Cellular and Subcellular Structure and Function

Comprehensive fill-in-the-blank practice flashcards covering eukaryotic and prokaryotic cell biology, surface-area-to-volume ratios, organelle anatomy, endomembrane trafficking, and the endosymbiotic theory.

Cells typically range in size from one millimeter down to __________.

one micrometer

As a cell grows, its volume increases much faster than its __________.

surface area

A single $4\text{-cm}$ cube has a surface-area-to-volume ratio of $1.5:1$, whereas sixty-four $1\text{-cm}$ cubes of equal total volume have a ratio of __________.

$$6:1$$

Cells specialized in absorption utilize membrane modifications such as __________ to dramatically increase surface area per unit volume.

microvilli

To increase surface area and achieve larger sizes, cells may possess 'frilly' edges or long, narrow shapes, whereas __________ cells will always remain small.

round

The two primary classes of eukaryotic organelles are the __________ system and the energy-related organelles.

endomembrane

The plasma membrane is structurally composed of a double layer of __________ with embedded proteins.

phospholipids

The aqueous medium of the cell known as cytoplasm or cytosol consists primarily of water, making up __________ of its composition.

$$70\%-90\%$$

The endomembrane system consists of the nuclear envelope, the endoplasmic reticulum, the Golgi apparatus, and __________.

vesicles

The nucleus is the most prominent organelle in a eukaryotic cell, accounting for roughly __________ of the total cell volume.

$$10\%$$

All cells in the human body contain a nucleus except for mature red blood cells and the __________ layer of the skin.

uppermost

DNA controls an organism's traits following the pathway: $\text{DNA} \rightarrow \text{proteins} \rightarrow$ __________.

traits

A DNA nucleotide consists of a 5-carbon sugar (deoxyribose), a phosphate group, and a __________ base.

nitrogenous

In the nucleus, DNA exists as unwound thread-like chromatin or as condensed, coiled structures called __________.

chromosomes

Each nuclear pore embedded in the nuclear envelope is structurally formed by a ring of __________ proteins surrounding a central opening.

8

The jelly-like fluid matrix that is enclosed within the nuclear membrane is called the nucleoplasm or __________.

karyoplasm

The nucleolus is a non-membranous structure occupying about $25\%$ of the nuclear volume that synthesizes __________ and directs ribosome assembly.

rRNA

Ribosomes were first observed in 1953 by Romanian cell biologist __________.

George Emil Palade

The rough endoplasmic reticulum is studded with ribosomes on its cytoplasmic surface and adds sugar chains to proteins to form __________.

glycoproteins

In addition to synthesizing lipids like steroid hormones, the smooth endoplasmic reticulum functions in calcium storage and the __________ of organic compounds in liver cells.

detoxification

The Golgi apparatus consists of a stack of $3-20$ flattened, curved saccules that resemble a stack of __________.

hollow pancakes

Proteins and lipids from the ER enter the Golgi apparatus at its __________ face and exit packaged in vesicles from its trans face.

cis

Lysosomes were discovered in 1955 by Christian de Duve and are commonly referred to as '__________'.

suicide bags

A genetic absence of a lysosomal enzyme that degrades fatty acids causes a toxic accumulation of lipid substances in brain cells known as __________ disease.

Tay-Sachs

In plant cells, the large central vacuole may comprise up to $90\%$ of cellular volume and is primarily responsible for maintaining __________ pressure.

turgor

In chloroplasts, thylakoids are stacked into structures called __________, which maximize surface-area-to-volume ratio for photophosphorylation.

grana

The fluid-filled space within chloroplasts that contains enzymes and a suitable pH for the Calvin cycle is the __________.

stroma

The inner membrane of a mitochondrion is folded into finger-like projections called __________ to expand the surface area available for ATP synthesis.

cristae

The semi-fluid internal compartment of mitochondria containing enzymes for the Krebs cycle is known as the __________.

matrix

According to the Endosymbiotic Theory, mitochondria and chloroplasts contain __________ ribosomes, similar to those found in prokaryotes.

70S

The rigid plant cell wall is predominantly composed of __________ chains embedded in a matrix of other polysaccharides.

cellulose