Cell structure/ types Flashcards
Mitochondria
“cellular power plants” because they generate most of the cell’s supply of adenosine triphosphate (ATP), used as a source of chemical energy via aerobic respiration. They take in O2, and Glucose and expel, CO2 , H2O, and ATP
ATP
Adenosine triphosphate: energy within cells for metabolism. It is produced by photophosphorylation and cellular respiration and used by enzymes and structural proteins in many cellular processes
Cytoplasm
is the region between the cell membrane and the nucleus. All the contents of the cells of prokaryotic organisms (which lack a cell nucleus) are contained within the cytoplasm
Lysosome
(Recycling Center) organelles that contain acid hydrolase enzymes to break down waste materials and cellular debris. They can be described as the stomach of the cell
Smooth Endoplasmic Reticulum
is involved in the synthesis of lipids, including oils, and fats (liver/muscle cells) and steroids (ovary/teste cells), and detoxification of drugs and poisons (liver cells)
Ribosome
(workbenches) Not an organelle (no membrane) synthesizes protein chains. It assembles the twenty specific amino acid molecules to form the particular protein molecule determined by the nucleotide sequence of an RNA molecule. Ribosomes are divided into two subunits. The smaller subunit binds to the mRNA and then the roughER. (some remain ‘free’ and unattached)
Golgi Complex
(Distribution Center) receive Transport Vesicles and their modified proteins from RER. They are sorted and addressed, and some further modified. The proteins exit either out of cell, to cell membrane or into cytoplasm.
Transport Vesicle
(shuttles) membrane-lined spheres that transport proteins or molecules through cytosol via the microtubules.
Endomembrane System
group of membrane-lined organelles and transport vesicles in Eukaryotes
Aerobic Respiration
The breakdown of glucose to ATP using Oxygen within mitochondria. Oxygen (breathed in) + Glucose (eaten) = CO2 (exhaled) + Water + ATP (energy)
Free Ribosomes
Ribosomes that do not attach to the RER. They synthesize proteins using mRNA/tRNA for use within the cell (usually)
RNA (4 types)
mRNA- messenger RNA, transcribe the DNA code for a particular protein in nucleus, exit via pores, enter ribosome.
tRNA- transfer RNA, enter ribosome and match nucleotides with mRNA bonding their attached amino acids to form protein chain.
rRNA- ribosomalRNA used to make Ribosomes
microRNA- small RNA chains that halt translation by binding to the mRNA and cutting it in half
Nucleus (4 parts)
Nuclear Envelope: double membrane that confines the DNA and Nucleus
Nucleolus: Center of Nucleus that synthesizes rRNA
Nuclear Pores: Exits from Nucleus
DNA: cookbook of information for assembling proteins.
Flagella
Tail-like extensions that function for cell movement. (only animal flagella is sperm cell tail) They are extensions of the microtubules.
Cilia
Hair-like growths that move very rapidly for propelling cell, or moving material around cell. Common among single-celled organisms.
Cytoskeleton (3 sizes)
- Microfilaments: small fibers that reach out for movement or to capture prey. (pseudopodium)
- Intermediate Filaments: most stabilizing of cytoskeleton.
- Microtubules: largest, determine shape of cell. Act as monorails for organelles movement.
Cytosol
Gel-like liquid (mostly water) within the Cytoplasm. The matrix.
Organelle
Membrane bound, highly organized internal structure of a cell that performs a specific function. Specific to Eukaryotes
Prokaryotes Characteristics
Bacteria and Archaea DNA not enclosed (naked chromosomes) Much smaller than Eukaryotes single-celled Ribosomes Cell Wall Cell Membrane Flagella (sometimes)
Eukaryotes Characteristics
DNA enclosed within a Nucleus (membrane-lined) Much larger than Prokaryotes Multi-cellular (mostly) Compartmentalized Organelles (many types)
Virus
Alive/Not Alive debate
Largest Virus much smaller than smallest bacteria
cannot reproduce without using machinery of other cells
Nucleotides (3 parts)
- Phosphate Group the rails
- Sugar (deoxyribose)
- Nitrogen-containing base (4): Adenine(A) , Guanine(G), Cytosine(C), Thymine(T). the rungs
Nucleic Acids
DNA and RNA
Plant Cells have….. Animal Cells don’t
Cell Walls, Chloroplasts, Central Vacuole
Gap Junctions
Communication channels between adjacent cells in animals that open only as necessary.
