Cell Structure and Function

What happens to the surface area to volume ratio as cells decrease in size?

It increases

What does the Cell Theory State?

1. All living organisms are composed of one or more cells

2. Cell are the smallest units of life

3. New cells come only from pre-existing cells by cell division

List 3 differences between Eukaryotic cells and Prokaryotic cells.

1. Eukaryotic cells have a nucleus and prokaryotic cells do not.

2. Eukaryotic cells have membrane-bound organelles and prokaryotic cells do not.

3. Eukaryotic cells are generally larger and more complex than prokaryotic cells.

What is the name for a sphere shaped prokaryotic cell?

Cocci

What is the name for a rod shaped prokaryotic cell?

Bacilli

What is the name for a spiral shaped prokaryotic cell?

Spirilli

What is the name of the cellular membrane that separates the inside of the cell from the outside of the cell?

The plasma membrane

In a prokaryotic cell, what is the name of the region enclosed by the plasma membrane?

The cytoplasm

In a prokaryotic cell, what is the name of the region where the DNA is located?

The nucleoid

In a cell, what is the name of the structures that synthesize proteins?

Ribosomes

What is the fluid portion of the cytoplasm called?

The cytosol

In a prokaryotic cell, what is the name of the rigid structure that surrounds the plasma membrane and is responsible for maintaining cell shape and protecting the cell?

The cell wall

In a prokaryotic cell, these short projections from the cell surface can be used for attachment or movement?

Pili

In a prokaryotic cell, these long projections from the cell surface are used for motility?

Flagella

What is the name of the viscous substance secreted by some bacteria that helps to prevent the cell from drying out?

The glycocalyx

What is the name for a thick glycocalyx? It can be important for attachment or for evading an immune system.

A capsule

In a eukaryotic cell, that is the name of the region contained within the plasma membrane but outside of all the membrane-bound organelles?

The cytoplasm

Where is the main genome (DNA) located in a eukaryotic cell?

The nucleus.

What two processes, that we discussed, occur in the nucleus?

DNA Replication and Transcription

What is the name of the barrier that surrounds the nucleus?

The nuclear envelope

Describe the nuclear envelope.

The nuclear envelope consists of two membranes an outer and inner nuclear membrane. There are also passageways in the nuclear envelope called nuclear pores that allow for the regulated movement of things into and out of the nucleus.

What is the name of the passageways in the nuclear envelope that regulate the movement of things into and out of the nucleus?

Nuclear Pores

What is the name of the structure in the nucleus where rRNA synthesis and ribosome assembly occurs?

The nucleolus

What is the difference between the rough ER and the smooth ER?

The rough ER has ribosomes bound to its surface and the smooth ER lacks ribosomes?

What are two important roles preformed by the ER?

Protein and lipid synthesis.

What part of the ER synthesizes proteins?

The rough ER

What types of proteins are made by the rough ER?

1. Secreted proteins

2. Transmembrane proteins, including ones in the plasma membrane.

3. ER proteins

4. Golgi Apparatus proteins

5. Lysosome proteins

6. Vacuole proteins

What are some of the functions of the smooth ER?

1. Lipid synthesis (including phospholipids)

2. Storage of calcium ions

3. Detoxification of drugs and poisons

What membran-bound organelle receives proteins from the ER, modifies them, and packages them to be sent to various cellular locations?

The Golgi Apparatus

What part of the golgi is closest to the ER?

the cis golgi

What part of the golgi is closest to the plasma membrane?

the trans golgi

What part of the golgi is between the cis golgi and trans golgi?

the medial golgi

What is the name of the pathway used by the cell to place proteins outside of the cell that involves the ER and golgi?

Secretory Pathway

Write the order of the secretory pathway.

ER-->Vesicle-->Golgi--> Vesicle-->Plasma membrane -->Outside of the cell

What membrane bound organelle is used to digest substances take up from the outside of the cell and also to break down cellular molecules to recycle their building blocks?

Lysosomes

What types of enzymes do lysosomes contain?

Hydrolases

What is the pH of a lysosome compared to the pH of the cytoplasm?

The pH in a lysosome is around 4.8 and pH of the cytoplasm is around 7.

What membrane-bound organelle is used to detoxify alcohol and other harmful compounds and also to break down fatty acids? They also produce hydrogen peroxide.

Peroxisomes

What is the name of the organelle, which is not membrane bound, that is used to break down proteins?

Proteosome

What type of vacuole found in many fresh water protists is used to expel excess water from the cell?

Contractile Vacuole

What large vacuole is found in plant cells?

The central vacuole

What are 3 functions of central vacuoles?

1. Storage - they store large amounts of water

2. They are important for plant stucture

3. They are involved in cell growth in plants

What type of vacuoles can be found in macrophages and neutrophils in your body?

Phagocytic vacuoles

What to macrophages and neutrophils use phagocytic vacuoles for?

They use them to destroy bacteria.

What type of vacuole is found in protists and used to digest food that this take up from the outside?

Phagocytic vacuoles (Food vacuoles)

What membrane bound organelles (other than the nucleus) contain DNA?

Mitochondria and Chloroplasts

What membrane bound organelles originated from endosymbiosis involving bacteria?

Mitochondria and Chloroplasts

What is the name of the theory that describes the origins of mitochondria and chloroplasts?

The endosymbiosis theory

What is the primary role of mitochondria?

To make ATP.

How many membranes do mitochondria have?

2. The outer mitochondrial membrane and the inner mitochondrial membrane.

In mitochondria, what is the intermembrane space?

It is the region between the inner and outer membrane.

What is the mitochondrial matrix?

