Bio Flashcards
What is the primary component of the plant cell wall?
Cellulose
The plant cell wall provides structural support and protection.
What is the primary component of the fungi cell wall?
Chitin
Chitin provides strength and rigidity to the cell wall of fungi.
What is the primary component of the prokaryotic cell wall?
Peptidoglycan
Peptidoglycan is essential for maintaining the structural integrity of prokaryotic cells.
What function does the plasma membrane serve in a cell?
Prevents the cell from bursting if it takes in too much water via osmosis
The plasma membrane regulates the movement of substances in and out of the cell.
What defines the nucleoid in prokaryotic cells?
A single circular DNA molecule that floats free in the cytoplasm
The nucleoid contains the genetic material of prokaryotes.
What is a defining feature of prokaryotic cells?
No nucleus
Prokaryotic cells lack membrane-bound organelles, including a nucleus.
What are plasmids?
Extra DNA that is circular and floats free in the cytoplasm
Plasmids can carry genes that confer advantageous traits, such as antibiotic resistance.
What can plasmids code for?
Properties such as antibiotic resistance
Plasmids can enhance survival by allowing bacteria to withstand antibiotics.
How can plasmids be transferred between prokaryotes?
Through processes such as bacterial conjugation
Bacterial conjugation allows the exchange of plasmids, contributing to genetic diversity.
What is the shape of the DNA found in the nucleoid of prokaryotic cells?
Irregularly shaped
The circular DNA in prokaryotes is not enclosed in a nucleus and has a distinct shape.
True or False: Bacterial cells often contain several plasmids.
True
Plasmids in bacteria can replicate independently of the main chromosomal DNA.
Fill in the blank: The _______ draws bacteria to another during replication of plasmid.
Pilus
The pilus facilitates the transfer of plasmids between bacterial cells.
What is the first rule for drawing from a microscope?
DRAW ONLY WHAT YOU SEE!!
What medium must all drawings from a microscope be done in?
Pencil
How should drawings from a microscope be characterized in terms of size and clarity?
Large and clear
What type of lines should be used when drawing from a microscope?
Distinct lines
What should NOT be used when illustrating darker areas on a specimen?
Shading
Which type of microscope uses light and lenses to focus the image?
Light microscope
Which type of microscope uses electrons and electromagnets?
Electron microscope
What determines the resolution in a light microscope?
Wavelength of light
What type of specimen is typically used with a light microscope?
Thin specimen
What is the environment required for an electron microscope?
Vacuum
What is the image format produced by a light microscope?
Virtual image in eye
What is the staining agent commonly used for specimens in a light microscope?
Iodine
What is a key disadvantage of electron microscopes compared to light microscopes?
High cost, not portable, lots of training
What type of screen does an electron microscope use to display images?
Fluorescent screen
Fill in the blank: A light microscope uses _______ to focus the image.
light
Fill in the blank: An electron microscope uses _______ to focus the image.
electrons
True or False: Specimens for electron microscopes are usually stained with iodine.
False
What are the two main types of microscopes discussed?
- Light microscope
- Electron microscope
What is the resolution in an electron microscope determined by?
Wavelength of electrons
What should be avoided in microscope drawings instead of using distinct lines?
Sketching
What is a notable feature of the light microscope regarding its cost and portability?
Low cost, portable
What type of specimen preparation is required for an electron microscope?
Stained with lead citrate or other heavy metal
What’s the outer layer of a ovum membrane
Zona pelicula
Structure of a sperm call
Head contains acrosome enzyme digests zone pelcula
Mid piece contains mitochondria for energy
Red blood cell
Bioconcave shape large surface area
No nucleus for hemoglobin
What are white blood cells involved in?
Defence against disease
White blood cells, also known as leucocytes, play a crucial role in the immune system.
What is a type of white blood cell that is the most common?
Neutrophils
Neutrophils are a primary component of the immune response.
What feature of neutrophils allows them to travel to the site of infection?
Multi-lobed nuclei
This structural adaptation enables neutrophils to squeeze through small gaps.
What characteristic of neutrophils contributes to their mobility?
Highly motile
Neutrophils actively move towards sites of infection.
What do the lysosomes in the cytoplasm of neutrophils contain?