Centriole
Cluster of microtubules that, during mitosis, pull DNA pairs apart to separate cells
channel protein
a type of pore in the cell membrane that channels molecules or ions across the membrane through the protein.
carrier protein
protein that selectively combine with ion or substance to help it move across the membrane. Think of a key fitting into a lock
fluid-mosaic model
a phospholipid bilayer has a fluid consistency similar to oil, allowing lipid molecules the freedom to move. Proteins embedded on the outside or within the bilayer form a mosaic pattern
glycolipids
are phopholipids that have attached carbohydrate (sugar) chainsglyco=sugar
glycoproteins
have attached carbohydrate (sugar) chainsglyco=sugar
selectively permeable
the fluid-mosaic membrane is selectively permeable because some small molecules can pass through the phospholipid bilayer but larger molecules cannot
Active Transport
Transport of a substance across a membrane that does not rely on the potential energy of a concentration gradient for the substance being transported and therefore requires and addititonal energy source (often ATP)
Amphipathic Molecule
A molecule containing both hydrophobic and hydrophilic regions.
Concentration Gradient
A difference in the concentration of a substance from one point to another, as for example, across a cell membrane.
Diffusion
The net movement of particles (atoms, molecules, or ions) from a region of higher concentration to a region of lower concentration, resulting from random motion.
Endocytosis
The active transport of substances into the cell by the formation of invaginated regions of the plasma membrane that pinch off and become cytoplasmic vesicles.
Exocytosis
The active transport of materials out of the cell by fusion of cytoplasmic vesicles with the plasma membrane.
Facilitated Diffusion
The passive transport of ions or molecules by a specific carrier protein in a membrane.
Gated Channel
Channel proteins that open or close based on the presence or absence of a physical or chemical stimulus.
Hypertonic Solution
A term referring to a solution having an osmotic pressure (or solute concentration) greater than that of the solution with which it is compared
Hypotonic Solution
A term referring to a solution having an osmotic pressure (or solute concentration) less than that of the solution with which it is compared.
Integral Protein
A protein that is tightly associated with the lipid bilayer of a biological membrane.
Isotonic Solutions
Solutions that have identical concentrations of solute molecules and hence the same osmotic pressure.
Ligand
A molecule that binds to a specific site in a receptor or other protein.
Osmosis
The net movement of water by diffusion through a selectively permeable membrane from a region of higher concentration of water to a region of lower concentration of water.
Passive Transport
The diffusion of a substance across a biological membrane.
Peripheral Protein
A protein associated with one of the surfaces of a biological membrane.
Phagocytosis
Literally, “cell eating”; a type of endocytosis by which certain cells engulf food particles, microorganisms, foreign matter, or other cells.
Pinocytosis
Cell drinking; a type of endocytosis by which cells engulf and absorb droplets of liquids.
Receptor-Mediated Endocytosis
A type of endocytosis in which extracellular molecules become bound to specific receptors on the cell surface and then enter the cytoplasm enclosed in vesicles.
Selective Permeability
Allowing some substances to cross more easily than others.
Sodium-Potassium Pump
Active transport system that transports sodium ions out of, and potassium ions into, cells.
Transport Protein
A protein that helps molecules or ions pass through lipid bilayer membranes.
Define a tissue.
- aggregation of similar cells and intervening extracellular matrix that serve specific function
- group of similar cells and surrounding extracellular matrix and extracellular fluid (also known as ‘intercellular’)
Name the four main tissue types.
- epithelia
- connective tissue
- muscles
- nervous tissue
Define organ.
- groups of tissues that are assembled into units that serve broad bodily functions
- ie: bones, skin
Cells perform these seven general functions (also list the associated cells):
- Movement (muscle cells)
- Conductivity (nerve cells)
- Metabolic absorption (kidney and intestinal cells)
- Secretion (mucous gland cells)
- Excretion (all cells)
- Respiration (all cells)
- Reproduction (most cells)
What are seven membrane proteins in the cytoplasmic membrane?
Channel Proteins
Enzyme Receptors Receptor Sites Identifier Proteins Carrier Proteins
Define: Metabolism
The sum of all physical chemical changes that occur in the body.
Define: anabolism
The building of larger substances from smaller substances, such as the building of proteins from amino acids.
Define: catabolism
The breakdown of larger molecules into smaller ones that the body can use for its own needs.
