Tour of the Cell

What was the first known microscope?

Light microscope

In terms of microscopes, what is resolution?

Measure of clarity

Who discovered cells in 1665?

Robert Hooke

“All living things are composed of cells and all cells come from other cells.”

This is known as….

Cell theory

Electron microscopes focus beams of electrons through or onto a specimen to capture its image. What are the two types of electron microscopes?

Scanning, transmission

Electron microscopes can distinguish specimens as small as _____ nanometers.

2

What do electron scanning microscopes do?

Produce 3D images from gold-coated specimens

What do electron transmission microscopes do?

Study the internal cell structure of a specimen stained with heavy metals

Electron microscopes can’t be used to study living specimens. Why?

The prep method kills the specimens

True or False: Cell function sets upper/lower limits on cell size.

True

A cell must be large enough to ________, but small enough to __________.

Fit all of its organelles, support surface area

What is the plasma membrane?

Boundary between cell and its surroundings

The plasma membrane is made up of ________.

phospholipids

The heads of phospholipids are… (2 traits)

Hydrophilic, negatively charged

The tails of phospholipids are… (3 traits)

Hydrophobic, nonpolar, made of fatty acids

The plasma membrane has ___________ embedded within it to aid molecular transport.

transport proteins

True or False: Prokaryotic cells were the only inhabitants of Earth for over 1.5 billion years.

True

The domains _______ and ________ are considered prokaryotes.

Bacteria, Archaea

Prokaryotic cells are not compartmentalized. What does this mean?

Their organelles are free-floating

Prokaryotic cell DNA is coiled into __________ that have no membrane.

nucleoids

True or False: Prokaryotic ribosomes are the target of antibiotics.

True

Prokaryotic fimbriae are…

attachment structures on the outer surface of the cell

What are pili?

Smaller, longer fimbriae in gram negative bacteria

The genetic information of prokaryotes, found in the nucleoid, is called…

bacterial chromosomes

The cell wall in bacteria is made up of…

peptidoglycan

The cell wall in archaea is made up of…

s-layers

In prokaryotes, what is a capsule?

Jellylike coating that protects the cell

Prokaryotic flagella are…

“Tail” that propels the cell

True or False: Eukaryotes evolved from prokaryotes.

True

What is the meaning of Eukarya?

True nucleus

What do eukaryotes have that prokaryotes do not?

Membrane-enclosed organelles

Eukaryotes and prokaryotes share 4 key traits. Name them.

Cytosol, chromosomes, ribosomes, cytoplasm

What does organelle mean?

Little organ

The membrane that surrounds each organelle in a eukaryotic cell is made of ______ and ______.

lipids, proteins

What is cellular metabolism?

Cell chemical activities

What organelles do plant cells NOT contain?

Lysosomes, centrosomes

Plant cells only have flagella on their ______ cells.

sperm

Plant cell walls are comprised of ________.

cellulose

What are the cytoplasmic channels that connect plant cells called?

Plasmodesmata

What do chloroplasts aid in?

Photosynthesis

What does turgid mean?

Rigid, structurally sound

Plant cells have massive ___________ that stores water and chemicals, as well as keeps the cell turgid.

central vacuoles

The nucleus is the cell’s __________ and contains DNA.

control center

What are chromatids?

Identical halves of a replicated chromosome

The membrane that the nucleus is enclosed in is known as the ____________.

nuclear envelope

rRNA (ribosomal RNA) is made in the ________.

nucleolus

mRNA (messenger RNA) directs __________.

protein synthesis

Ribosomes carry out commands from the nucleus in order to ___________.

make proteins

Ribosomes are made up of ___________.

proteins and rRNA

Ribosomes can be found in 3 different places within the cell. Name them.

Cytosol, nuclear envelope, ER

Cells that require lots of energy (such as muscle cells) require lots of protein. Subsequently, they have…

lots of ribosomes

What is the endomembrane system?

System found in eukaryotic cells that processes and transports lipids and proteins

What is the largest component of the endomembrane system?

Endoplasmic reticulum

The endoplasmic reticulum (ER) has two major parts: _____ and ______.

rough, smooth

The smooth ER synthesizes ________ such as oils, steroids, and phospholipids.

lipids

What kinds of cells are abundant in the smooth ER?

