Unit 1 - Biology Flashcards
Which organelles are found in a plant cell, but not in an animal cell?
- Cell wall
- Chloroplast
- Tonoplast
- Amyloplast
What is the function of the golgi apparatus?
- Modifying/sorting/packaging proteins
- Lipid transport in cells
- Formation of lysosomes
What are the two types of epithelial tissues?
Squamous and columnar
Give an example of an epithelial squamous tissue
Alveolar epithelium (Gas exchange)
Give an example of epithelial columnar tissue
Goblet cells and ciliated cells in the lungs (protecting lungs from pathogens)
What are pathogens?
Disease causing microorganisms
Give an example of endothelial tissue
Blood vessels in the cardiovascular system
Name the lifestyle factors that increase the risk of atherosclerosis
- Smoking cigarettes
- Drinking alcohol
- Lack of exercise
- Diet with too much fat/cholesterol/carbohydrate/salt
- Stress
Explain why myelinated axons allow nerve impulses to travel faster than unmyelinated axons
- Myelinated axons have Schwann cells and nodes of Ranvier
- This means that the action potential impulse jumps from one node to the next
- This is called saltatory conduction
- Depolarisation happens only at the nodes meaning a greater speed of nerve impulse
How are ribosomes in eukaryotic and prokaryotic cells different?
E - Larger 80s
P - Smaller 70s
What organelles are involved in protein synthesis in eukaryotic cells?
- rER (rough endoplasmic reticulus)
- Golgi apparatus
Vesicles for secretion
How is magnification calculated?
M = I/A
How is image size calculated?
I = A x M
How is actual size calculated?
A = I/M
How do you convert millimetres into micrometres?
x 1000
1mm = 1000 micrometres
What is the function of the slime capsule in prokaryotic cells?
- Stop desiccation
- Protection
Name two types of microscopy, which gives more detail?
Light microscopes
Electron microscopes - gives greater detail
Function of the Golgi apparatus
- Modifying proteins
- Packaging proteins into vesicles
Function of plasma (cell) membrane
Regulates the transport of materials into and out of the cell
What is a vesicle?
A small, spherical membrane bound sac which transports materials around the cell or out of the cell
Function of ribosomes
Responsible for protein synthesis (attached to ER in eukaryotic cells)
Function of lysosomes
Vesicles that contain hydrochloric enzymes. They break down waste material inside the cell
Function of smooth ER
Synthesise carbohydrates and lipids
Structure of smooth ER
Network of membrane bound, flattened sacs called cisternae
Function of cytoplasm
Site of metabolic reactions
Structure of rough ER
Network of membrane bound, flattened sacs called cisternae studded with ribosomes attached
Function of rough ER
- Synthesises proteins
- Transports protein
Function of the nucleus
Contains genetic information and controls/regulates metabolic cell activity
Function of nucleolus
Produces ribosomes and RNA
Structure of nucleolus
Dense spherical structure inside the nucleus
Function of the centrioles
Form spindle fibres that move chromosomes during cell division
Function of the mitochondrion
Site of aerobic respiration
Structure of the plasma (cell) membrane
Phospholipid bilayer, with proteins embedded in the layer
Structure of cytoplasm
Thick, gelatinous, semi-transparent fluid
Structure of the nucleus
- Largest organelle
- Surrounded by nuclear envelope
- Nuclear pores to allow movement of molecules
- Contains chromatin
- Nucleolus
Structure of Golgi apparatus
Stack of membrane bound flattened stacks (not attached)
Structure of mitochondria
- Two membranes
- Inner membrane highly folded to form cristae
- Central part is called the matrix
- Can be seen as long or spherical in shape
Structure of centrioles
Small tubes of protein fibres
Structure of cell wall (eukaryotes)
- Made of cellulose
- Sieve like structure
Function of cell wall (eukaryotes)
Protects and supports each cell and the whole plant
Structure of a chloroplast
- Double membrane
- Filled with fluid called stroma
- Inner membrane is a continuous network of flattened sacs called thylakoids
- A stack of thylakoids is called a granum (grana for plural)
- Grana contain chlorophyll (photosynthetic pigment)
Function of a chloroplast
Site of photosynthesis
Light energy trapped by the chlorophyll and used to produce carbohydrate molecules from water and carbon dioxide
Structure of tonoplast
Partially-permeable membrane of the vacuole
Function of tonoplast
Selectively permeable to allow small molecules to pass thorough
Structure of amyloplast
Double membrane-bound sac containing starch granules
Function of amyloplast
Responsible for the synthesis and storage of starch granules
Structure of plasmodesmata
Microscopic channels which cross the cell walls of plant cells
Function of plasmodesmata
Enable transport and communication between individual plant cells
Structure of pits
Pores in cells walls of the xylem
Function of pits
Allow water to enter and leave xylem vessels
Structure of cell wall (prokaryotic)
Cell wall made of peptidoglycan
Function of cell wall (prokaryotic)
Protects and supports each cell
Structure of the capsule
Slippery layer outside the cell wall of some species of bacteria
Function of capsule
Protects the cell and prevents desiccation
Structure of ribosomes in prokaryotic cells
Smaller than ribosomes found in eukaryotic cells. They consist of two sub-units and are not surrounded by a membrane
Function of ribosomes (prokaryotic)
Protein synthesis occurs at the ribosomes
Structure of nucleoid
- Nucleoid means nucleus-like
- Irregularly shaped region that holds the nuclear material with a nuclear membrane
- Where genetic material is localised
- DNA forms one circular chromosome (free-floating)
Function of a nucleoid
- Region where genetic information can be found
- Control cellular activity
Structure of a plasmid
Small loops of DNA
Function of a plasmid
Carry genes that may benefit the survival of the organism
How can you tell the difference between gram positive and gram negative cells?
