NLN-PAX Science Exam Questions and
answers 2025
Cell .- .ANS✓✓-
the .smallest .living .unit .and .the .basic .unit .of .function .and .structure .for .all .living
.things.
Nucleus .- .ANS✓✓-
contains .the .genetic .information, .or .DNA, .and .controls .the .activities .of .the .cell.
Plasma .(cell) .membrane .- .ANS✓✓-
separates .the .contents .of .the .cell .from .the .surrounding .fluid .(interstitial .fluid)
Semipermeable .membrane .- .ANS✓✓-
refers .to .the .selective .nature .of .the .plasma .membrane. .It .contains .pores .and .ch
annels .that .allow .only .particles .of .the .right .size .or .the .right .chemical .nature .to .
pass .through.
Interstitial .fluide .- .ANS✓✓-
contains .substances .such .as .amino .acids, .sugars, .fatty .acids, .hormones, .neuro
transmitters, .and .salts.
Cytoplasm .- .ANS✓✓-
is .the .fluid .matrix .found .between .the .plasma .membrane .and .the .nucleus .that .a
cts .as .scaffolding .for .the .organelles.
Organelles .- .ANS✓✓-
(little .organs) .are .specialized .units .in .the .cell .that .per .form .certain .functions.
Mitochondria .- .ANS✓✓-
are .the .locations .for .cellular .respiration, .that .is, .the .conversion .of .food .to .ener
gy .at .the .cellular .level. .The .site .of .energy .production .and .of .most .of .its .ATP.
ATP .(adenosine .triphosphate) .- .ANS✓✓-
the .chemical .the .cell .uses .to .store .and .transfer .energy .within .itself.
Ribosomes .- .ANS✓✓-are .the .sites .of .protein .synthesis .in .the .cell
Endoplasmic .reticulum .(ER) .- .ANS✓✓-
Ribosomes .are .attached. .Serves .as .a .means .for .transport .within .the .cell .and .is .
,made .up .of .many .channels. .Rough .endoplasmic .reticulum .named .for .the .fact .t
hat .it .has .ribosomes .on .its .surface, .serves .to .store .and .deliver .the .proteins .ma
de .by .the .attached .ribosomes. .Smooth .ER .is .free .of .ribosomes .it .performs .vary
ing .functions .in .different .cells, .including .the .storage .of .enzymes .and .minerals .
and .the .folding .of .proteins, .among .other .things. .It .is .thought .to .be .involved .in .t
he .detoxification .of .chemicals .and .the .metabolism .of .fats.
Golgi .complex .- .ANS✓✓-
modifies .and .packages .proteins .destined .for .use .in .the .cell .or .for .export .from .t
he .cell.
Lysosomes .- .ANS✓✓-
are .sacs .that .contain .strong .digestive .enzymes. .These .sacs .are .responsible .for
.digesting .cell .structures .that .are .no .longer .living .or .that .are .malfunctioning, .an
d .for .digesting .waste.
Cell .wall .- .ANS✓✓-
Only .plant .cells .have .them. .It .is .responsible .for .the .protection .of .the .cell, .the .m
aintenance .of .the .shape, .and .water .balance.
Chloroplasts .- .ANS✓✓-
contain .chlorophyll, .which .is .necessary .for .photosynthesis.
Vacuoles .- .ANS✓✓-
plant .cells .also .often .large .ones. .Which .are .compartments .in .the .cytoplasm .tha
t .act .as .places .for .secretion, .excretion, .and .storage.
Chromatin .- .ANS✓✓-
DNA .is .in .this .loosely .structured .form .when .it .is .not .dividing
Chromosomes .- .ANS✓✓-DNA .is .seen .in .condensed .rod-
shaped .bodies .when .the .cell .is .dividing
Mitosis .- .ANS✓✓-
When .cells .divide, .the .appropriate .amount .of .genetic .material .must .be .passed .
on .to .the .new, .or .so-called .daughter, .cells. .In .somatic .
(non .reproductive) .cells, .the .new .cells .are .identical .copies .of .the .parent .cells. .T
his .is .achieved .by .a .doubling .of .the .chromosomes .prior .to .division. .It .is .useful
.in .the .growth .and .repair .of .our .bodies.
Zygote .- .ANS✓✓-
the .cell .created .by .the .union .of .a .sperm .and .egg .contains .a .full .set .of .chromos
omes, .half .from .each .parent.
Meiosis .- .ANS✓✓-
Another .type .of .division .takes .place .in .the .production .of .gametes. .It .contains .h
alf .of .the .normal .number .of .chromosomes. .It .consists .first .of .doubling .of .chro
mosomes .and .then .two .subsequent .divisions. .Thus .the .products .are .four .daug
hter .cells, .each .with .half .the .normal .number .of .chromosomes.
