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Biology Unit One Test Notes

Terms in this set (52)

Cell Theory
1. All living organisms are composed of a cell or cells
2. Cells are the basic unit of structure and function of all living organisms
3. All cells come from preexisting cells
Robert Hooke
An English scientist who used a microscope to examine cork (plant) and discovered cells. He gave the cells their name. (1665)
Anton van Leeuwenhoek
Observed tiny living organisms in drops of pond water through his microscope and called them animacules
Matthias Schleiden
A German botanist who discovered that all plants are composed of cells
Theodor Schwann
A zoologist who discovered that animals are made of cells in 1838
Rudolph Virchow
A German physician who stated that cells only come from other cells. His statement disproved the Theory of Spontaneous Generation. (1855)
How are unicellular organisms and multi-cellular organisms different?
Unicellular organisms are composed of only one cell, while multi-cellular organisms are composed of many cells
What are the differences/similarities in prokaryotes and eukaryotes?
- Only bacteria are prokaryotes
- Prokaryotes don't have a nucleus
- Prokaryotes don't have double-helical DNA. Their DNA floats freely.
- Prokaryotes don't have a nucleus or membrane-bound organelles
- Eukaryotes can be animal cells or plant cells.
- Eukaryotes have a nucleus and membrane-bound organelles
- Both have vacuoles and vesicles
Cell Wall
- A rigid structure surrounding (outside) the plasma membrane in plants, algae, fungi, and bacteria.
- Gives the cell structure, shape, and support.
- Made of cellulose
Cell membrane
- Encloses cell
- Serves as a barrier to the uncontrolled flow of water
- Contains proteins that are important to cell activity
- Controls what goes in and out of the cell via active and passive transport
Nucleus
- Control center of the cell
- The nuclear envelope contains thin fibers of DNA and protein called chromatin
- Rod-shaped chromosomes
- Contains nucleolus
Cytoplasm
- Holds the organelles in place
- Helps transport nutrients
Mitochondrion
- Produces high energy compound ATP from glucose (food, sugars)
- Contains its own DNA called mDNA
- Powerhouse of the cell
Endoplasmic Reticulum
- Complex network of transport channels
- Smooth ER has no ribosomes and functions in poison detoxification
- Rough ER has ribosomes and releases newly made protein from the cell
Ribosome
- Site of protein synthesis
- Ribosomes can be free-floating or attached to the rough ER
Golgi Body
- Series of flattened sacs that modifies, packages, stores, and transports materials out of the cell
Chloroplast
- The place where photosynthesis is carried out (energy from sunlight is made into food)
- Found in plants and algae
Vacuole
- Sacs that help in food digestion
- Helps the cell maintain its water balance
- Found mostly in plants and protists
- One big one in plants that holds water to keep the plant alive
Lysosome
- Recycles cellular debris
- Contains a variety of enzymes
- Helps digest food particles inside or outside the cell
- Digestion
Peroxisome
- Protects the cell from its own production of toxic hydrogen peroxide
- Contains oxidative enzymes that break down the hydrogen peroxide produced by the white blood cells into water and oxygen
- Breaks down and detoxifies
Nucleolus
- Produces ribosomal RNA which makes ribosomes
Differences in plant cells and animal cells
Plant cells have...
- Cell wall
- Chloroplasts and chlorophyll
- One large vacuole
- Rectangular/box shaped
- Make their own food through photosynthesis
- Usually no lysosomes

Animals cells have...
- No cell wall
-No chloroplasts or chlorophyll
- Many small vacuoles
- Round (irregular)
- Lysosomes
Similarities in plant cells and animal cells
- Cytoplasm
- Endoplasmic reticulum
- Ribosomes
- Golgi
- Mitochondria
- Nucleus
- Ribosomes
- Both eukaryotic cells
Mitosis
- A form of nuclear cell division whose purpose is to replicate cells. Mitosis replicates and divides original chromosomes in order to form two daughter cells that are identical to the parent cell and to each other.
- Phases: interphase, prophase, metaphase, anaphase, telophase, and cytokinesis.
Meiosis
- A form of cellular division which turns one copy of each homologous chromosome into gametes such as sperm and egg cells
- Produces four daughter cells, each with half the number of chromosomes of the parent cells. Daughter cells are similar to parent cells but not identical.
- From diploid to haploid
- Cells go through two divisions
- Phases: interphase, prophase I, metaphase I, anaphase I, telophase I, prophase II, metaphase II, anaphase II, telophase II, and cytokinesis.
Active Transport
- The movement of molecules or ions across the cell membrane into or out of the cell, against the concentration gradient
- Requires energy (ATP) and a membrane protein
Passive Transport
- The movement of molecules/substances across the cell membrane into or out of the cell, down the concentration gradient
- Requires no energy and no membrane protein
Facilitated Transport
- The movement of molecules/substances across the cell membrane into or out of the cell, down the concentration gradient
- Requires a membrane protein
- Requires no energy, therefore a form of passive transport
Diffusion
- The process by which a net amount of molecules move down the concentration gradient, from an area of high concentration to an area of low concentration
- A type of passive transport
- Molecules move freely across the cell membrane without the use of energy or a membrane protein
Osmosis
- The diffusion of water into or out of the cell through a semipermeable membrane from a solute of low concentration to a solute of high concentration
- A type of passive transport
- No energy or transport proteins required
- WATER ONLY
Proteins
Provide building blocks for tissues, transports other molecules and helps to regulate certain reactions in the human body. Catalysts.
Carbohydrates
Has the primary function of providing a rapidly available energy source for living things
What determines the sequence and arrangement of amino acids in a protein?
The ratio of carbon, hydrogen, and oxygen atoms in carbohydrates
On which of the organelles are proteins assembled?
Ribosomes
Which of the organelles serves as the cell's boundary from its environment?
Cell membrane
A student is examining a cell using a microscope. What observation about the cell indicates that it must be a plant cell?
Its boxlike shape
How does a eukaryotic organism differ from a prokaryotic organism?
The cells of a prokaryotic organism do not have membrane-bound organelles
What term describes the ability of an organism to maintain a relatively constant internal temperature?
Metabolism
What type of cellular transport requires a cell to use energy?
Active transport
In which type of cellular transport do molecules bind to channel proteins in order to move across a selectively permeable membrane against a concentration gradient?
Facilitated transport
How many amino acids are there?
Twenty
Which organelle can be likened to a cleanup crew for the cell?
Lysosomes
Which molecules carry genetic information from one generation to the next?
Nucleic acids
How do the offspring of asexual reproduction differ from those of sexual reproduction?
Cells produced through asexual reproduction are genetically identical to their parents
Which of the following occurs during meiosis but not mitosis?
The chromosome number is halved in sex cells
Which of the following is not a difference between lipids and carbohydrates?
A. Only one dissolves in water
B. Only one can be used as energy by a cell
C. One has more oxygen atoms than the other (C IS THE ANSWER)
D. One has more carbon-hydrogen bonds than the other
Which compounds join to form proteins?
Amino acids
Which of the following correctly pairs smaller molecules with the biological macromolecules they make up?
Amino acids and proteins; nucleotides and nucleic acids
A student is using a microscope to examine an unlabeled slide of a cell. Which of these structures suggest that the student is looking at a plant cell?
Chloroplasts and cell wall
Which of the following enable undifferentiated cells to become specialized cells?
Unique enzymes in each undifferentiated cell
Which of the following is a carbohydrate that serves as the main component of plant cell walls?
Cellulose
Within a cell, DNA provides the information needed for the cell to make proteins. Which of the following are the organelles that are most involved in these processes?
Nucleus and ribosomes
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