Study Guide b pt 1 Flashcards
What are the characteristics of eukaryotic cells?
- make up multicellular organisms such as plants and animals
- complex cells with a nucleus and membrane bound organelles
What are the characteristics of Prokaryotic cells?
- single celled organisms
- simple structures and do not have a nucleus or any membrane-bound organelles
What do eukaryotic and prokaryotic cells have in common?
They both have a cell membrane, contain ribosomes, and they both have DNA and cytoplasm.
What is cytoplasm?
A jellylike substance that contains dissolved molecular building blocks and in some types of cells, organelles.
Where do you find organelles?
Cytoplasm
What statements summarize scientists’ concept of cells?
Cell Theory: all living things are composed of cells, cells are the basic units of structure and function in living things, and new cell are produced from existing cells.
Which type of cells have no nucleus
Prokaryotic cells
What are the functions of a cytoskeleton?
supports and shapes the cell, positions and transports organelles, provides strength, assists in cell division, and aids cell movement.
How is a cytoskeleton like your muscles?
It provides structure and protects vital organs contained with it. Also shapes the cell.
Function of the nucleus:
stores most of the genetic information of a cell (DNA); and controls the cell’s activities and functions
Function of Endoplasmic Reticulum:
helps in the production of proteins and lipids
Function of ribosomes:
link amino acids together to form proteins
Function of golgi apparatus:
processes, sorts, and delivers proteins
Function of vesicles:
carries certain molecules from place to place within a cell (water, proteins, and enzymes)
Functions of mitochondrion:
supply energy to the cell by converting molecules from food (glucose) into usable energy
Function of vacuole:
stores materials needed in a cell; may help provide support to plant cells
Function of lysosome:
organelles that contain enzymes that break down damaged and worn-out cell parts; defends a cell from invaders.
Function of centriole:
help form cilia and flagella, structures that help cells to over or to move liquids past a cell
What role do cell walls play in a plant?
Cell walls protect, support, and shape the plant cell. They are strong and rigid and adhere to each other, which helps to support entire plant.
What is the difference between a cell wall and a cell membrane?
The cell wall is the outside lining of the cell that helps hold the cell together. the cell membrane is inside the cell and is semi-permeable so it allows various substances to go in and out of the cell. all cells have a cell membrane, but only certain cells have a cell wall
Why are chloroplasts so important?
Chloroplasts are the powerhouse of the plant cell. They convert solar energy to energy-rich molecules that cells can use. (photosynthesis) also convert solar energy, carbon dioxide, and oxygen to sugar.
Which cell part is a maze of folded membranes where proteins an lipids are produced?
The Endoplasmic Reticulum
Which cell part converts food into energy that is usable by a cell?
Mitochondria
What are the three major parts of the phospholipid?
Hydrophilic Head (Phosphate Head), Glycerol, and Hydrophobic Tails (Fatty Acid Tails)
Which part of a phospholipid is charged, or polar?
The charged phosphate head and glycerol
Which part of a phospholipid is nonpolar?
Fatty Acid Tails
What type of molecules interact with water, polar or nonpolar?
polar molecules
Where does a cell membrane come into contact with water?
outside of the cell because of the extracellular fluid and inside the cell because of the cytoplasm
Why do the phospholipids surrounding the cell form a bilayer?
the polar heads interact with the watery environments both inside and outside the cell. The non-polar tails interact with each other inside the membrane.
Function of Cholesterol:
Strengthen cell membrane
Function of Proteins:
helps materials cross the membrane, part of cytoskeleton
Function of carbohydrates:
help identify cell types and provides cells with energy
In what way is a membrane fluid?
the phospholipids in each layer can move from side to side and slide past each other
What does a receptor do?
detects a signal molecule and carries out an action in response
What is a ligand?
A molecule that acts as a signal when it binds to a receptor.
