IB Biology Chapter 1 Test
Terms in this set (73)
-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?
Actual size of a cell formula
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)
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
Producing different cells for different purposes
Stage of embryo development (150-200 cells) where all cells are the same
Embryonic stem cells which have the ability to turn into many cell types
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
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
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
-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
Higher concentration of solutes outside of the cell (more water inside cell than outside)
Higher concentration of solutes inside the cell (more water outside cell than inside)
Same solute concentration inside and outside of the cell
What is active transport?
-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)
-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.
-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
-"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.
-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).
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
Structures within cells that convert the energy from food into a form that cells can use.
Any organism whose cells have a cell nucleus and other organelles enclosed within membranes
Characteristics of eukaryotes in an animal cell
-Cell wall absent
-Cholesterol in membrane
Characteristics of eukaryotes in a plant cell
-Cell wall present
-No cholesterol in membrane
-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
-"Not membrane bound"
~Flagellum (used for mobility)
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
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
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).
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
-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)
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)
Molecule that helps speed up chemical reactions
# 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!!)
Restricted to 1 tissue/organ and cells are non-cancerous
Cancerous cells migrate and new tumors form in other tissues (metastasis)
-Mutate DNA and one factor that causes cancer
-Also called carcinogens
DNA molecule w/ part of all the genetic material of an organism
The daughter strands of a replicated chromosome.
The material a chromosome is made of.
-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)
-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.