Biology Flashcards
What is a Cell?
A cell is the smallest, basic unit of life. Each cell contains smaller parts called organelles that have special functions that maintain all the life processes of the cell. All living things are made of cells. There are two types of cells: animal and plant. An average cell is 100 um in diameter.
what are the 12 organelles
cell membrane, cytoplasm, nucleus, vacuoles, mitochondria, lysosomes (A), golgi, SER and RER, ribosomes, centrioles (A), cell wall (P), chloroplast (P)
and cytoskeleton - not an organelle
cell membrane
- Every cell has a cell membrane that forms a protective barrier around the cell
- The cell membrane is made of a double layer of lipids
- A lipid is a fat-like molecule that does not dissolve in water - The cell membrane is designed to allow different substances to move through it (semipermeable)
- One process for moving substances across the cell membrane is diffusion
- When a substance is present in different concentrations on either side of the cell membrane, the particles diffuse from an area of high concentration to an area of lower concentration
cytoplasm
- Cytoplasm is a jelly-like substance that fills the cell and surrounds the organelles
-The organelles are suspended in the cytoplasm - Cytoplasm contains the nutrients required by the cell to carry on its life processes
- The physical nature of the cytoplasm allows the nutrients and organelles to move within the cell
nucleus
- The control centre organelle of the cell, controlling all the activities in a cell, including growth and reproduction
- The nucleus is surrounded by the nuclear envelope, which contains pores to allow the transport of materials to go in and out
- Most nuclei also contain a small dense area called the nucleolus
- The nucleus contains nearly all of the cell’s DNA. DNA stands for deoxyribonucleic acid.
- DNA is very important to the cell because it contains the coded information for making proteins and other molecules. It also guides the growth, development, and functioning of living organisms.
vacuoles
- Vacuoles and vesicles (smaller vacuoles) are membrane-bound organelles/sacs that store nutrients, wastes, and other substances used by the cell
- In plant cells, the central vacuole stores water for the cell
- When water enters the cell, the central vacuole swells, causing the plant cell to become firm - Vesicles transport substances throughout the cell
mitochondria
- All cells require a source of energy: mitochondria supply that energy and is the powerhouse of the cell
- Have a double membrane with finger-like cristae
- Reactions occur in these organelles to convert the chemical energy in sugar into energy that the cell can use
lysosomes (A)
- Where digestion takes place
- They are small organelles that are filled with digestive enzymes to break down the things the cell doesn’t need
- An enzyme is a protein that can speed up chemical reactions in the cell - Lysosomes also break down invading bacteria and damaged cell organelles
- Essentially, they work as the clean-up system in the cell
golgi apparatus
- Receives proteins from the endoplasmic reticulum
- Modifies, sorts, and packages these proteins for delivery throughout the cell or outside of the cell.
- Looks like a stack of flattened membranes
endoplasmic reticulum
- Made of a series of interconnected small tubes that carry materials through the cell
-
Rough endoplasmic reticulum (RER), a series of folded membrane spotted with ribosomes, is associated with making proteins
- Ribosomes are small, dense-looking organelles that may be attached to the RER or free in the cytoplasm
- Ribosomes are where proteins are made -
Smooth endoplasmic reticulum is associated with the production of fats and oils
- Smooth endoplasmic reticulum does not have ribosomes
- Forms containers called transport vesicles that are used to move things around inside the cell
cytoskeleton
- It is an internal network of fibres made up of protein filaments
- It helps maintain the cell’s shape
centrosome & centrioles
- coordinates movement of chromosomes during mitosis
- help maintain cell shape and structure
- ANIMALS ONLY
cell wall
- The cell wall is a rigid frame around the cell that provides strength, protection, and support
- PLANTS ONLY
chloroplast
- Contain a green substance called chlorophyll
- Chlorophyll uses energy from the sun to convert carbon dioxide and water into sugar and oxygen in a process called photosynthesis. - The chloroplast is made up of little sacs known as thylakoids
- Thylakoids are stacked together in a way that resembles a stack of coins.
- They are surrounded by a thick fluid called stroma.
- A stack of thylakoids is called a granum; chloroplasts may have many grana.
- Known as being “solar collectors” because they collect light energy from the Sun, which is used during the process of photosynthesis to produce carbohydrates.
- The carbohydrates are used for the growth of the plant.
Differences between Plant and Animal Cells:
(6)
- Cell walls and chloroplasts are only found in plant cells.
- Plant cells contain a specialized chemical compound called chlorophyll, a pigment that makes photosynthesis possible.
- Plant cells have a large central vacuole. Vacuoles in animal cells tend to be small.
- Some plant cells store energy in the form of starch or oils, such as cornstarch and canola oil. Animal cells store energy in the form of glycogen, a carbohydrate, or as lipids in the form of fats.
- Animal cells have centrioles. Plant cells do not have centrioles.
- P form cell plate during mitosis!
Virus Vs. Bacteria:
- Bacteria are single-celled, living organisms
- Do not depend on a host to reproduce
- Treated with antibiotics
- Bigger than viruses →diameter of 1000 nm
- Viruses are tiny, infectious particles
- Only reproduces by infecting a host cell (and are therefore not considered living)
- Not a cell, just packages of nucleic acid and protein
- 20-300 nm
study animal & plant cell diagrams + practice labelling
what is tissue
A group of cells that function together as a unit.
what is an organ
A group of tissues that structurally form a functional unit specialized to perform a particular function.
biological organization
(Atoms/Macromolecules) → Organelle → Cell → Tissue → Organ → Organ System → Organism
what are the 6 specialized cells
- RBC
- WB
- Nerve cell (axon)
- Cells in the trachea (goblet cells)
- Sperm cells
- Muscle cells
RBC
- No nucleus
- Carries oxygen (O₂) and carbon dioxide (CO₂)
- Shape allows it to flow smoothly in blood vessels
- Made in bone marrow
WBC
Receptor on surface helps cell to recognize invaders
Nerve Cell (axon)
- Long “body” of cell allows for fast transmission
- The many “arms” allow for many functions
cells in trachea (goblet cells)
- Cilia (hair) can trap and move dust
- Cells produce mucus to trap dust
- Tall, can pack a lot
- cystic fibrosis
sperm cells
- Shape of head allows it to move/swim effectively
- Tail allows motion
- Many mitochondria give energy for swimming
muscle cells
- Longer cells that are bundled together so they can contract with force
what are the 4 main tissues in animals
epithelial, muscle, connective, nerve
Epithelial Tissue:
- Made of cells that are tightly packed together to form a protective barrier (one cell thick or contain several layers)
- Lines body cavities and outer surface of body
- Forms glands that produce hormones, enzymes, and sweat
- The 3 types: squamous, cuboidal, or columnar
muscle tissue
- Allows for movement by contracting and relaxing
- The 3 types: cardiac (in the heart - involuntary), smooth (blood vessels, stomach, organs - involuntary), and skeletal (voluntary)
connective tissue
- Joins other tissues together, supports and protects structures
- Types: tendons (muscles to bones), ligaments (bones to bones), bones, cartilage, and blood, fat cells
- Blood is made of plasma, red blood cells, white blood cells, and platelets (cells that help in the process of blood clotting) - Forms blood, stores fat, fills empty space
nerve tissue
- Made of nerve cells
- Responds to stimuli (helps you feel pain)
- Transmits and stores information
- Ex. brain’s neurons