The cell Flashcards
Outer boundary of the cell
Plasma membrane
Fluid within the cells
Intracellular fluid
Fluid outside and between the cells
Extracellular fluid
Makes up the lipid bilayer
Phospholipids
Heads-interact with water
Hydrophilic
Tails-do not interact with water
Hydrophobic
Makes up 20% of the membrane lipids
Stabilizes the membrane
Makes the membrane less fluid
Cholesterol
Arteries that have increased cholesterol, less fluid, and loss of flexibility
Atherosclerotic arteries
Firmly inserted into the lipid bilayer and span the entire width of the cell membrane
Integral proteins
Created by integral proteins clustering together. This allows water soluble molecules and ions to pass through the membrane
Channels
Bind to substances and move them through the membrane
Carriers
Attached to integral proteins
Help support the membrane
some are enzymes
Others change the cell’s shape during cell division and muscle cell contraction
Peripheral proteins
branches of sugar groups consisting of glycolipids and glycoproteins, gives the cell its identity
Glycocalyx
Fingerlike extensions of the plasma membrane that increases surface area for absorption, found on cells in the digestive system
Microvilli
Protein molecules in adjacent plasma membranes fuse together, form impermeable junctions that encircle the cell, and prevent molecules from passing through the extracellular space between adjacent cells.
Tight Junction
Anchoring junctions, on the cytoplasmic (inside) of the cell, adjacent cells do not touch, but are held together by thin linker proteins; found in skin
Desmosomes
Allows chemical substances to pass between adjacent cells; in embryonic cells to distribute nutrients before the circulatory system is developed and also found between heart muscle cells
Gap junctions
Transport of substances that do not use energy to cross the membrane
Passive Transport
Transport of substances that require energy to cross the membrane
Active Transport
Molecules scatter evenly throughout the environment
Diffusion
Molecules that move from areas of higher concentration to areas of lower concentration
Concentration gradient
What influences the speed of diffusion?
Size of the molecules and temperature
The unassisted diffusion of water, water follows the greater number of solutes
Osmosis
Water and solutes move from an area of high pressure to an area of low pressure
Filtration
Molecules that are unable to pass through the lipid bilayer combine with a protein carrier in the plasma membrane to cross the membrane. What type of transport is this?
Facilitated diffusion
The ability of a solution to change the shape of cells by altering their internal water volume
Tonicity
By which two ways do molecules cross the membrane in facilitated diffusion?
Bind to protein carriers in the membrane and are ferried across
Move through water filled protein channels
The solution contains the same number of solutes as the cell
Isotonic solution
The solution contains a higher number of solutes than the cell
Hypertonic solution
Which way does the water move in a hypertonic solution?
out of the cell
The solution contains a lower number of solutes than the cell
Hypotonic solution
Which way does the water move in a hypotonic solution?
into the cell
What happens to the cell when in an isotonic solution?
Maintain their shape and exhibit no loss or gain of water
What happens to the cell when in a hypertonic solution?
The cell loses water, shrinks, or crenates
What happens to the cell when in a hypotonic solution?
The cell plumps up rapidly as it fills with water until it bursts.
When a cell uses energy (ATP) to move solutes across the membrane against their concentration gradient
Active Processes
Two major means of active membrane transport
Active and Vesicular Transport
Type of transport where large particles are transported across the membrane with a vesicle using ATP
Vesicular transport
Moves substances from inside of the cell to the extracellular space
Exocytosis
Moves substances from the extracellular space to the inside of the cell
Endocytosis
The cellular material between the plasma membrane and the nucleus
Cytoplasm
Fluid substance inside the cell
Cytosol
The power house of the cell, where ATP is made, and contains its own DNA
Mitochondria
Organelle in the cell that is composed of proteins and ribosomal RNA and is the site of protein synthesis
Ribosomes
Ribosomes make proteins that are secreted from the cell or used in the membrane
Endoplasmic reticulum
Enzymes catalyze reactions involved with:
- Lipid metabolism and synthesis of cholesterol
- Make steroid based hormones
- Absorption, synthesis, and transport of fats
- Detoxification of drugs, certain pesticides, and carcinogens
- Breakdown of stored glycogen to form free glucose
Smooth endoplasmic reticulum
The smooth ER in skeletal and cardiac muscle cells
Sarcoplasmic reticulum
Major function is to modify, concentrate, and package proteins and membranes made at the rough ER
Golgi Apparatus
Sacs containing digestive enzymes, clean up debris in the cell
Lysosomes
Rods running through the cytosol, support the cell structure
Cytoskeleton
Small, barrel-shaped organelles oriented at right angles to each other. Organize the mitotic spindles in cell division. Form the bases of cilia and flagella
Centrioles
Fingerlike projections that move substances in one direction across the cell surface in one direction. Found in the nose and trachea
Cilia
Cell projection that moves the entire cell.