The three stages of cellular respiration:
Glycolysis Krebs (citric acid cycle, tricarboxylic acid cycle)Electron Transport System
Define: oxidation
Utilization of glucose by the cell
Cytoplasmic membrane
Contains cellular contents; regulates what enters and leaves the cell
Nucleus
Contains genetic information; control center of the cell
Protons
in nucleus, positive charge
Neutrons
in nucleus, no charge
Electrons
orbit nucleus, negative charge
1st valence shell
holds 2 electrons
2nd, 3rd, 4th, etc shells
holds up to 8 electrons
Chemical bonds
formed to stabilize atoms
Ions
charged atoms
Ionic bond
bond between 2 ions of opposite charges
Hydrogen bond
attraction of hydrogen atoms of one molecule to an atom of another molecule; it’s a weak bond
Chemical reactions
a substance are changed into one or more new substances
Synthesis reaction
builds, requires energy- A + B –> AB
Decomposition reaction
breaks apart- AB –> A + B
Exchange reaction
synthesis & decomposition reactions both involved- AB + CD –> AD + CB
Reversible reaction
chem bonds can be made and can be broken down- AB A + B
Atomic #
of protons
Atomic mass
of protons and neutrons
Acid
donates hydrogen ions when dissolved in water; proton donator
Base
donates hydroxide ions when dissolved in water; proton acceptor
Salt
dissolves into cations & anions when dissolved in water; formed when acids & bases react
pH scale 0-14
7 on pH scale more hydroxide (OH-) ions, more basic/alkaline
7 on pH scale equal # of OH- and H+ ions, neutral
Human blood on pH scale
7.35-7.45
Interphase
cell prepares for mitosis, DNA & chromosomes duplicate
Prophase
chromosomes condense, nuclear envelope disassembles
Metaphase
chromosomes align along equator, spindle fibers attach to duplicated chromosomes
Anaphase
spindle fibers contract to separate duplicated chromosomes
Telophase
nuclear envelope reforms around 2 groups of identical chromosomes
Cytokinesis
cytoplasm of one cell is divided into two daughter cells
Mitosis
division of nucleus and chromosomes- stages: prophase, metaphase, anaphase, telophase
Peroxisomes
detoxifies harmful substances (alcohol) and breaks down lipids in liver/kidneys
Osmosis
water molecules diffuse in an attempt to equalize concentration on both sides of membrane
Facilitated transport
molecules move from area of HIGH TO LOW concentration with help from a transport protein
Active transport
molecules move from area of LOW TO HIGH concentration against concentration gradient, requires ATP
Phagocytosis
eating of worn out cells, bacteria, viruses
Exocytosis
material moved out of cell by being pinched off; membrane sac formed around it & it fuses w/ cell membrane
Cellular respiration
process of converting food molecules into ATP
Aerobic respiration
oxidation of molecules in presence of oxygen, in mitochondria; very efficient
Anaerobic respiration
oxidation of molecules in absence of oxygen, in mitochondria; less efficient
Isotonic solution
solution outside cell has equal amount of dissolved solutions in cell
Inorganic compounds
lack carbon, simple structure; dissolve in water
Organic compounds
always contains carbon and usually hydrogen; dissolve in organic liquids (ie. alcohol)
Carbohydrates
-function: fuel; -structure: C, H, O, monosaccharides are basic bldg block
Monosaccharide
one sugar molecule; simple sugars (ie. glucose in blood sugar)
Disaccharide
two sugar molecules bonded together (ie. glucose + fructose = sucrose aka table sugar)
Polysaccharide
many sugar molecules bonded together; complex carbs (ie. starches- storage form of sugar in plants)
Proteins
-function: support, energy source, antibodies, bio catalyst; -structure: C, H, O, N, S, amino acids are bldg blocks; made in ribosomes
Amino acids
-structure: amino group- NH2, carboxyl group- COOH, hydrogen atom, r-group- gives amino acid unique properties, bonded to central carbon atom
Nucleic acids
-structure: C, H, O, N, P, bldg blocks are nucleotides; -function: has code for genetic info
Nucleotides
composed of a 5 carbon sugar (deoxyribose), nitrogenous base, phosphate group;
Process inside the nucleus when the DNA code is “copied” as an mRNA molecule forms
Transcription
Genetic material of he cell that carries the chemical “blueprint” of the body (2 words)
Deoxyribonucleic Acid
A nucleic acid found in the cytoplasm that is crucial to protein sysnthesis (2 words)
Ribonucleic Acid
One pair of tiny cylinders in the centrosome of a cell
Centriole
A beadlike structure that attaches one chromatid to another during the early stages of mitosis
Centromere
Condition in which cells change in orientation to each other and fail to differentiate into specialized cell type
Anaplasia
Synthesis of a protein in cytoplasm by ribosomes
Translation
Amino acids of the nearly 100 found in nature are used to build body protein. Proteins are used in the formation of:
Hormones Enzymes Plasma proteins Muscle proteins Hemoglobin Most cell membranes
Arrange the phases of mitosis in the correct sequence:
- Interphase 2. Prophase 3. Metaphase 4. Anaphase 5. Telophase
Nucleic acids are composed of units called nucleotides that have three parts. The nucleotides for DNA are:
Sugar (Deoxyribose) Phosphate group (PO4) Bases-- -Adenine (A) -Thymine (T) -Cytosine (C) -Guanine (G)
What is the system of bonding known as complementary base pairing?