, Muscle .tissue .- .ANS✓✓-skeletal, .cardiac, .and .smooth
Epithelial .tissue .- .ANS✓✓-skin, .the .lining .of .organs
Nervous .tissue .- .ANS✓✓-neurons
Connective .tissue .- .ANS✓✓-cartilage, .blood, .fat, .bone
Organ .- .ANS✓✓-performs .a .specialized .function .in .the .body.
Organ .system .- .ANS✓✓-
made .up .of .a .number .of .organs .working .together .to .carry .out .a .major .function.
Organism .- .ANS✓✓-the .highest .level .of .organization .such .as .the .human .body
Evolution .- .ANS✓✓-
is .a .theory .regarding .the .processes .that .have .produced .the .biological .diversity .
we .see .today.
Natural .selection .- .ANS✓✓-
the .process .by .which .the .traits .that .promote .or .enhance .an .organism's .ability .t
o .survive .and .reproduce .are .passed .on .to .following .generations.
Adaptation .- .ANS✓✓-
For .natural .selection .to .occur, .organisms .must .have .variations, .some .of .which .
give .the .individuals .having .them .an .advantage .in .the .struggle .for .survival. .The .
struggle .for .survival .occurs .because .each .generation .of .a .species .produces .mo
re .offspring .than .can .survive. .In .this .struggle, .the .individuals .best .suited .to .the
ir .environment .survive .
("survival .of .the .fittest") .and .pass .on .the .traits .to .their .offspring
Fossil .record .- .ANS✓✓-
consists .of .remnants .or .traces .of .organisms .from .past .geologic .ages.
Vertebrates .- .ANS✓✓-animals .with .backbones
Biogeography .- .ANS✓✓-the .geographical .distribution .of .plants .and .animals
Comparative .anatomy .- .ANS✓✓-the .comparison .of .organisms' .structures
Comparative .embryology .- .ANS✓✓-the .comparison .of .organisms' .embryos
Molecular .biology .- .ANS✓✓-biology .at .the .molecular .level
Taxonomy .- .ANS✓✓-
the .study .of .scientific .classification. .Species .are .grouped .according .to .their .si
milarities .and .differences.
answers 2025
Cell .- .ANS✓✓-
the .smallest .living .unit .and .the .basic .unit .of .function .and .structure .for .all .living
.things.
Nucleus .- .ANS✓✓-
contains .the .genetic .information, .or .DNA, .and .controls .the .activities .of .the .cell.
Plasma .(cell) .membrane .- .ANS✓✓-
separates .the .contents .of .the .cell .from .the .surrounding .fluid .(interstitial .fluid)
Semipermeable .membrane .- .ANS✓✓-
refers .to .the .selective .nature .of .the .plasma .membrane. .It .contains .pores .and .ch
annels .that .allow .only .particles .of .the .right .size .or .the .right .chemical .nature .to .
pass .through.
Interstitial .fluide .- .ANS✓✓-
contains .substances .such .as .amino .acids, .sugars, .fatty .acids, .hormones, .neuro
transmitters, .and .salts.
Cytoplasm .- .ANS✓✓-
is .the .fluid .matrix .found .between .the .plasma .membrane .and .the .nucleus .that .a
cts .as .scaffolding .for .the .organelles.
Organelles .- .ANS✓✓-
(little .organs) .are .specialized .units .in .the .cell .that .per .form .certain .functions.
Mitochondria .- .ANS✓✓-
are .the .locations .for .cellular .respiration, .that .is, .the .conversion .of .food .to .ener
gy .at .the .cellular .level. .The .site .of .energy .production .and .of .most .of .its .ATP.
ATP .(adenosine .triphosphate) .- .ANS✓✓-
the .chemical .the .cell .uses .to .store .and .transfer .energy .within .itself.
Ribosomes .- .ANS✓✓-are .the .sites .of .protein .synthesis .in .the .cell
Endoplasmic .reticulum .(ER) .- .ANS✓✓-
Ribosomes .are .attached. .Serves .as .a .means .for .transport .within .the .cell .and .is .
,made .up .of .many .channels. .Rough .endoplasmic .reticulum .named .for .the .fact .t
hat .it .has .ribosomes .on .its .surface, .serves .to .store .and .deliver .the .proteins .ma
de .by .the .attached .ribosomes. .Smooth .ER .is .free .of .ribosomes .it .performs .vary
ing .functions .in .different .cells, .including .the .storage .of .enzymes .and .minerals .
and .the .folding .of .proteins, .among .other .things. .It .is .thought .to .be .involved .in .t
he .detoxification .of .chemicals .and .the .metabolism .of .fats.
