Cell Structure Flashcards

Flashcards based on Cell Structure lecture notes.

Who first observed cells using a microscope in 1665?

Robert Hooke

Who described plant tissue as being composed of cells in 1838?

Matthias Schleiden

Who made similar microscopic observations of animal tissue?

Theodor Schwann

Who popularized the concept of cell theory?

Robert Remak & Rudolf Virchow

What is the first tenet of cell theory?

All organisms are composed of cells.

What is the second tenet of cell theory?

Cells are the smallest living things.

What is the third tenet of cell theory?

Cells arise only from pre-existing cells.

Why are most cells relatively small?

Reliance on diffusion of substances in and out of cells.

What affects the rate of diffusion?

Surface area available, temperature, concentration gradient, and distance.

What happens to the surface area-to-volume ratio as a cell increases in size?

It decreases.

What is resolution in microscopy?

Minimum distance two points can be apart and still be distinguished as two separate points.

What type of microscope uses magnifying lenses with visible light?

Light microscope

What type of microscope uses a beam of electrons?

Electron microscope

Where is DNA located in prokaryotes and eukaryotes?

Nucleoid (Prokaryote) or nucleus (Eukaryote)

What are the simplest organisms?

Prokaryotic Cells

What domains are prokaryotes divided into?

Archaea & Bacteria

Where is the DNA present for prokaryotes?

In the nucleoid, organized as a circular chromosome

What do prokaryotic chromosomes interact with to assist in organization and packaging?

Nucleoid-associated proteins (NAPs)

What acts like a bacterial compass?

Magnetosomes

What are bacterial microcompartments bounded by?

A semipermeable protein shell

What size are prokaryotic ribosomes?

70S

What are prokaryotic ribosomes composed of?

Two subunits: 30S and 50S

What is the function of flagella?

Enable bacteria to move directionally

What is the function of pili (fimbriae)?

Enable attachment (between bacteria or bacteria-to-host)

What is the primary component of bacterial cell walls?

Peptidoglycan

What characterizes archaean cell walls?

Lack peptidoglycan

What are some eukaryotic traits of archaea?

Share some genetic and biochemical similarities with eukaryotes, particularly in their transcription and translation processes.

What is the function of Taq Polymerase?

It’s used in PCR due to their stability and efficiency at high temperatures.

What protein are flagella made of in prokaryotes?

Flagellin

What protein are flagella made of in eukaryotes?

Microtubules

What is the hallmark of eukaryotic cells?

Compartmentalization

What is compartmentalization achieved through in eukaryotic cells?

Membrane-bound organelles and endomembrane system

What extra components do plant cells have that are not usually present in other eukaryotic cells?

A cell wall (composed of cellulose), chloroplasts, and specialized vacuoles

Where does ribosomal RNA synthesis take place in the nucleus?

Nucleolus

What controls movement in and out of the nucleus?

Nuclear pores

What is the semi-solid fluid inside the nucleus where we find the chromatin and the nucleolus?

Nucleoplasm

What are ribosomes composed of?

Ribosomal RNA (rRNA)-protein complex

What are eukaryotic ribosomes also known as?

80S ribosomes

What is the endoplasmic reticulum?

An interconnected network of membranous sacs that synthesize and transport substances

What is the function of the rough endoplasmic reticulum (rER)?

Active in protein & glycoprotein synthesis

What is the function of the smooth endoplasmic reticulum (sER)?

Synthesis of certain lipids & carbohydrates, detoxification of toxins, storage, and creates membranes

What is the function of the Golgi apparatus?

Functions in packaging and distribution of molecules synthesized at one location and used at another

Where do lysosomes arise from?

Golgi apparatus

What is the function of lysosomes?

Recycle old organelles, or digest cells and foreign matter that the cell has engulfed by phagocytosis

What do proteasomes break down?

Abnormal/misfolded proteins and normal proteins no longer needed by the cell

What is the function of peroxisomes?

Detoxify harmful substances that enter the cells

What is the function of vacuoles?

Storage and turgor pressure

What is the function of the central vacuole in plant cells?

Turgor pressure

What is the function of mitochondria?

Oxidative metabolism

What cycle occurs in the mitochondrial matrix?