Adenine can only pair with thymine (A-T).
Cytosine can only pair with guanine (C-G)
RNA is also a nucleotide that is composed of three parts:
Sugar (ribose) Phosphate group (PO4) Bases-- -Cytosine (C) -Guanine (G) -Adenine (A) - Uracil (U)
DNA directs the function of each protein cell
True. In addition to carrying genetic code, DNA also directs the function of cellular proteins
What type of division occurs in sex cells?
Meiosis
In meiosis, how many times does the cell divide, and how many cells do you get from the division(s)?
The cell divides twice, leaving you with four new cells.
What is the order of stages in meiosis?
Interphase, prophase, metaphase, anaphase, telophase, prophase 2, metaphase 2, anaphase 2, telophase 2, cytokinesis.
What happens during the interphase stage of both meiosis and mitosis?
cell carries on normal functions- growing, respiration, making proteins;2/3 of cell life happens in this stage; DNA (chromatin) and centrioles replicate.
What happens during prophase(1)?
Chromatin becomes chromosomes (sister chromatids); nucleus disappears; centrioles move to opposite poles; spindle forms (in meiosis crossing over occurs)
What parts of the cell are important for cell division ans what is their function?
centrioles-Centrioles are involved in the organization of the mitotic spindle and in the completion of cytokinesis. [5] Centrioles were previously thought to be required for the formation of a mitotic spindle in animal cells. However, more recent experiments have demonstrated that cells whose centrioles have been removed via laser ablation can still progress through the G1 stage of interphase before centrioles can be synthesized later in a de novo fashion .[6] Additionally, mutant flies lacking centrioles can develop almost normally, although the adult flies lack flagella and cilia, a lack that underscores the requirement of centrioles for the formation of these organelles Cells whose centrioles have been removed via laser ablation or genetic manipulation lack aster microtubules. These cells often fail to undergo proper asymmetric cell division, as the aster microtubules help to position the spindle within the cell. chromatids- A chromatid is one among the two identical copies of DNA making up a replicated chromosome, which are joined at their centromeres, for the process of cell division (mitosis or meiosis). The term is used so long as the centromeres remain in contact. When they separate (during anaphase of mitosis and anaphase 2 of meiosis), the strands are called sister chromatids. ribosomes-Ribosomes are the workhorses of protein biosynthesis, the process of translating mRNA into protein. The mRNA comprises a series of codons that dictate to the ribosome the sequence of the amino acids needed to make the protein. Using the mRNA as a template, the ribosome traverses each codon (3 nucleotides) of the mRNA, pairing it with the appropriate amino acid provided by a tRNA. Molecules of transfer RNA (tRNA) contain a complementary anticodon on one end and the appropriate amino acid on the other. The small ribosomal subunit, typically bound to a tRNA containing the amino acid methionine, binds to an AUG codon on the mRNA and recruits the large ribosomal subunit. The ribosome then contains three RNA binding sites, designated A, P, and E. The A site binds an aminoacyl-tRNA (a tRNA bound to an amino acid); the P site binds a peptidyl-tRNA (a tRNA bound to the peptide being synthesized); and the E site binds a free tRNA before it exits the ribosome. Protein synthesis begins at a start codon AUG near the 5’ end of the mRNA. mRNA binds to the P site of the ribosome first. The ribosome is able to identify the start codon by use of the Shine-Dalgarno sequence of the mRNA in prokaryotes and Kozak box in eukaryotes
How many chromosomes does each cell end up with in meiosis and mitosis?
