Biology Unit 2 Vocab

Cell

the basic structural and functional units of every organism

All Cells …

1. are bound by a plasma membrane

2. contain cytosol

3. contain chromosomes

4. contain ribosomes

Plasma/cell Membrane

a thin barrier that surrounds every living cell and separates its inside from the outside world

Prokaryotes

no nucleus or membrane-bound organelles

Eukaryotes

Nucleus + membrane bound organelles

Ribosome

synthesize proteins

translate messages found on mRNA into the primary structure of polypeptides

Chromosome

DNA itself gets coiled and wrapped around proteins to form the chromosome.

Nucleoid

membrane-free region inside a prokaryotic cell that holds all or most of the genetic material

Nucleus

stores and protects DNA in eukaryotic cells

Organelle

membrane-bound structures in eukaryotes

Endomembrane System

a network of membranes and organelles in eukaryotic cells that work together to modify, package, and transport polysaccharides lipids and proteins

Vesicle

membrane-bound bubble inside a cell that moves proteins, nutrients, or waste from one part of the cell to another

mitochondria

• produces energy for the cell called ATP

• Site of cellular respiration

• Double Membrane - outer membrane is smooth, inner membrane is highly convoluted (many folds called cristae)

Energy Organelles

covert energy to forms that cells can use for work

Types of Energy Organelles:

1. Mitochondria

2. Chloroplasts

Endomembrane Organelles

1. Nuclear envelope

2. Endoplasmic reticulum

3. Golgi complex

4. Lysosmes

5. vesicles/vacuoles

6. Plasma membrane

Cytosol

water-based fluid inside a cell where the organelles float

Compartmentalization

Eukaryotic membranes and membrane-bound organelles allow diff. metabolic processes and enzymatic reactions occur in different locations

effects of compartmentalization:

• Increases surface area of reactions to occur

• Prevents intefering reactions from occuring in the same location

Chloroplast

• site of photosynthesis

• contains the green pigment chlorophyll

Nuclear Envelope outer trait

• double membrane

• has pores (to regulate entry and exit of materials fro mthe cell

• Continuous with the ER membrane

Nucleolus (what is it, what happens there?)

• Dense region of the nucleus where ribosomal rRNA is synthesized

• In the nucleolus, rRNA combines with proteins to form large and small subunits of ribosomes

How are ribosomes formed?

• In the nucleolus, rRNA combines with proteins to form large and small subunits of ribosomes

• subunits of ribosomes exit via nuclear pores and assemble into ribosomes

Endoplasmic Reticulum

• A network of membranous sacs (cisternae) and tubules

• helps cells maintain shape

• intracellular transport

• produces, folds, and modifies biological molecules, then ships them inside tiny vesicles to where they are needed

Types of ER

Rough ER:

• contains ribosomes bound to the ER membrane

• makes + transports proteins

Smooth ER:

• Contains no ribosomes

• makes lipids and detoxifies the cell

Where is the Ribosome found?

1. Cytosol

2. Bound to the ER or nuclear envelope

Cytosol

Proteins produced her generally function only within the cytosol (i.e. enzymes)

known as “free ribosomes”

Ribosomes bound to ER or nuclear envelope can do what?

proteins produced here can leave the cell via transport vesicles

Golgi Complex

• receives transport vesicles with materials from the ER

• modifies and sorts the materials

• adds molecular tags

• packages materials into new transport vesicles that exit the membrane.

Cisternae

Membranous sacs found in the ER and golgi complex

Directionality of Golgi complex

Cis face: receives vesicles from the ER

Trans face: sends vesicles back out into the cytosol to other locations or to the plasma membrane

Lyosomes

• membranous sac with hydrolyte enzymes in animal cells

• created by cisternae

• hydrolyzes macromolecules

• Autphagy: recycle the cell’s materials and organelles that are not functioning properly

• allows the cell to renew itself

• plays a role in apoptosis (programmed cell death)

Apoptosis ( programmed cell death)

membrane becomes permeable —> releases enzymes into cytoplasm —> breaks down cellular components

Peroxisomes

• membrane bound metabolic compartment

• catalyze reactions that produce H₂O₂

• break down fatty acid molecules, creates certain phospholipids, detoxify compounds

• Enzyme in peroxisomes break H₂O₂ into water and oxygen

H₂O₂

can detoxify certain compounds and damage the cell if any escapes

Vacuoles

Vesicles that stem from the ER and golgi

seletive in transport

Difference in vacuoles in animal and plant cells

Animal Cells:

• small in size

• assist endoctysosis/exocytosis processes

• store cellular materials

Plant Cells:

• Central vacuole, large in size

• stores nutrients and water

• can function like lysosomes

Plasmodesmata

channels passing through the cell walls of plants that allow direct communication and transport between cells

Centrosomes

organelle that helps cell division and organises cytoskeleton

Flagella

helps make the cell move

central vacuole

stores water and supports the structural system of plant cells

Unique Cell Components in Plants and Animals

Plants:

• chloroplasts

• central vacuole

• cell wall

• plasmodesmata

Animas:

• lysosomes

• centrosomes

• flagella

Role of Cristae in the mitochondria

divides the mitochondria into two internal compartments and increases the surface area

Intermembrane

space between inner and outer membrane

mitochondrial matrix

• enclosed by inner membrane

• location for the krebs cycle

• contains enzymes, mitochondrial dna, and ribosomes

Mitochondria + activity?

• the number of mitochondria in a cell correlates with metabolic activity

• cells with high metabolic activity ahve more mitochondria

Inside the double membrane of chloroplast

Thylakoids and stroma

Thylakoids

• membranous sacs that can organize into stacks called grana

• light dependent reactions occur in grana

Stroma

• fluid around thylakoids

• location for calvin cycle

• contains: chloroplast DNA, ribosomes, and enzymes

Endosymbiotic Theory

• mitochondria and chloroplasts evolved from once free - living prokaryotic cells

• became endosymbiont and one functional organism

Evidence: 1. microtubules

2. microfilaments

3. intermediate filaments

Microtubules

• thickest filaments in cytoskeleton

• in animal cells they grow from the centrosome

• structural support for the movement of organelles that interact with proteins

• assist the movement of chromosomes during cell division

• cell motility (the ability of cells to move)

Microfilaments

• Thin, solid rods made of protcein actin

• maintain cell shape

• assist in muscle contraction and cell motility

• division of animal cells

Intermediate filaments

• Fibrous proteins made up of varying subunits

• permanent structural elements of cells

• maintain cell shape

• anchor nucleus and organelles

• form the nuclear lamina (lines the nuclear envelope)

centricoles

structured within a centrosome, helps with nuclear division and composed of microtubules.

tight junctions

join cells together in the formation of tissues

middle lamella

first layer of the cell wall