i.e tail of sperm
Flagella
The control center of the cell that contains our DNA
nucleus
Contains more than one nucleus
multinucleated
Name two types of cells that are multinucleated in the human body
Skeletal muscle cells and liver cells
Does not contain a nucleus; mature red blood cells
anucleated
The resting phase of the cell cycle
Period between cell formation and cell division
Not a phase in mitosis
Interphase
What has to occur before a cell can divide?
DNA must be replicated so the original cell’s genes will be passed on to future cells
Enzymes that untwists the DNA helix to make two strands of DNA that will be used as a template to make more DNA
Helicase
Bind to the nitrogen containing bases and are then used to bond the new complimentary strand to the old strand
DNA polymerases
What does adenine bind to in DNA replication?
Thymine
What does guanine bind to in DNA replication?
Cytosine
Which type of cells cannot divide and are only repaired with scar tissue?
Neural, skeletal, and heart muscle cells
What type of cells are reproduced continually?
Skin and intestinal lining
Which type of cells reproduce more slowly?
Liver cells, except if the organ is damaged
Cell division: division of the nucleus
Mitosis
Cell division: division of the cytoplasm
Cytokinesis
Four phases of mitosis
Prophase, metaphase, anaphase, and telephase
First and longest phase of mitosis
Prophase
What stage does this occur:
The centriole pairs separate
Mitotic spindles grow from the centrioles
As they grow, the push the centrioles farther apart, eventually ending up on opposite sides of the cell
The nuclear membrane starts to breakup allowing the spindles to interact with chromosomes
Prophase
What phase of mitosis:
Second phase of mitosis
Chromosome line up in the middle of the cell
Centromeres are in the exact center of the spindle (equator)
Metaphase
What stage of mitosis:
Third and shortest phase of mitosis
Centromeres of the chromosome split
Each chromatid becomes a chromosome (daughter chromosome)
Each chromosome is pulled toward the pole it faces
The cell elongates
Anaphase
What stage of mitosis:
Final stage Begins when chromosome movement stops Chromosomes uncoil and look like threads again Nucleus reappears Nuclear membrane forms
Telephase
Master blueprint for making all the proteins in our body
DNA
Segments of DNA that carries instructions for one protein
Genes
Name the nucleotide bases
Adenine, guanine, thymine, and cytosine
The three base sequence of nucleotides that form an amino acid
Triplet
What allows our cells to make different types of proteins needed?
Different sequences of nucleotide bases
How does DNA transfer information to the ribosomes to make proteins?
RNA
Single strand of nucleotides
Sugar is ribose
Bases are adenine, guanine, cytosine, and uracil
RNA
What are the three forms of RNA?
Transfer RNA (tRNA)
Ribosomal RNA (rRNA)
Messenger RNA (mRNA)
Form of RNA that is cloverleaf shaped; carries the amino acid
Transfer RNA (tRNA)
What form of RNA forms part of the ribosome?
Ribosomal RNA (rRNA)
What form of RNA consists of long nucleotide strands that look like half of DNA?
Messenger RNA (mRNA)
mRNA’s corresponding 3 base sequence
Codon
Type of RNA that helps mRNA bind to the ribosome
rRNA
Type of RNA that transfers amino acids to the ribosomes
tRNA
The amino acid is bound to the______ of tRNA?
Tail
What is bound to the head of tRNA?
Anticodon
Translation starts with what start codon?
AUG