Golgi .complex .- .ANS✓✓-
modifies .and .packages .proteins .destined .for .use .in .the .cell .or .for .export .from .t
he .cell.
Lysosomes .- .ANS✓✓-
are .sacs .that .contain .strong .digestive .enzymes. .These .sacs .are .responsible .for
.digesting .cell .structures .that .are .no .longer .living .or .that .are .malfunctioning, .an
d .for .digesting .waste.
Cell .wall .- .ANS✓✓-
Only .plant .cells .have .them. .It .is .responsible .for .the .protection .of .the .cell, .the .m
aintenance .of .the .shape, .and .water .balance.
Chloroplasts .- .ANS✓✓-
contain .chlorophyll, .which .is .necessary .for .photosynthesis.
Vacuoles .- .ANS✓✓-
plant .cells .also .often .large .ones. .Which .are .compartments .in .the .cytoplasm .tha
t .act .as .places .for .secretion, .excretion, .and .storage.
Chromatin .- .ANS✓✓-
DNA .is .in .this .loosely .structured .form .when .it .is .not .dividing
Chromosomes .- .ANS✓✓-DNA .is .seen .in .condensed .rod-
shaped .bodies .when .the .cell .is .dividing
Mitosis .- .ANS✓✓-
When .cells .divide, .the .appropriate .amount .of .genetic .material .must .be .passed .
on .to .the .new, .or .so-called .daughter, .cells. .In .somatic .
(non .reproductive) .cells, .the .new .cells .are .identical .copies .of .the .parent .cells. .T
his .is .achieved .by .a .doubling .of .the .chromosomes .prior .to .division. .It .is .useful
.in .the .growth .and .repair .of .our .bodies.
Zygote .- .ANS✓✓-
the .cell .created .by .the .union .of .a .sperm .and .egg .contains .a .full .set .of .chromos
omes, .half .from .each .parent.
Meiosis .- .ANS✓✓-
Another .type .of .division .takes .place .in .the .production .of .gametes. .It .contains .h
alf .of .the .normal .number .of .chromosomes. .It .consists .first .of .doubling .of .chro
mosomes .and .then .two .subsequent .divisions. .Thus .the .products .are .four .daug
hter .cells, .each .with .half .the .normal .number .of .chromosomes.
, Muscle .tissue .- .ANS✓✓-skeletal, .cardiac, .and .smooth
Epithelial .tissue .- .ANS✓✓-skin, .the .lining .of .organs
Nervous .tissue .- .ANS✓✓-neurons
Connective .tissue .- .ANS✓✓-cartilage, .blood, .fat, .bone
Organ .- .ANS✓✓-performs .a .specialized .function .in .the .body.
Organ .system .- .ANS✓✓-
made .up .of .a .number .of .organs .working .together .to .carry .out .a .major .function.
Organism .- .ANS✓✓-the .highest .level .of .organization .such .as .the .human .body
Evolution .- .ANS✓✓-
is .a .theory .regarding .the .processes .that .have .produced .the .biological .diversity .
we .see .today.
Natural .selection .- .ANS✓✓-
the .process .by .which .the .traits .that .promote .or .enhance .an .organism's .ability .t
o .survive .and .reproduce .are .passed .on .to .following .generations.
Adaptation .- .ANS✓✓-
For .natural .selection .to .occur, .organisms .must .have .variations, .some .of .which .
give .the .individuals .having .them .an .advantage .in .the .struggle .for .survival. .The .
struggle .for .survival .occurs .because .each .generation .of .a .species .produces .mo
re .offspring .than .can .survive. .In .this .struggle, .the .individuals .best .suited .to .the
ir .environment .survive .
("survival .of .the .fittest") .and .pass .on .the .traits .to .their .offspring
Fossil .record .- .ANS✓✓-
consists .of .remnants .or .traces .of .organisms .from .past .geologic .ages.
Vertebrates .- .ANS✓✓-animals .with .backbones
Biogeography .- .ANS✓✓-the .geographical .distribution .of .plants .and .animals
Comparative .anatomy .- .ANS✓✓-the .comparison .of .organisms' .structures
Comparative .embryology .- .ANS✓✓-the .comparison .of .organisms' .embryos
Molecular .biology .- .ANS✓✓-biology .at .the .molecular .level
Taxonomy .- .ANS✓✓-
the .study .of .scientific .classification. .Species .are .grouped .according .to .their .si
milarities .and .differences.
