IB Biology Chapter 1 Test

Cell Theory

-Living organisms are composed of cells
-Cells are the smallest unit of life
-All cells come from preexisting cells

What are the functions of life?

Metabolism, growth, response (sensitivity), homeostasis, nutrition, reproduction, and excretion

What functions of life do unicellular organisms undergo?

ALL functions

Actual size of a cell formula

Actual=Image/Magnification

What does the surface area of a cell determine?

Rate of exchange of materials

What does the volume of a cell determine?

Metabolic activity (how much stuff can occur)

SA:V Ratio

Rate of exchange of materials : metabolic activity

What happens if there is not enough exchange of materials?

Not enough energy for metabolism

What happens if a cell is too big?

It must divide

Differentiation

Producing different cells for different purposes

Blastocyst

Stage of embryo development (150-200 cells) where all cells are the same

Pluripotent

Embryonic stem cells which have the ability to turn into many cell types

Multipotent

Adult stem cells that can turn into different cells of that tissue. EX: Bone marrow- variety of white blood cells, red blood cells.

Characteristics of eukaryotes

-Has nucleus
-Has organelles
-"Membrane boundness"

Functions of nucleus

-Within plant and animal cells
-Contains DNA and Chromosomes

Function of endoplasmic reticulum

-Within plant and animal cells
-Rough: ribosomes connected to cisternae that produce proteins
-Smooth: help with protein folding

Function of mitochondria

-Produces energy (ATP) to move a cell from high concentration to low concentration
-Regulates cellular metabolism
-Takes in nutrients from the cell, breaks it down, and turns it into energy (cellular respiration)

Function of golgi apparatus

-Process and bundle macromolecules like proteins and lipids as they are synthesized within the cell.

Function of chloroplasts

-In plant cells but not animal
-Site of photosynthesis

Function of lysosomes

-In both plant and animal cells
-Contains enzymes for intracellular digestion

Intracellular Digestion

Break down of substances within the cytoplasm of a cell

Function of vacuole

-In plant cells
-Enclosed compartments that are filled with both inorganic and organic molecules, along with water to support the organelle.

What creates a phospholipid bilayer?

Hydrophobic and Hydrophilic ends of the membrane structure

How does cholesterol affect the semipermeable membrane?

Makes membrane more rigid and less permeable to water-soluble molecules

What is simple diffusion?

-A passive process
-No energy
-molecules move down their concentration gradient (via membrane protein and via permeable membrane)
-Specific molecules pass through certain proteins IF open
*No large or charged molecules

What is facilitated diffusion?

-Movement of polar substances through channel protein
*excluding glucose, amino acids, and water
-Only a few molecules are assisted through the membrane

What is osmosis?

-Passive movement if water molecules
-Water is always moving in and out
-We measure net or average movement of water
-Dilutes solution with higher solute concentration

Hypertonic

Higher concentration of solutes outside of the cell (more water inside cell than outside)

Hypotonic

Higher concentration of solutes inside the cell (more water outside cell than inside)

Isotonic

Same solute concentration inside and outside of the cell

What is active transport?

-Requires energy
-In the form of ATP
-The movement of ions or molecules across a cell membrane into a region of higher concentration, assisted by enzymes and requiring energy (ATP)

Endocytosis

-Bacterium is engulfed by cell membrane. This creates a vesicle that lysosomes work to digest.
-Chamberlain def: When one cell pacman's bacterium particle to create new cell. Lysosomes break this down and digest during exocytosis. Exocytosis undoes endocytosis.

Exocytosis

-Cells carry large, bulky molecules or mass of molecules via vesicles.
-Protein production from ER is packaged into vesicles by the golgi apparatus. Vesicles fuse with membrane + proteins are released
-Also occurs with neurotransmitters in neurons
- Exocytosis undoes endocytosis

Endosymbiotic Theory

-"endo"=inside, "symbiotic"=life together
-Theory that a large prokaryote engulfed a smaller one to create mini membrane bound cells in another

Support of Endosymbiotic Theory (Characteristics of Mitochondria and Chloroplasts)

-Contain ribosomes smaller than those in eukaryotes but the same size as many bacteria
-Contains small circular DNA resembling bacteria plasmids
-Have their own envelope surrounding them AND inner membranes contain own protein which are synthesized by the organelle.
-Replicate by binary fission.

Plasmid

-Typically a small circular DNA strand in the cytoplasm of a bacterium or protozoan.
-Bacteria's version of a chromosome and often helps it mutate rapidly causing bacterial resistance.
-Bacteria can gain new plasmids or lose them.
-Copy themselves independently of the bacterial DNA (nucleoid/chromosome).

Binary Fission

Asexual reproduction by a separation of the body into two new bodies. In the process of binary fission, an organism duplicates its genetic material,(DNA), and then divides into two parts (cytokinesis), with each new organism receiving one copy of DNA.

What theory does all the things bacteria does lead to?