- Carry out Gram staining
- Involving crystal violet, iodine, alcohol, safranin
- Gram positive are purple from the crystal violet
- Gram negative are pink from the safranin stain
- This is because gram negative have thinner walls so the initial stain is removed by alcohol wash
Where are palisade mesophyll cells found?
Upper side of the leaf
What is the function of palisade mesophyll cells?
Photosynthesis
How are palisade mesophyll cells adapted to their function?
- Packed with chloroplasts to absorb sunlight for photosynthesis
- Chloroplasts can move around cytoplasm to maximise the amount of sunlight they can absorb
- Found near the surface of the leaf
Where are root hair cells found?
- Plant cell
- Near the growing tip of plant roots
What is the function of root hair cells?
Movement of water and minerals from the soil into the plant root
How are root hair cells adapted to their function?
- Large surface area to maximise movement of water and minerals into the plant root from the soil
- Thin cellulose walls
- Vacuole containing cell sap with a low water potential
What is a sperm cell?
Male gamete (sex cell) in animals
What is the function of a sperm cell?
Deliver genetic information to the egg cell (female gamete) - fertilisation
How is a sperm cell adapted to its function?
- Undulipodium - tail like structure to allow movement
- Many mitochondria to provide energy by respiration for movement
- Acrosome enzyme to digest the protective layer around the egg cell
How big is a human sperm cell?
Mid-piece tail is 7 micrometres long and the end is ~40 micrometres long. The sperm head is 3 micrometres wide and 4 micrometres long
What is an egg cell?
Female gamete (sex cell) in animals Also known as ova
How big is an egg cell in humans?
It is one of the largest cells in the human body, approximately 0.12mm in diameter
What is the function of an egg cell?
Contains genetic information to join with sperm cell in fertilisation
How is an egg cell adapted to its function?
- Nucleus which holds genetic material
- Zona pellucida provides outer protective layer/membrane of the egg
- Corona radiate (two or three layers) which provides proteins needed by the fertilised egg cell
What is the function of red blood cells?
Carry oxygen around the body (needed for cellular respiration)
How are red blood cells adapted to their function?
- Biconcave shape (both sides concave inwards) meaning increased surface area to volume ratio
- Flexible to squeeze through narrow blood capillaries
- No nucleus or organelles to increase space for haemoglobin (which carry oxygen)
Give another name for red blood cells
Erythrocytes
Give another name for white blood cells
Neutrophils
What is the function of white blood cells?
Immune system - fight infection by digesting pathogens (disease causing microorganisms)
How are white blood cells adapted to their function?
- Multi-lobed nuclei which enables them to squeeze through small gaps when travelling to the sit of infection
- Cytoplasm holds lysosomes which contain enzymes used to digest pathogens that are ingested by the neutrophil
What are the 4 main types of tissue in animals?
Epithelium
Muscle
Connective
Nervous
What are the 3 types of epithelial tissues in animals?
- Squamous epithelial tissue
- Columnar epithelial tissue
- Endothelium tissue
Describe the structure of squamous epithelial tissue
Made up of flattened, specialised squamous epithelial cells
1 cell thick
Lining tissue
What is the function of squamous epithelial tissue?
Rapid diffusion
Give an example of squamous epithelial tissue and how it’s adapted to its function
Alveoli in the lungs – short diffusion pathway to allow rapid oxygen diffusion into the blood and carbon dioxide into the lungs
What is COPD? (what does it stand for)
Chronic Obstructive Pulmonary Disorder
Name a cause of COPD
Smoking
Describe the stages leading to COPD
- Epithelium cells can be damaged by smoking
- Smoke irritates and causes inflammation and scarring of the epithelium tissue in the lungs
- Alveoli walls become thicker due to scaring and produce more mucus
- Damage to air sacs causes emphysema and lungs lose natural elasticity
- This causes symptoms such as: breathlessness, persistent coughing, phlegm
