MileDown MCAT Biology

Nucleoid region

DNA region in prokaryotes

Nucleolus

Makes ribosomes. Sit in nucleus, no membrane

Peroxisomes

collect and break down material

rough ER

accept mRNA to make proteins

smooth ER

detox and make lipids

golgi apparatus

modify/distribute proteins. only in eukaryotes

vesicular transport

Transport of large particles and macromolecules across plasma membranes

cisternal maturation

The process of cargo movement through the Golgi apparatus by residing in cisternae that mature from cis to trans via the import and export of different Golgi enzymes.

peroxisomes

collect and break down material

centrioles

9 groups of microtubules, pull chromosomes apart

lysosomes

demo and recycling center. made by golgi, single membrane

plasmids

in prokaryotes. Carry DNA. not necessary for survival

bacilli

Rod shaped bacteria

cocci

spherical bacteria

spirilla

spiral shaped bacteria

obligate aerobe

requires O2

obligate anaerobe

dies in the presence of oxygen

facultative anaerobe

toggle between aerobic/anaerobic

aerotolerant anaerobe

does not utilize oxygen but can survive and grow in its presence

gram positive bacteria

stains purple

gram negative bacteria

stains pink/red

gram positive bacteria

thick peptidoglycan/lipoteichoic acid cell wall

gram negative bacteria

thin peptidoglycan cell wall and an outer membrane

eukaryote

ETC in mitochondria

large ribosomes

reproduce via mitosis

prokaryote

ETC in cell membrane

small ribosomes

reproduce via binary fission

plasmids carry DNA material. May have virulence factors.

virulence factors

traits of a microbe that promote pathogenicity

episomes

plasmids that can integrate into the genome

prions

infections proteins. Trigger misfolding, alpha-helical --> beta pleated sheets. decreases solubility

viroid

plant pathogens

actin

thin filaments

tubulin

protein that makes up microtubules

intermediate filaments

keratin (vimentin); desmin (lamin)

parenchyma

functional tissues of any organ, such as the tissues of the bronchioles, alveoli, ducts, and sacs, that perform respiration

simple epithelia

one layer of cells

stratified epithelia

multiple layers

pseudostratified epithelia

one layer but looks like more

cuboidal epithelia

cube shaped cells

columnar epithelia

long and narrow cells

squamous epithelia

flat, scale-like cell

stroma

the supportive tissue of an epithelial organ, tumor, gonad, etc., consisting of connective tissues and blood vessels.

transformation

A change in genotype and phenotype due to the assimilation of external DNA by a cell.

conjugation

transfer of genetic info via conjugation bridge. F+ --> F- or Hfr --> recipient

transduction

transfer using bacteriophage

Transposons

genetic elements capable of inserting and removing themselves from the genome

capsid

protein coat

envelope

some viruses have this additional surrounding lipid bilayer membrane

virion

complete virus particle

bacteriophage

A virus that infects bacteria

viral genome

may be DNA or RNA. Single or double stranded

positive sense

single strand - can be translated by host cell

negative sense

single strand - RNA replicase must synthesize a complimentary strand, which can then be translated

Retrovirus

single stranded RNA. Reverse transcriptase needed to make DNA

lytic cycle

Bacteriophage life cycle in which the virus takes over the operation of the bacterium immediately upon entering it makes virions until cell lyses

lysogenic cycle

Bacteriophage life cycle in which the virus integrates into genome as provirus or prophage. Goes dormant until stress activates it.

G1

make mRNA and proteins to prep for mitosis

G0

a cell will enter this phase if it does not need to divide

G1 checkpoint

cell decides if it should divide. P53 is in charge

S1

phase where DNA is replicated

G2

phase where cell grows and makes organelles

G2 checkpoint

cell size and organelles

M

phase where mitosis and cytokinesis occurs

prophase

DNA condenses, centrioles migrate to opposite poles, microtubules form, nuclear envelope disappears

metaphase

Chromosomes line up in the middle of the cell

anaphase

The sister chromatids separate into individual chromosomes and are moved apart.

telophase

chromosomes decondense, nuclear membrane forms, cytokinesis occurs.

nondisjunction

when sister chromatids dont separate properly during anaphase

aneuploidy

Abnormal number of chromosomes.

aneuploidy

occurs as a result of nondisjunction

prophase 1

chromosomes condense, nuclear membrane dissolves, homologous chromosomes form bivalents, crossing over occurs

bivalents

a pair of homologous chromosomes

crossing over

Process in which homologous chromosomes exchange portions of their chromatids during meiosis.

metaphase 1

spindle fibers from opposing centrosomes connect to bivalents at centromeres and align them along the middle of the cell

anaphase 1

homologous pairs move to opposite poles of the cell. This is disjunction and it accounts for the law of segregation

disjunction

the separation of homologous pairs of chromosomes following meiotic synapsis

Law of Segregation

Mendel's law that states that the pairs of homologous chromosomes separate in meiosis so that only one chromosome from each pair is present in each gamete

telophase 1

chromosomes decondense, nuclear membrane may reform, cell divides (cytokinesis), forms two haploid daughter ceells of unequal sizes

prophase 2

chromosomes condense, nuclear membrane dissolves, centrosomes move to opposite poles (perpendicular to before)

metaphase 2

spindle fibers from opposing centrosomes attach to chromosomes (at centromere) and align them along the cell equator

anaphase 2

spindle fibers contract and separate the sister chromatids, chromatids (now called chromosomes) move to opposite poles

telophase 2

chromosomes decondense, nuclear membrane reforms, cell divide (cytokinesis) to form four haploid daughter cells

semen

sperm + seminal fluid

bulbourethral glands

makes viscous fluid to clean out urethra

seminal vesicles

two small glands that secrete a fluid rich in sugar that nourishes and helps sperm move

prostate gland

a gland surrounding the neck of the bladder in male mammals and releasing prostatic fluid.

seminiferous tubules

site of spermatogenesis. nourished by sertoli cells

epididymis

stores sperm. sperm gain motility

vas deferens

raise/lower testes

ovaries

have follicles that produce ova. Controlled by FSH and LH

oogenesis

production of female gametes

estrogen

response to FSH. develops rep tract, thickens uterine wall

progesterone

response to LH, maintains/protects endometrium.

FSH

follicle stimulating hormone. triggers spermatogenesis in males and stimulates sertoli cells. In females, stimulates development of ovarian follicesl.

LH

in males, causes interstitial cells to make testosterone. In females, induces ovulation

ectoderm

nervous system, skin, hair, nails, mouth, anus

mesoderm

musculoskeletal system, circulatory system, gonads, adrenal cotex.

endoderm

endocrine glands, GI tract, respiratory tract, bronchi, bladder, stomach

notochord

mesoderm develops a _______ which induces ectoderm

dizygotic

fraternal twins

monozygotic

identical twins

determination

The point during development at which a cell becomes committed to a particular fate due to cytoplasmic effects or to induction by neighboring cells.