Hydrolytic enzymes
These enzymes are essential for digesting pathogens during phagocytosis.
What process do neutrophils use to digest pathogens?
Phagocytosis
Phagocytosis is the mechanism by which neutrophils engulf and destroy pathogens.
What are the two types of lymphocytes?
T-cells and B-cells
Both types of lymphocytes play distinct roles in the immune response.
What is a notable feature of lymphocytes?
Large nucleus
Lymphocytes are characterized by their prominent nucleus.
What is one function of T-cells?
Send signals to B-cells and destroy infected/cancerous cells
T-cells play a crucial role in coordinating the immune response.
What can B-cells differentiate into?
Plasma cells and memory cells
Plasma cells produce antibodies, while memory cells remain in the blood for faster re-infection response.
What do plasma cells produce?
Antibodies
Antibodies are crucial for identifying and neutralizing pathogens.
What is the role of memory cells?
Remain in the blood until re-infection
Memory cells enable a quicker immune response upon subsequent exposure to the same pathogen.
What structures are seen with an electron microscope?
Ultrastructure.
What do eukaryotic cells contain?
Organelles, which are structures in cells with specialised functions often enclosed by a membrane.
What is the function of the plasma membrane?
Protects the cell from its surroundings and regulates the movement of substances in and out of cells.
What is a vesicle?
A small, membrane-bound sac that transports and stores substances in the cell.
What is the nucleolus?
A region of dense DNA and protein that makes ribosomes.
What is the rough endoplasmic reticulum (RER)?
A series of single, flattened sacs enclosed by a membrane with ribosomes on the surface, where proteins are made.
What is the nucleus?
Surrounded by a double membrane (envelope) with pores (holes) in the nuclear envelope.
What are centrioles?
Two hollow cylinders arranged at right angles to each other that make the spindle in cell division.
What is the smooth endoplasmic reticulum (SER)?
A series of single, tubular sacs made of membrane where lipids are made.
What is a mitochondrion?
Surrounded by a double membrane (envelope) with an inner membrane folded into finger-like projections called cristae, containing 70S ribosomes and DNA, and is the site of respiration.
What is a lysosome?
Enclosed by a single membrane containing digestive enzymes that destroy old organelles and pathogens.
What are 80S ribosomes?
The site of protein synthesis, in contrast with 70S in prokaryotes.
What is the Golgi apparatus?
A series of single, curved sacs enclosed by a membrane that modifies proteins and packages them in vesicles for transport.
What is the cytoplasm?
The fluid that fills a cell, containing many molecules dissolved in solution (enzymes, sugars, amino acids, fatty acids) and is the site of many metabolic processes.
What are prokaryotes?
Organisms made of a single cell with no membrane-bound organelles.
What is the structure of plasmids?
Double-stranded DNA in a circular structure.
What do plasmids often contain?
Additional genes that aid the bacterium’s survival, such as antibiotic resistance or toxin producing genes.
What is the function of ribosomes in bacteria?
Makes proteins.
What does the ‘S’ in 70S ribosomes stand for?
Svedberg, a measure of size by rate of sedimentation.
What is the capsule in bacteria?
A polysaccharide layer outside the cell wall.
What are the functions of the capsule?
- Protects cells from drying out
- Helps cells to stick to surfaces
- Protects against engulfment by white blood cells.
What is the nucleoid in bacteria?
Region where single circular length of DNA is folded.
What is the cell wall in bacteria made of?
A long-chained molecule made up of sugar and amino acids called peptidoglycan.
How do gram-negative bacteria differ from gram-positive bacteria regarding staining?
Gram-negative bacteria do not retain the gram stain when washed with acetone and absolute alcohol.
Why do gram-positive bacteria retain the gram stain?
Because the thick peptidoglycan wall absorbs the stain.
Which type of bacteria is more resistant to antibiotics?
Gram-negative bacteria.
What contributes to the antibiotic resistance of gram-negative bacteria?
Their cell wall has an outer membrane which protects them from antibiotics.
Fill in the blank: Bacteria are ______, made of a single cell with no membrane-bound organelles.
prokaryotes.
True or False: Gram-positive bacteria have an outer membrane.
False.
