The World of Cell and Cell Division

A set of fill-in-the-blank practice flashcards covering cell basics, cell theory, prokaryotic vs. eukaryotic structures, cytoplasmic organelles, plant vs. animal cell features, and the stages of cell division (mitosis and meiosis).

The unit mass of protoplasm, defined as the lowest level of organization capable of performing life processes, is the __________

cell

The study of cell structures, functions, and composition is known as __________

cytology

The smallest microscopic cell sizes reach __________ in bacteria

$$250\,\text{m}\mu$$

In 1665, __________ observed cork slices under a microscope and named the empty compartments 'cellae'

Robert Hooke

The living substance contained within cell chambers was discovered by Felix Dujardin and named __________

protoplasm

The discovery of the cell nucleus is attributed to __________

Robert Brown

Matthias Schleiden and Theodor Schwann formulated the first statement of the Cell Theory, while __________ added the second statement (omnis cellula e cellula)

Rudolf Virchow

While prokaryotic cells have naked DNA structure, eukaryotic cells have DNA combined with __________

proteins

Prokaryotic cell division occurs through amitosis, whereas eukaryotic cell division occurs through __________

mitosis and meiosis

The chemical composition of the cell membrane consists of $55\%$ proteins, $3\%$ carbohydrates, and __________ lipids

$$42\%$$

The protein layer responsible for elasticity in the cell membrane contains __________ protein

tectin

While most cells contain $1$ nucleus, mature RBCs, platelets, and eye lens cells contain __________ nuclei

$$0$$

The double-walled nuclear membrane (karyotheca) features a gap of __________ and has an inner lining containing the fibrous nuclear lamina

$$20-40\,\text{nm}$$

The site of ribosomal RNA (rRNA) synthesis and ribosome subunit assembly in the nucleus is the __________

nucleolus

Ribosomes, also called microsomes, are composed of $65\%$ RNA and __________ protein

$$35\%$$

The Golgi apparatus (dictyosomes) was discovered in 1898 by __________

Camillo Golgi

The Smooth Endoplasmic Reticulum (SER) synthesizes lipids, breaks down glycogen in the liver, and stores __________ ions

$$\text{Ca}^{2+}$$

Mitochondria increase their surface area for ATP production through inner membrane foldings called __________

cristae

Lysosomes contain approximately $40$ digestive enzymes, including acid hydrolase and __________

lysozyme

Peroxisomes contain oxidases and catalase to produce and break down hydrogen peroxide ($\text{H}_2\text{O}_2$), detoxify ethanol, and convert fats to __________

glucose

Centrioles (diplosomes) consist of paired self-duplicating cylinders made of $9$ microtubule __________

triplets

Vacuoles are storage cavities enclosed by a membrane known as the __________

tonoplast

In contrast to circular animal cells, plant cells have a rectangular shape and unique structures including plastids, a cell wall, and a large central __________

vacuole

The preparatory phase of the cell cycle that accounts for approximately $90\%$ of cycle time is __________

interphase

During the S phase of interphase, __________ unwinds the DNA double helix at the replication fork

DNA Helicase

Mitosis yields $2$ identical diploid ($2n$) somatic cells, which in humans contain __________ chromosomes

$$46$$

During Prophase I of meiosis, synapsis of homologous chromosomes occurs during the __________ stage

Zygotene

Crossing over and genetic recombination occur during the __________ stage of Prophase I at contact points called chiasmata

Pachytene

Meiosis I is classified as a reductional division, whereas Meiosis II is classified as an __________ division

equational

In gametogenesis, sperm creation is termed spermatogenesis, while egg creation is termed __________

Oogenesis