It is the region surrounded by the inner membrane.

What is name given to the folds of the inner mitochondrial membrane?

Cristae

Where are the DNA and ribosomes located in the mitochondria?

The mitochondrial matrix.

What parts of aerobic respiration occur in the mitochondria? Also explain where they occur in the mitochondria.

Pyruvate Oxidation, Krebs Cycle, and Oxidative Phosphorylation occur in the mitochondria. Pyruvate Oxidation and the Krebs Cycle occur in the mitochondrial matrix. Oxidative Phosphorylation occurs in the inner mitochondrial membrane.

How many membranes do chloroplasts have? Also name them.

3. The outer membrane, the inner membrane, and the thylakoid membrane.

In a chloroplast, what is the name of the disc like structures formed by the thylakoid membrane?

Thylakoids

What is the thylakoid lumen?

It is the region enclosed by the thylakoid membrane. So, the inside of a thylakoid.

What is the stroma in a chloroplast?

It is the region between the inner membrane and the thylakoid membrane.

Where are the DNA and ribosomes located in a chloroplasts?

In the stroma

What is the function of chloroplasts?

They perform photosynthesis

What stage of photosynthesis occurs at the thylakoid membrane?

The light reactions

What stage of photosynthesis occurs in the stroma?

The Calvin Cycle

List 3 functions for the cytoskeleton.

1. Maintains cell shape and support

2. Provides for various types of cell movement

3. Some of its fibers act as tracks or supports for "motor proteins", which help the cell move or move things within the cell

What are the 3 kinds of cytoskeletal filaments?

Microtubules

Intermediate Filaments

Microfilaments (also called actin filaments)

What cytoskeletal filament is made from tubulin?

Microtubules

What cytoskeletal filament is made from actin?

Microfilaments (also called actin filaments)

What are two examples of microtubule organizing centers?

Centrosomes and Basal Bodies

What is a microtubule organizing center?

It is an area of the cell from which micortubules grow. Exmaples: Centrosomes and Basal Bodies

What cytokeletal filament is found in cilia and flagella?

Microtubules

What cytokeletal filament is found in pseudopodia, microvilli, and llamelopodia?

Actin Filaments

What cytoskeletal filament is the nuclear lamina made of?

Intermediate Filaments

What cytokeletal filament is involved in separating the chromosomes during cell division?

Microtubules

List 3 differences between cilia and flagella.

1. Flagella are longer than cilia.

2. A cell usually only has one or two flagella, but cilia are usually present in greater numbers.

3. They have different beating patters.

What do cilia and flagella have in common?

The have the same internal structure, both contain a 9+2 array of microtubules.

What types of organelles are used for movement by eukaryotic cells?

Flagella and Cilia

What cytoskeletal filament is involved in muscle contraction?

Actin Filaments

What cytoskeletal filament is involved in cytokinesis in animal cells?

Actin Filaments

What type of proteins use energy derived from ATP to walk along cytoskeletal filaments?

Motor Proteins

Many types of cell movement involve the interaction of motor proteins with what?

A cytoskeletal filament

What is a sorting signal?

A sorting signal is a short sequence of amino acids within a protein that directs the protein to its correct location.

What is the example of a sorting signal that we learned in class?

The ER signal sequence

What type of sorting occurs after a protein has been produced?

Post-Translational Sorting

What type of sorting occurs while the protein is being produced?

Cotranslational Sorting

What type of sorting do proteins directed to the ER undergo?

Cotranslational

What types of proteins undergo post-translational sorting?

Proteins located in the:

nucleus

mitochondria

chloroplasts

peroxisomes

Other than ER proteins, what other types of proteins are cotranslationally sorted to the ER?

Golgi proteins

Lysosome proteins

Vacuole proteins

Plasma membrane proteins

Secreted proteins.

How do proteins sorted to the ER get to the golgi apparatus?

through a vesicle

How do proteins get from the golgi apparatus to their final destination?

through a vesicle

Place the following steps of cotranslational sorting to the ER in the correct order:

1. SRP binds to the SRP Receptor in the ER memrbane

2. SRP is released, translation resumes, and the protein is synthesized into the ER lumen

3. The ER signal sequence emerges from the ribosome

4. SRP binds to the ER signal sequence and pauses translation

1. The ER signal sequence emerges from the ribosome

2. SRP binds to the ER signal sequence and pauses translation

3. SRP binds to the SRP receptor in the ER membrane

4. SRP is released, translation resumes, and the protein is synthesized into the ER lumen

Why is cell signaling important?

1. It allows cells to respond to their environment.

2. It allows cells to communicate with each other.

What are the 3 parts to a signaling pathway?

1. A receptor

2. A signal transduction pathway

3. Effector proteins

What part of a signaling pathway detects the signal?

The receptor.

What part of a signaling pathway relays the signal from the receptor to the effector proteins?

The signal transduction pathway.

What part of a signaling pathway carries out the cell's response?

The effector proteins.

What allows a cell to respond to a specific signal?

A receptor.

What are the 5 types of cell to cell communication?

1. Contact-dependent signaling

2. Paracrine signaling

3. Synaptic signaling

4. Endocrine signaling

5. Autocrine signaling

In what type of cell to cell communication is the ligand and receptor tethered to their respective cells? This form involves the cells touching.

Contact-dependent signaling

What type of cell to cell communication is a local form of signaling where one cell releases the ligand which will then bind to a receptor on a neighboring cell?

Paracrine signaling

What form of cell to cell communication is a specialized form of paracrine signaling used by neurons, where the ligand is a neurotransmitter?

Synaptic signaling