Tricarboxylic acid (TCA) cycle / Krebs Cycle

What is the function of chloroplasts?

Photosynthesis

What theory proposes that some present-day eukaryotic organelles evolved by a symbiosis between two free-living cells?

Endosymbiotic Theory

What are the two key organelles that Endosymbiotic Theory applies to?

Mitochondria and chloroplasts

What is the function of the cytoskeleton?

Supports the shape of the cell and keeps organelles in fixed locations

Name the three types of fibers that make up the cytoskeleton.

Microfilaments (actin filaments), Microtubules, and Intermediate filaments

What is the function of centrosomes?

Serves as the main microtubule organizing center (MTOC) of the animal cell, as well as a regulator of cell-cycle progression

What is the function of centrioles?

Involved in the organization of the mitotic spindle and in the completion of cytokinesis (division of cytoplasm).

What arrangement of microtubules do eukaryotic flagella and cilia have?

9 + 2 arrangement

What are eukaryotic cell walls made of in plants and protists?

Cellulose

What are eukaryotic cell walls made of in fungi?

Chitin

What do animal cells secrete to form a network around them?

Extracellular Matrix (ECM)

What is the function of glycolipids on cell surfaces?

Tissue-specific cell surface markers

What is the function of MHC proteins on cell surfaces?

Recognition of “self” and “nonself” cells by the immune system

What are adhesive junctions?

Mechanically attaches cytoskeletons of neighboring cells or cells to the ECM

What are tight junctions?

Connect the plasma membranes of adjacent cells in a sheet – no leakage

What are communicating junctions?

Chemical or electrical signal passes directly from one cell to an adjacent one

What are plasmodesmata?

Specialized openings in plant cell walls that connect the cytoplasm of adjoining cells

Does ribosomes exist in both prokaryotes and eukaryotes?

True

Which component is primarily responsible for the cell membrane's ability to form a physical barrier?

phospholipid bilayer

What is not a function of sER?

involved in protein synthesis

Enzymes contained in which structure break down worn-out organelles and bacteria?

Lysosomes

Which statement is incorrect regarding prokaryotic cells?

They lack a plasma membrane

Which of the following contains no DNA?

Golgi body

What does the presence of many mitochondria imply about a cell’s energy requirements?

It has a high demand for energy.

What is the primary component of bacterial cell walls?

Cell Wall

Robert Hooke

Who first observed cells using a microscope in 1665?

Matthias Schleiden

Who described plant tissue as being composed of cells in 1838?

Theodor Schwann

Who made similar microscopic observations of animal tissue?

Robert Remak & Rudolf Virchow

Who popularized the concept of cell theory?

What is the first tenet of cell theory?

All organisms are composed of cells.

What is the second tenet of cell theory?

Cells are the smallest living things.

What is the third tenet of cell theory?

Cells arise only from pre-existing cells.

Why are most cells relatively small?

Reliance on diffusion of substances in and out of cells.

What affects the rate of diffusion?

Surface area available, temperature, concentration gradient, and distance.

What happens to the surface area-to-volume ratio as a cell increases in size?

It decreases.

What is resolution in microscopy?

Minimum distance two points can be apart and still be distinguished as two separate points.

What type of microscope uses magnifying lenses with visible light?

Light microscope

What type of microscope uses a beam of electrons?

Electron microscope

Where is DNA located in prokaryotes and eukaryotes?

Nucleoid (Prokaryote) or nucleus (Eukaryote)

What are the simplest organisms?

Prokaryotic Cells

What domains are prokaryotes divided into?

Archaea & Bacteria

Where is the DNA present for prokaryotes?

In the nucleoid, organized as a circular chromosome

What do prokaryotic chromosomes interact with to assist in organization and packaging?

Nucleoid-associated proteins (NAPs)

What acts like a bacterial compass?

Magnetosomes

What are bacterial microcompartments bounded by?

A semipermeable protein shell

What size are prokaryotic ribosomes?

70S

What are prokaryotic ribosomes composed of?

Two subunits: 30S and 50S

What is the function of flagella?

Enable bacteria to move directionally

What is the function of pili (fimbriae)?

Enable attachment (between bacteria or bacteria-to-host)

What is the primary component of bacterial cell walls?

Peptidoglycan