A ligand that can cross the cell membrane can bind to what kind of receptor?
intracellular
A ligand that cannot cross the cell membrane can send a message to a cell by binding to what receptor, then does what?
membrane receptor; changes shape
What is the fluid mosaic model?
describes the arrangement of molecules that make up the cell membrane. (gives flexibility and emphasizes both he fluidity of the membrane and the variety of molecules that make up the membrane)
The cell membrane allows some, but not all moleucles to cross. What term describes this property?
Selective Permeability
What is a concentration gradient?
the difference in the concentration of a substance form one location to another.
What does it mean for a molecule to diffuse down a concentration gradient?
the molecule diffuses from an area of higher concentration into an area of lower concentration
Passive transport requires no _____ from cell.
energy
What are two examples of passive transport:
diffusion and osmosis
What is osmosis?
the diffusion of water
What is diffusion?
the movement of molecules down a concentration gradient
Where does the energy come from in diffusion?
natural motion of particles
the higher the concentration of dissolved particles in a solution, the ______ the concentration of water molecules in that solution.
lower
Which solution has the highest concentration of particles?
hypertonic
which solution has the highest concentration of water molecules?
hypotonic
How does facilitated diffusion differ from simple diffusion?
facilitated diffusion occurs through selective transport proteins, not simply across the membrane.
In facilitated diffusion, do molecules move down a concentration gradient or against a concentration gradient?
down a concentration gradient
The difference in the concentration of a substance from one location to another is a _________.
concentration gradient
People with excess energy are described as hyper. How does this relate to the meaning of hypertonic?
A hypertonic solution has a higher level of solutes than the solution it is being compared to.
The word facilitate means “to make easier.” How does this meaning apply to facilitated diffusion?
the transport protein makes it easier for a molecule that cannot directly cross the cell membrane to enter or exit a cell.
How is active transport different than simple diffusion and facilitated diffusion?
Active transport is the movement of molecules against a concentration gradient whereas any type of diffusion is the movement of molecules down a concentration gradient.
How is active transport similar to facilitated diffusion?
they both involve the movement of molecules through selective membrane proteins.
List two characteristics that almost all transport proteins share.
Spans the membrane and changes the shape when they bind to a target molecule(s).
List the key distinguishing feature of active transport proteins.
Uses energy in order to move a substance against its concentration gradient
Most active transport proteins use energy from the breakdown of ______.
ATP
A cell may transport a substance in vesicles if the substance is…
too large to cross the membrane.
During endocytosis, the vesicle membrane fuses with a lysosome, and the membrane and its contents are broken down by __________.
lysosomal enzymes
Characteristics of endocytosis
Takes substances in the cell, uses energy, and moves substances in vesicles
Characteristics of exocytosis
releases substances outside a cell, uses energy, and moves substances into vesicles
What term means “cell eating” and describes a type of endocytosis?
Phagocytosis
The prefix exo- means “out of” and the prefix endo- means “taking in.” How do these meanings relate to the meaning of exocytosis and endocytosis?
Exocytosis is a process that releases substances outside a cell. Endocytosis is a process that takes substances into a cell.
What process drives molecules across a membrane against a concentration gradient?
Active Transport
Function of flagella:
to help move the bacteria
function of nucleoid region:
essential for controlling the activity of the cell and reproduction, it is the non-centralized region of the cell where DNA can be found, and DNA is shaped like a double helix, but the region itself is undefined
Function of pilli:
used by bacteria to communicate and exchange genes and used to surface and provide a slow form of movement
What are chromosomes?
the condensed version of your entire genetic makeup by chromatic
What is chromatin?
the form of DNA when wound together and bound by histones
What are the types of vesicles?
lysosomes and vacuoles
What are factors that can affect the rate of diffusion?
particle speed and size, temperature, solvent/substrate
What is a isotonic solution?
if water diffuses in and out of the cell at same rate, then it is isotonic
what are aquaporins?
are used by cells to rapidly transport water molecules across the cell membrane
