Biology- endosymbiotic theory, cytoskeleton, matrix & cell junctions

prokaryotes

Chloroplasts were once small ________________ that began living within larger cells

aerobic

The world became more ______________ from oxygen-generating photosynthesis.

the host could provide energy from oxygen and the endosymbiont could provide food for the host

How did organisms live in other organisms?

Cytoskeleton

Network of protein fibers that support the structure of the cell and extend throughout the cytoplasm

support and motility

The cytoskeleton gives structural ______________ and _____________.

Microfilaments/actin

The thinnest cytoskeletal fibers; they are made of globular proteins arranged in a twisted double chain

around the periphery (inside the cell membrane)

Where is the actin located within the cell?

It interacts with myosin to cause muscle movement

What does microfilaments/actin do in a cell?

Intermediate Filaments

Middle size cytoskeletal fibers made of various fibrous proteins that supercoil into thick cables

they reinforce cell shape, and anchor organelles like the nucleus

What is the role of intermediate filaments in the cell?

keratin

The outer layer of your skin is full of dead cells with intermediate fibers made of ____________

Microtubules

The thickest cytoskeletal fibers made of globular proteins called tubulins; they are straight, hollow tubes

they are the main component of cilia and flagella, they shape and support the cell, and they act as a track for chromosomes to move across when cells divide

What is the function of microtubules in cells?

Cilia and Flagella

Composed of microtubules wrapped with extensions of the plasma membrane; arranged in a 9+2 pattern with 9 doublets and 2 singlets of microtubules

move

When the microtubules bend, the cilia and flagella __________.

PCD (Primary Cilia Dyskinesia)

Disorder when microtubules in a cell lack dynein arms which means the cilia cannot move

Extracellular Matrix

the "stuff" attached to the outside of the plasma membrane. it is mostly glycoproteins like collagen

Collagen

40% of the protein in your body is _____________

Integrins

Integral proteins that attach the glycoproteins and other extracellular fibers to the cell membrane

CDs (clusters of differentiation)

how your body knows its you and not something else

Cell Junctions

how cells communicate with the cells next to them

Tight junctions

Seals cells together to prevent anything from leaking into or out of a layer of cells

anchoring junctions

cells get fastened together into strong sheets. intermediate filaments made of keratin anchor junctions in the cytoplasm; for areas that are in a lot of stress

Gap junctions

Communicating junctions; small channels between cells that allow messages through

Plasmodesma

Similar to gap junctions in animal cells, a continuation of cytoplasm for communication between plant cells

Cell membrane

Structure composed of phospholipids that protects the contents of the cell and contains proteins that have different jobs based on their structure

phospholipid

The cell membrane is made of a ____________________ bilayer

hydrophilic heads pointing outward and hydrophobic tails facing inward

What is a lipid bilayer made up of?

amphipathic

when a molecule has hydrophilic and hydrophobic parts

flexible

Unsaturated fatty acid makes the structure more ________________ and more fluid

Leaflet

Each side of the lipid bilayer is called this

sticky

Cholesterol is __________.

It helps to solidify the cell membrane, so that the cell membrane does a better job of choosing what goes and goes out.

What is the main role of cholesterol?

The membrane could break apart and it wouldn't hold the shape of the cell, forming gaps, and anything would be able to go into and out of the cell.

Why would you not want the plasma membrane to be too fluid?

Saturated vs. unsaturated fatty acid tails

What keeps the cell membrane fluid?

by having cholesterol- it keeps the membrane more stable and rigid

How do you prevent a cell membrane from becoming too fluid?

bad

Too much or not enough cholesterol is a ________ thing

Homeostasis

Keeping a stable environment inside of the cells based on what's going on outside of the cells

Plasma membrane

Cells need the ___________ _____________ to keep a stable environment inside the cells, maintaining homeostasis