Cell Structure And Transport Flashcards
What is the development period of light microscopes?
Mid-17th century
Light microscopes were first developed during this time.
What is the maximum magnification of light microscopes?
2000x
This indicates the highest level of detail achievable with light microscopes.
List the parts of light microscopes.
- Eyepiece
- Objective lens
- Stage
- Slide
- Light
- Fine focus
- Coarse focus
These components work together to allow observation of specimens.
When were electron microscopes developed?
1930s
This advancement allowed for more detailed observation of subcellular structures.
What is the maximum magnification of electron microscopes?
2,000,000x
This significant increase in magnification provides greater detail than light microscopes.
What type of images do transmission electron microscopes provide?
2D images
These microscopes are known for high magnification and resolution.
What type of images do scanning electron microscopes provide?
3D images
Scanning electron microscopes offer a different perspective with lower magnification.
Fill in the blank: To calculate the magnification of a light microscope, you multiply the magnification of the eyepiece lens by the magnification of the _______.
objective lens
This is a standard method for determining magnification in microscopy.
What formula is used to calculate the size of an object in microscopy?
magnification = size of image/size of real object
This formula is often represented as IAM in a triangle format.
Define resolving power in microscopy.
Affects how much detail it can show
Higher resolving power allows for clearer images.
Define resolution in the context of microscopy.
The ability to distinguish between two separate points
This is crucial for identifying fine details in specimens.
What controls all activities of the cell?
Nucleus
The nucleus contains genes within chromosomes that carry instructions for protein synthesis.
What is the function of the cytoplasm?
Liquid gel where organelles are suspended and where most chemical reactions take place
The cytoplasm supports organelles and facilitates biochemical processes.
What is the role of the cell membrane?
Controls the passage of substances in and out of the cell
It regulates movement of substances like glucose and mineral ions.
Where does aerobic respiration take place in the cell?
Mitochondria
Mitochondria release energy necessary for cellular functions.
What is the site of protein synthesis in the cell?
Ribosomes
Ribosomes produce all proteins needed in the cell.
What is the function of the cell wall in plant cells?
Strengthens the cell and provides support
The cell wall is made of cellulose.
What do chloroplasts contain and what is their function?
Contain chlorophyll, absorb light to make food by photosynthesis
Chloroplasts are essential for converting light energy into chemical energy.
What is the purpose of the permanent vacuole in plant cells?
Filled with cell sap, important for keeping cells rigid to support the plant
The vacuole helps maintain turgor pressure within the cell.
Fill in the blank: The _______ controls the passage of substances like glucose and mineral ions.
cell membrane
True or False: Ribosomes are responsible for aerobic respiration.
False
Mitochondria are responsible for aerobic respiration.
Fill in the blank: The _______ is made of cellulose and strengthens the plant cell.
cell wall
What are examples of eukaryotic cells?
Animal and plant cells
Eukaryotic cells have complex structures including organelles.
What key components are found in eukaryotic cells?
Cell membrane, cytoplasm, genetic material in a nucleus
The genetic material in eukaryotic cells is DNA, which forms chromosomes.
What is the size range of eukaryotic cells?
10-100um in length
Eukaryotic cells are generally larger than prokaryotic cells.
What defines prokaryotic cells?
They are small, lack a nucleus, and have a single DNA loop
Prokaryotic cells also include structures like plasmids and a cell wall.
Give an example of a prokaryotic cell.
Bacteria
Bacteria are the most common type of prokaryotes.
What is the size range of prokaryotic cells?
0.2-2um in length
Prokaryotic cells are significantly smaller than eukaryotic cells.
What are the additional structures that may be found in prokaryotic cells?
Plasmids, slime capsule, flagella
These structures can provide additional functions, such as movement or protection.
True or False: Most bacteria are harmful.
False
Most bacteria are helpful and play essential roles in ecosystems.
What is an order of magnitude?
A way to compare numbers or objects by powers of 10
If one number is about 10 times bigger than another, it is an order of magnitude larger.
Fill in the blank: Eukaryotic cells have genetic material called _______.
DNA
DNA is organized into structures known as chromosomes.
What is the process by which cells gain different subcellular structures to carry out specific functions?
Differentiation
Cells become specialised through differentiation, which allows them to perform particular jobs.