Sex organ, liver

The smooth ER stores ________ ions, which are responsible for __________.

calcium, muscle contraction

Many cells secrete ______ that attach to the rough ER, (ex. insulin, pancreas) making it look bumpy or “rough”.

proteins

What are the four steps in synthesis modification and secretory protein packaging?

1. Polypeptides synthesized by ribosomes and folded into 3D shapes

2. Short sugar chains attach, making glycoprotein

3. Glycoprotein exported via transport vesicle from the ER

4. Molecule is carried to the Golgi apparatus

Who discovered the Golgi apparatus in 1898?

Camillo Golgi

The number of Golgi stacks correlates with…

how active the cell is in secreting proteins

What are the four steps of molecular processing within the Golgi apparatus?

1. Cis face receives transport vesicles from ER

2. Vesicle fuses with Golgi sac

3. ER products are modified through each Golgi stack

4. Trans face ships the modified products out in vesicles

Lysosomes are…

sacs of digestive enzymes

What does “lysosome” mean?

Breakdown body

True or False: Our white blood cells destroy bacteria using lysosomes.

True

Lysosomes are directly involved in digestion in protists. How so?

Lysosomes fuse with food particles and break them down in the vacuole

Lysosomes are recycling centers. They do this by…

absorbing damaged organelles into vesicles, breaking them down, and then releasing the individual parts to remake new organelles

In protists, vacuoles…

store food and control cell water volume

In plants and fungi, vacuoles…

aid in digestion

In plant seeds, vacuoles…

store cells that contain proteins (ex. pigment in flower petals)

Plants have a large central vacuole that keeps the cells turgid by __________.

absorbing water

What are some additional functions of central vacuoles in plant cells?

Stockpiling chemicals and safely storing toxic waste

Peroxisomes are…

metabolic compartments

Peroxisomes have 2 functions. Name them.

Breaking down fatty acids, detoxifying harmful compounds

What is the MAIN function of the mitochondria in eukaryotes?

Cellular respiration

Cellular respiration makes use of oxygen and carbon dioxide to…

transform chemical energy from food into ATP

What is the mitochondrial matrix?

Storage for mitochondrial DNA, ribosomes, and enzymes that catalyze cellular respiration

The inner membrane of the mitochondria is folded to…

increase surface area

Chloroplasts are…

organelles responsible for photosynthesis in plants and algae

What are stroma?

Compartment inside inner membrane of chloroplasts that hold DNA, enzymes, and ribosomes

What are thylakoids?

Network of interconnected sacs within the stroma in stacks called grana

What are grana?

Chlorophyll-embedded solar power packs in the thylakoid membrane

What is endosymbiant theory?

Mitochondria and chloroplasts were once prokaryotes that formed a symbiotic relationship with larger cells

Mitochondria and chloroplasts have their own ______ and _________.

DNA, ribosomes

What is the cytoskeleton?

Network of fibers that provides cell structural support; aids in movement

What are the three main fibers of the cytoskeleton?

Microtubules, intermediate filaments, microfilaments

Microtubules are straight, hollow tubes made of globular _______ proteins.

tubulin

Microtubule tubulin proteins contain two subunits, called _______ and _______.

a-tubulin, b-tubulin

Microtubules grow from the _______ in animal cells.

centrosome

What is one of the main functions of microtubules aside from aiding in support and cell movement?

Guide chromosomes during division

What are intermediate filaments?

Fibrous proteins coiled into cables

Aside from cell shape support, what do intermediate filaments do?

Anchor organelles into place

Microfilaments are also known as __________ filaments.

actin

When microfilaments (actin filaments) interact with the motor protein myosin, what happens?

Muscle contraction

What is the extracellular matrix?

Layer that holds cell tissue together and supports the plasma membrane (remember: animal cells only!)

What is the extracellular matrix MOSTLY composed of?

Glycoproteins like collagen

The extracellular matrix can attach to the cell membrane via proteins called ________.

integrins

Tight cell junctions…

prevent fluid leakage

Adherens cell junctions…

help cells stick together

Anchoring or desmosome cell junctions…

rivet or weld cells into strong sheets