Biology Chapter 6: A Tour of the Cell

What are the two different types of cells?

eukaryotic (more complex, with nucleus and membrane bound organelles), prokaryotic (simpler, smaller and without nucleus)

Plasma membrane

-All cells contain it

-is a selective barrier. in small things, non polar, not charged

-cell increases in size, volume grows more proportionately than are (plasma) hence why cells split before getting too large

Why do organisms generally have many cells, not smaller cells?

-cells increase, volume grows way more than area, so cell splits before it gets too large

What is the fluid inside a cell?

Cytosol, cytoplasm

What are chromosomes?

Carry genes in form of DNA

What are ribosomes

organelle that makes proteins

What are some differences between prokaryotic and eukaryotic cells?

1) location of DNA - prokaryotes dont have

2) other membrane bound organelles - prokaryotes dont

3) complexity - eukaryotes more complex

4) size - eukaryotes tend to be larger

5) Presence of flagella/fimbriae - prokaryotes have, eukaryotes dont

Prokaryotes have:

fimbrae - movement on the surface of some

nucleoid - region where cell's DNA is, but not enclosed

ribosomes - make proteins

plasma membrane

cell wall/capsule

flagella - for movement

What is the nucleoid?

In prokaryotes, it is where the cell's DNA is stored, but it is NOT an enclosed organelle.

What are some differences bw an animal and a plant cell?

Animal - has centriole, lysosomes, ECM

Plant - has central vacuole, chloroplasts, amyloplast (starch grain), cell wall, chlorophyll, photosynthesizes

Cell Membrane is also known as

Plasma membrane

What are membranes made of usually?

A double layer of phospholipids, as well as other lipids (like cholesterol) and proteins

What is the primary purpose of a cell membrane?

To control movement in and out of the cell, define cell from outside space

The nucleus

-part of the endomembrane system

-contains most of genes

-has double membrane itself

-has pores that allow mRNA in and out of the nucleus

-pore complex lines each pore and regulates entrance and exit of proteins

Structure of the nucleus

DNA is loacted in

chromosomes, made up of a material called chromatin (proteins and DNA)

what is the nucleolus?

Nucleolus produces ribosomes

Ribosomes

-make proteins

-both in prokaryotic and eukaryotic

Ribosome

Notice that there is a space b/w small subunit and large subunit. This is where the ribosome pieces together a protein.

Transport vesicles

Transport vesicles budd off ER and other endomembrane organelles. It fuses with their membrane.

-walks along tracks of microtubules (think kinesin feet)

What is the golgi Apparatus

A stack of flattened sacks

What happens in the golgi?

-packing, sorting, modification of phospholipids, proteins

-many polsyaccharides are made here

-storage of lysosome enzymes

Lysosomes

membranous sac of digestive enzymes

-mergers with food vacuoles at eats them!

Vacuoles

For:

-water balance,

-waste storage

-food storage

What is the central vacuole in a plant cell?

In plants, holds food, water, waste, starch

-also helps to hold up the cell (it's HUGE)

solution inside vacuole is sap and not cytosol

What are the organelles in the endomembrane system? What organelles are membrane bound?

plasma

nucleus

endoplasmic reticulum

Central Vacuole

Golgi

Vesicles

What are the two types of ER?

-made of rough ER - protein synthesis and storage, smooth er - lipid synthesis

What do rough ER do?

-Rough ER has ribosomes attached

-these ribosomes are where protein syntehsis takes place

-transport vesicles bud from rough ER

What do smooth ER do?

-outer surface lacks ribosomes - smooth

-synthesices lipids

structure of ER

What are chloroplasts

only in plant cells, source of photosynthesis

What is the structure of a chlorplast?

outside is outer membrane

inner membrane

In the stroma (flui), there are stacks of thylakoids

Structure of a chlorplast

Mitochondria's function

site of metabolic activity, creates ATP

extracts energy from food

Structure of mitochondria

outside layer smooth

inbetween is intermembrane space

inside membrane layer folded into layers of cristae

Structure of a mitochondria

cytoskeleton

network of fibers extending through cytoplasm for support and movement

Motor proteins interact with cytoskeleton for cell motility - flagellum and cilia

What are the two types of cytoskeleton fibers we learned about?

1) microtubules

3)microfilaments

Microtubules

Main functions: cell motility, maintenance of cell shape, chorosome movements in cell division (division spindle forms here), organelle movements

Structure-hollow tubes made from proteins

Cilia and flagella are made out of which cytoskeleton type?

Microtubules

What is the difference between cilia and flagella

Cilia - usualy has many, but shorter and they beat like oars. Can also be used for senseing what's going on ouside cell

Flagella, one or a few, longer, undulating motion that generates movement

What is the structure of microtubules?

They grow by adding subunits (protwins). they are HOLLOW

they are organized in centrosomes

What are centrioles?

used for cell division in animal cells, grows out of centrosomes. Division spindle grows out of the centrioles.

Which is the thickest cytoskeleton type?

microtubules

Microfilaments

Main functions: maintenance of cell shape, changes in cell shape, muscle contraction, cell motility, cell division (cleavage formation), muscle contraction, cytoplasmic streaming

Structure-globular protein actin.

Plant cell walls

-made from microfibrils of cellulose

-primary cell wall (young plant cell, thin and flexible)

-middle lamella (b/w primary walls of adjacent cells, have pectins)

-secondary cell - matures and stops growing, plant cell strengthens its walls