At what stage do most animal cells differentiate?
Early stage
Unlike plant cells, which can differentiate throughout life, animal cells usually do so at an early stage.
What are nerve cells specialised for?
Carrying electrical impulses
Nerve cells allow rapid communication to occur in different parts of the body.
What adaptation do nerve cells have for making connections to other nerve cells?
Dendrites
Dendrites allow nerve cells to connect with other cells.
What is the purpose of the axon in a nerve cell?
Carries the nerve impulse
The axon transmits the nerve impulse from one location to another.
What are nerve endings adapted to do?
Pass the impulse to another cell
Nerve endings use special transmitter chemicals and contain mitochondria for energy.
What are muscle cells specialised to do?
Contract and relax
Muscle cells work together in tissues called muscles to create movement.
What type of muscle cells work in pairs to create movement?
Striated muscle cells
Striated muscle cells are responsible for voluntary movements.
What do smooth muscle cells do in the digestive system?
Contract to squeeze food through the gut
Smooth muscle cells form one of the layers of tissue in the digestive system.
What special proteins do muscle cells contain that allow them to contract?
Proteins that slide over each other
These proteins facilitate the contraction of muscle fibres.
Why do muscle cells contain many mitochondria?
To transfer energy needed for contraction
Mitochondria provide the energy required for muscle cells to contract and relax.
What do muscle cells store that can be used in cellular respiration?
Glycogen
Glycogen can be broken down to provide energy during cellular respiration.
What is the primary function of sperm cells?
Fertilising an egg cell
Sperm cells carry genetic information from the male parent.
What adaptation helps sperm cells move quickly?
Long tail
The tail of the sperm cell allows for swift movement towards the egg.
What is found in the middle section of a sperm cell that provides energy for its tail?
Mitochondria
Mitochondria supply the energy required for the sperm’s movement.
What does the acrosome in a sperm cell store?
Digestive enzymes
These enzymes help break down the outer layers of the egg during fertilisation.
What does the large nucleus in a sperm cell contain?
Genetic information
The nucleus carries genetic material to be passed on to the offspring.
What is the primary function of root hair cells?
To take up water and mineral ions efficiently
Found close to the tips of growing roots and close to xylem tissue.
How do mineral ions enter root hair cells?
By active transport
What is one adaptation of root hair cells that increases water uptake?
Large surface area available for more water to move into the cell
What role does the large permanent vacuole play in root hair cells?
Speeds up the movement of water by osmosis from soil to root hair cell
Why do root hair cells contain many mitochondria?
To transfer the energy needed for active transport
What is the primary function of photosynthetic cells?
To make their own food by photosynthesis
What do chloroplasts in photosynthetic cells contain?
Chlorophyll that traps light needed for photosynthesis
How are photosynthetic cells positioned to maximize light absorption?
In continuous layers in the leaves and outer layers of the stem
What is the function of the large permanent vacuole in photosynthetic cells?
Keeps the cell rigid as osmosis takes place
What is the primary function of xylem cells?
To carry water and mineral ions from the roots around the plant
What happens to xylem cells when they are formed?
They are alive when first formed but lignin builds up in spirals in the cell wall
What structural feature do xylem cells have that aids water transport?
Long hollow tubes that allow water and mineral ions to move easily
How do spirals and rings of lignin benefit xylem cells?
Make the xylem cells strong and help withstand the pressure of water
What is the primary function of phloem cells?
To carry food made by photosynthesis around the plant
What structural feature allows phloem cells to transport dissolved food?
Sieve plates formed by the breakdown of cell walls between cells
How do phloem cells maintain their function despite losing internal structures?
Supported by companion cells that help keep them alive
What is the role of mitochondria in companion cells?
Transfer the energy needed to move dissolved food
What is diffusion?
Diffusion is one of the main ways that the body takes in and gets rid of dissolved substances and gases from the cells across the cell membrane.
Define diffusion.
Diffusion is the spreading out of the particles of a gas, or any substance in a solution (a solute), resulting in a net movement from an area of high concentration to an area of low concentration.
What causes diffusion?
Diffusion occurs because of the random movement of particles which bump into each other and move them everywhere.
What factors affect the rate of diffusion?