Quantity In humans, for example, there are normally 23 pairs of homologous chromosomes in each cell (N=23). However, the quantity of chromatids will be a multiple of 23. It can be either 4N, 2N or 1N. N does not refer to haploid or diploid; it refers to the number of chromatids in the cell as a multiple of the haploid number of chromosomes for the organism. For example, because a human haploid germ cell has 23 chromosomes, then “N” refers to a multiple of 23. (e.g. 2N=46 chromatids). The last is only seen in haploid gametes, with only one of each homologous chromosome pair. Such are created in gametogenesis. [edit] 4N In a cell with 4N chromatids, there are 23 chromosome pairs (46 chromosomes), and each chromosome has 2 chromatids. Thus, there are 92 chromatids in each cell (4N). It occurs after the S phase of interphase. (See cell cycle). [edit] 2N Immediately after a mitosis, where a cell has divided in two, but not yet duplicated its DNA in S phase, there are still 23 chromosome pairs (46 chromosomes). However, each chromosome only has one chromatid. Thus there are 46 chromatids (2xN) Alternatively, a haploid cell with two chromatids per chromosome also has 46 chromatids. However, this doesn’t occur naturally in human somatic cells. [edit] 1N Immediately after meiosis, each cell, called a gamete, only has half the number of chromosomes (23 chromosomes). Furthermore, each chromosome only has one chromatid. Thus, there are 23 chromatids (1xN)
What are the stages of mitosis?
interphase, prophase, metaphase, anaphase, telophase, cytokinesis. ( I predict Molly ate two crabs)
What does mRNA do?
Messenger ribonucleic acid (mRNA) is a molecule of RNA encoding a chemical “blueprint” for a protein product. mRNA is transcribed from a DNA template, and carries coding information to the sites of protein synthesis: the ribosomes. Here, the nucleic acid polymer is translated into a polymer of amino acids: a protein. In mRNA as in DNA, genetic information is encoded in the sequence of nucleotides arranged into codons consisting of three bases each. Each codon encodes for a specific amino acid, except the stop codons that terminate protein synthesis. This process requires two other types of RNA: transfer RNA (tRNA) mediates recognition of the codon and provides the corresponding amino acid, while ribosomal RNA (rRNA) is the central component of the ribosome’s protein manufacturing machinery
Cell division for producing gametes (eggs or sperm) is called
MEIOSIS
Cell division for growth is called
MITOSIS
Chromosomes are long and string-like when..
cells are NOT dividing
The first step in either MITOSIS or MEIOSIS is for the long string-like chromosomes to…
thicken and shorten
How many daughter cells do we get from MITOSIS
TWO
IN MEIOSIS the daughter cells have __________ the number of chromosomes of the original cell
half
Which type of cell division is basically ‘cloning’ a cell (making an exact copy)
MITOSIS
TRUE OR FALSE:
ALL the daughter cells from meiosis will have identical DNA
FALSE
How many chromosomes does a human body cell have?
46
How many chromosomes does a human egg cell have?
23
TRUE OR FALSE:
During BOTH mitosis and meiosis, the chromosomes double and look like ‘x’s
TRUE
A chromosome is …
A structure found inside the nucleus of a cell which carries some of the instructions for the organism. A chromosome has many genes (sections that relate to a specific trait)
trait means …
characteristic
e.g. hair colour, adult height, type 1 diabetes
recessive means …
if an allele (form of a gene) is recessive, then BOTH genes must be the same for the trait to be expressed.
e.g., Only bb would code for blue eyes
dominant means …
if an allele (form of a gene) is dominant, then only ONE copy is needed for the trait to be expressed.
(The other copy of the gene can be the same or different)
e.g., BB OR Bb might code for brown eyes
allele means …
form of a gene. E.g., blue eyes and brown eyes are two alleles for the gene that codes for eye colour
what is a gene?
A gene is a part of a chromosome that codes for a specific trait
(e.g. the gene might be the instruction set for an amino-acid chain that may be used in making the pigment in brown eyes)
If yellow eyes are dominant and red eyes are recessive, how would a scientist write the genotype for a red-eyed animal?
yy
the letter used is by convention/tradition the first letter of the dominant trait
If Gray fur is dominant and blue fur is recessive, what colour fur would a creature with the genotype Gg have?
Gray fur
What is Mm: a genotype or a phenotype?
Genotype (genotypes are always represented by letters)
Genotype ratio shows the expected fraction or percentage of each ___________ in the offspring of a cross.
genotype
Homozygous
when both of the alleles for a trait are the same
Heterozygous
when an individual has difference alleles for a trait
Phenotype
the physical expression of the genotype
Pleioptropic genes
genes that affect many different characteristics
multiple allelism
When traits are determined by more than two alleles
Polygenic traits
Such is the case when more than one gene is responsible for the creation of a trait
epistatic traits
When a gene interferes with the expression of another, masking the effect.
Gene Linkage
when two (or more genes) are on the same chromosome and consequently linked
