Flashcards in Test 1 Deck (53)
What are the four major biological macromolecules?
Carbohydrates, lipids, proteins, and nucleic acids.
Carbs provide energy. Lipids store energy and provide structure to cells. Proteins preform chemical reactions. Nucleic acids provide genetic information for cells.
Why is water necessary for cells to perform life functions?
Water accounts for approximately 2/3s of every cell. Water forms essential bonds with carbon, which is the element necessary for life and the site of all chemical reactions within a cell.
What is the difference between an enzyme and a catalyst?
A catalyst is any substance that can instigate or accelerate a chemical reaction while remaining unchanged.
An enzyme is a specific type of catalyst that accelerates chemical reactions among biological macromolecules. They are specialized to catalyze specific reactions within a living organism.
What is the function of chlorophyll in photosynthesis?
Chlorophyll is a pigment found within a chloroplast (a specialized organelle found in plant cells). It absorbs and traps light energy, which is then used by the chloroplasts to provide energy to break down carbon dioxide and water in order to produce glucose.
What are the major stages of cellular respiration?
1. Glucose and oxygen enter the cell 2. Glucose is broken down into smaller molecules. 3. The molecules and oxygen move into the mitochondria where the molecules and oxygen combine to farther break down glucose and release hydrogen. 4. Mitochondria release chemical energy to be delivered to other parts of the cell. 5. Excess heat, water, and carbon dioxide are released as a byproduct.
What is the difference between chemosynthesis and photosynthesis?
Chemosynthesis is the process of creating organic molecules (such as glucose) WITHOUT the use of LIGHT energy. It uses chemical energy from inorganic compounds, such as sulfur.
Photosynthesis RELIES ON LIGHT energy from the sun.
Why are cell membranes composed of lipids?
Lipids are generally composed of fatty acids and glycerol. Their chemical arrangement prevents them from mixing with water. This allows the lipids within the cell membrane to maintain and regulate the barrier between water within the cell and water outside of the cell.
Why are bacteria considered prokaryotic cells?
The term prokaryotic means before nucleus and bacteria does not contain a true nucleus cells.
Which organelles differentiate plant cells from animal cells?
Plant cells contain chloroplast, cell walls, and vacuoles (in the cytoplasm, store nutrients and waste), while animal cells do not.
How does the cytoskeleton provide a cell with shape and structure?
A cell's cytoskeleton is comprised of a network of filaments microtubules. These filaments and microtubules are made of different types of proteins. The interlocking nature of these structures provides the cell with its shape and stability and can also expand or contract to change the cell's shape to enable movement.
What is the difference between active and passive transport?
Passive transport moves materials without the use of energy while active transport does use energy.
What role do proteins play in cell communication?
Proteins act as receptors and senders of cell signals, passing and modifying the signals as they move throughout the cell to their target destination on the signaling pathway. Once the target protein receives the signals, it can trigger and direct the cellular response to the signals.
What role does diffusion play in photosynthesis?
As photosynthesis produces oxygen molecules, the concentration of oxygen molecules within the plant becomes greater than on the outside. The oxygen molecules move (or diffuse) to the area of low concentration outside of the cell.
What occurs in a cell if a particle is too large to be transported through the cell membrane?
If the cell is trying the get a large particle in, it will undergo endocytosis. Meaning it will wrap the membrane around the outside particle and move the encased material within the cell. If the cell needs to get rid of a large particle, it will perform exocytosis. Here, the particle will wrap the particle with a membrane. That membrane will then attach to the cell membrane and push the particle out.
Why do cells in multicellular organisms divide?
Cell division occurs in multicellular, eukaryotic organisms in order to grow the organism's size, specialize in specific functions during the organism's development, and repair aged and damaged cells.
What is the function of a checkpoint in the life cycle of a eukaryotic cell?
Checkpoints use internal and external environmental cues to decide whether or not to complete division. The three major checkpoints are the G1, G2, and the spindle checkpoints.
What is the difference between mitosis and meiosis?
Mitosis is the process of cell division in eukaryotic cells that result in two genetically identical daughter cells. Meiosis is the process of cell division in sexually producing organisms in which the cells divide twice to result in four sex cells that each contain half of the normal amount of chromosomes.
What occurs during the three main stages of interphase in the cell cycle?
The three main stages of interphase are Gap 1 (G1), Synthesis (S), and Gap 2 (G2).
G1: Cell growth and protein production
S: DNA duplication
G2: continue growth and protein production in preparation for mitosis.
What is the difference between meiosis I and meiosis II?
In meiosis I, the parent cell contains two copies of each chromosome pair, or homolog. The cell divides into two daughter cells, which each contain two copies of one homolog of each pair (4 chromosomes in two cells).
In meiosis II, the two daughter cells are divided again, this time with one set of chromosomes. (4 cells, each with 1 chromosome)
How are strands of DNA held together in a double helix?
What are the rules of base pairing in DNA?
adenine pairs with thymine, and guanine pairs with cytosine
Why is RNA important?
Ribonucleic acid (RNA) molecules are responsible for synthesizing protein and transmitting genetic information. There are three major types:
1. mRNA (messenger RNA): carries information from DNA
2. rRNA (ribosomal RNA): forms ribosomes for protein synthesis
3. tRNA (transfer RNA): brings mRNA to the ribosomes
What is the difference between DNA and RNA?
DNA: double stranded, deoxyribose, Thymine
RNA: single stranded, ribose, Uracil
What are the steps of DNA replication?
Initiation: DNA double helix unwinds by breaking hydrogen bonds.
Elongation: new strand begins to grow and replicate according to base pairs.
Termination: two new double helices close off and repair any errors
What are the stages of protein synthesis?
Transcription: mRNA copies genetic information from DNA strand
Translation: mRNA information is decoded and used to guide the creation of new proteins.
How do transcription factors help ensure that DNA is transcribed correctly during protein synthesis?
The wide variety of protein molecules can either activate or repress the transcription of genetic material by binding the RNA polymerase to the DNA of the gene.
What is the purpose of RNA splicing?
A stage of mRNA processing. Introns (noncoding DNA) are removed from the chain and leave behind the exons (regions that can be coded for protein synthesis).
What role do codons play in the translation process?
During translation, codons are transcribed by mRNA and decoded by tRNA into a sequence of amino acids in the protein.
How does regulation of gene expression impact cell differentiation?
Gene expression regulation relies on internal and external factors and ensures that the correct genes are activated at the appropriate time. When internal/external cues is needed for specialized cells, the appropriate genes are activated or repressed to trigger the cell to develop the specialized need.