

Lytic cycle

cycle where bacteriophage maximizes reproduction without care for survival of the host cell - virulent

Lysogenic cycle

virus integrates into host genome as a provirus, replicating as the bacterium does - makes the bacterium less prone to superinfection

prions

subviral particle that converts a protein from an alpha helical structure to a beta pleated sheet, reducing solubility of the protein and causing protein aggregates to form

viroid

subviral particle that infects primarily plants and can silence genes, causing metabolic and structural damage

g1 stage

stage in cell cycle where cells create organelles for energy and protein production and increase their size

restriction point

what governs passage into S stage?

G2 stage

cell cycle stage where the cell passes through its second checkpoint, making sure replication was successful and there is enough cytoplasm and organelles for the daughter cells

p53

main protein controlling cell cycle arrest for DNA repair

cyclins and cyclin-dependent kinases (CDKs)

molecules responsible for the cell cycle - phosphorylate transcription factors as a complex to promote genes that are transcribed to start the next phase of the cycle

TP53

common mutation to p53 found in cancer

aster

star-like appearance of centrosome and associated microtubules

meiosis 1

process resulting in homologous chromosomes being separated, generating haploid daughter cells - reductional division

Meiosis 2

process resulting in the separation of sister chromatids without a change in ploidy - equational division

synaptonemal complex

proteins that hold together homologous chromosomes during prophase 1 of meiosis

SRY (sex-determining region Y)

what gene on the Y chromosome encodes a transcription factor that initiates testis differentiation

SEVEN-UP (seminiferous tubules - epididymis - vas deferens - ejaculatory duct - N - urethra - penis)

What is the pathway of sperm through the male reproductive system?

Sertoli cells

cells in the seminiferous tubules that nourish sperm

interstitial cells of Leydig

what cells in the male reproductive organs secrete testosterone?

seminal fluid (fructose, alkaline properties, clear viscous fluid), and sperm

what are the components of semen

spermatogonia - primary spermatocytes - secondary spermatocytes - spermatids - spermatozoa

what is the process of maturity of sperm (5 steps)?

acrosome

cap of a sperm head, derived from golgi apparatus

peritoneal sac

sac that lines the female abdominal cavity

oogenia - primary oocytes (happens by birth) - secondary oocytes (stay in metaphase 2 until fertilization

Process of maturity of eggs

gonadotropin-releasing hormone

what hormone triggers the start of puberty - released by the hypothalamus triggering folicle-stimulating hormone (FSH) and luteinizing hormone (LH)

FSH

what hormone causes stimulates the sertoli cells and triggers sperm maturation in males and causes estrogens to be secreted in females?

LH

What hormone causes the interstitial cells to produce testosterone in males and causes progesterone release from the corpus luteum in females?

human chorionic gonadotropin (hCG)

what hormone maintains the corpus luteum if fertilization occurs, acting as an LH analog?

ampulla

widest part of the fallopian tube where fertilization occurs

acrosomal apparatus

tube-like structure that forms between the first sperm and the secondary oocyte’s cell membrane - penetrates the cell and allows pronucleus to enter