That organelles are modified bacteria from early in the evolution of eukaryotes

How do prokaryotes, mitochondria and chloroplasts replicate?

Via binary fission

Characteristics of Mitochondria

-Has own DNA (Mitochondrial DNA)
-Membrane bound (all organelles have membranes around them)
-Go under binary fission
-Has own ribosomes
-Within plant and animal cells
-Is an organelle within a eukaryote

Mitochondria

Structures within cells that convert the energy from food into a form that cells can use.

Eukaryote

Any organism whose cells have a cell nucleus and other organelles enclosed within membranes

Characteristics of eukaryotes in an animal cell

-Cell wall absent
-Small vacuoles
-No chloroplasts
-Cholesterol in membrane
-Centrioles present
-Store glycogen

Characteristics of eukaryotes in a plant cell

-Cell wall present
-Large vacuoles
-Chloroplasts present
-No cholesterol in membrane
-Centrioles absent
-Stores starch

Prokaryote

-A prokaryote is a unicellular organism that lacks a membrane-bound nucleus, mitochondria, or any other membrane-bound organelle.
-What creates a eukaryote

How is a eukaryote created? (theory)

When one prokaryote engulfs another prokaryotic cells which creates a nucleus, making a eukaryote

Characteristics of a prokaryote

-No nucleus or organelle
-Unicellular organism
-"Not membrane bound"
-Has:
~Cell wall
~Plasma membrane
~Cytoplasm
~Naked DNA-chromosomes
~Ribosomes
~Flagellum (used for mobility)
~Pili

How does a eukaryote divide?

Via mitosis and cytokinesis

When are cells replaced?

When they die or an organism needs to grow

Parts of the cell cycle

1. Interphase
2. Mitosis
3. Cytokinesis

Parts of Interphase

-G1 phase: Cell growth, protein synthesis
-S phase: (synthesis phase) Where DNA is replicated
-G2 phase: Making sure there's enough material to divide (mitochondria, chromosomes, etc), prepares for division.

Parts of Mitosis

-Prophase
-Metaphase
-Anaphase
-Telophase

Process of Prophase

-Chromosomes condense (super coil) and become visible
-Centrioles migrate to opposite sides-release spindle fibers.
-Nuclear envelope begins to break down.

Process of Metaphase

-Chromosomes align in the middle of the cells along microtubules. (*MIDDLE for METAPHASE)
-Spindle Fibers attach to centromeres.

Process of Anaphase

-Centromeres split and sister chromatids are pulled away from each other (*AWAY for ANAPHASE).
-Spindle fibers shorten.

Process of Telophase

-Spindle fibers break down.
-Two new nuclear envelopes are formed around each set of chromosomes (*TWO for TELOPHASE).

Cytokinesis

Division of the cytoplasm in a cell

Process of Cytokinesis in ANIMAL CELLS

-Two sides of the plasma membrane meet and two completely new cells are formed.
-New nucleus formed

Cyclins

-Control center of cell cycle
-Directs cells through the cell cycle when released
-They bind to CDKs to form enzymes that direct cells through the cell cycle and control certain events like microtubule formation and chromatid alignment.
-CDK: Cyclin Dependent Kinase (enzyme)

Cyclin Chart

Determines when cyclins are released

Types of Cyclins and purpose

-E: Preps for DNA replication in S phase
-D: Tells cell its going to go from G0- G1 phase and G1-S phase. Takes longer.
-A: Triggers DNA replication inside the nucleus in S phase
-B: Promotes assembly of the mitotic spindle and other tasks in the cytoplasm to prep for mitosis.
(*DEAB: Don't Eat All The Bacon)

Enzyme

Molecule that helps speed up chemical reactions

Mitotic Index

# of cells undergoing mitosis/total # of cells in view of microscope

How is cancer related to mitosis?

-Cell division goes unchecked and produces an excess amount of cells (Tumor!!)

Benign Tumor

Restricted to 1 tissue/organ and cells are non-cancerous

Malignant Tumor

Cancerous cells migrate and new tumors form in other tissues (metastasis)

Mutagens

-Mutate DNA and one factor that causes cancer
-Also called carcinogens

Chromosome

DNA molecule w/ part of all the genetic material of an organism

Chromatids

The daughter strands of a replicated chromosome.

Chromatin

The material a chromosome is made of.

Centromere

-What holds the two chromatids together.
-Where sister chromatids meet

How are chromosomes formed?

1. DNA spools itself around proteins called histones.
2. Histones condense to make chromatin.
3. Chromatin condenses to make chromosomes (supercoiling)
(DNA + Histones= nucleosome)
(Several nucleosome together are chromatin)

Spindle Fibers

-Form a protein structure that divides the genetic material in a cell.
-The spindle is necessary to equally divide the chromosomes in a parental cell into two daughter cells during both types of nuclear division: mitosis and meiosis.
-During mitosis, the spindle fibers are called the mitotic spindle.