The rate of diffusion is affected by three factors:
* difference in concentrations (concentration gradient)
* temperature
* available surface area
How does the concentration gradient affect diffusion?
The bigger the difference in concentrations, the steeper the concentration gradient and the faster the rate of diffusion.
How does temperature affect the rate of diffusion?
Higher temperatures cause particles to move around more quickly, resulting in more rapid diffusion.
Why is available surface area important for diffusion?
A greater available surface area increases the area over which diffusion can take place, thereby increasing the rate of diffusion.
How is net movement calculated in diffusion?
Net movement equals the particles moving in minus the particles moving out.
What types of substances move in and out of cells by diffusion?
Dissolved substances that move in and out of the cells by diffusion include simple sugars, gases, and waste products.
Give an example of diffusion in the human body.
An example of diffusion is when oxygen passes from the air in the lungs into the red blood cells through cell membranes.
What is gas exchange?
Gas exchange is the diffusion of oxygen and carbon dioxide in opposite directions in the lungs.
Fill in the blank: Oxygen moves down a concentration gradient from the blood cells into _______.
body cells
True or False: Carbon dioxide moves from body cells into the air in the lungs by diffusion.
True
What is osmosis?
The movement of water from a high concentration to low concentration across a partially permeable membrane.
Only some types of particles can pass through the membrane.
Define dilute in terms of solute and solvent concentration.
High concentration of solvent (water) and low concentration of solute (sugar).
Define concentrated in terms of solute and solvent concentration.
Low concentration of solvent (water) and high concentration of solute (sugar).
What is the effect of osmotic gradients on body cells?
Water can move into or out of the cell, affecting its function.
What does isotonic mean in relation to cell concentration?
The concentration of solutes in the solution outside the cell is the same as the internal concentration.
What happens to a cell in a hypertonic solution?
The cell shrivels as water leaves the cell by osmosis.
What is the consequence of a hypertonic solution on the cytoplasm?
The cytoplasm becomes too concentrated as water leaves the cell.
What describes a hypotonic solution in relation to the cell?
The concentration of solutes in the solution outside the cell is lower than the internal concentration.
What happens to a cell in a hypotonic solution?
The cell swells and may burst as water moves in by osmosis.
What is the result of a cell using up water in chemical reactions?
The cytoplasm becomes more concentrated, leading to a hypotonic environment outside the cell.
Fill in the blank: Osmosis occurs across a _______ membrane.
partially permeable
What do plants rely on for support in their stems and leaves?
Osmosis
Osmosis helps the vacuole swell, pressing the cytoplasm against the cell wall.
What happens to the pressure in a plant cell when water moves in?
Pressure builds up until no more water can enter the cell, known as turgor.
What is turgor?
The pressure that makes the cell rigid and keeps the leaves and stems firm.
What type of solution is needed for plant cells to remain turgid?
Hypotonic solution.
What characterizes a hypotonic solution?
Lower concentration of solutes and a higher concentration of water than the cells.
What occurs when a plant cell is in a hypertonic solution?
Water leaves by osmosis, causing cells to become flaccid.
What does it mean for a plant to become flaccid?
The cells are not firm and swollen due to lack of pressure on the cell walls.
What is the effect of losing turgor in a plant?
The plant wilts as turgor no longer supports the plant tissues.
What is plasmolysis?
The process where more water is lost by osmosis, causing the vacuole and cytoplasm to shrink.
What happens to the cell membrane during plasmolysis?
The cell membrane pulls away from the cell wall.
Can plasmolysis be observed outside of laboratory experiments?
No, it can usually only be seen in laboratory experiments.
What is active transport?
Active transport is when substances needed by a cell have to be moved against a concentration gradient across a partially permeable membrane.
How do cells absorb ions through active transport?
Cells can absorb ions from very dilute solutions, moving substances like sugars and ions through the cell membrane.
What is required for active transport to occur?
Energy is needed for active transport, which is supplied by cellular respiration.
How are the rates of respiration and active transport related?
The rate of respiration and the rate of active transport are closely linked.
What happens when a cell respires and releases a lot of energy?
It can carry out lots of active transport.
Give an example of cells involved in active transport.
Root hair cells in plants and the cells lining the gut are examples.
What cellular structure do cells involved in active transport usually have many of?
Cells involved in active transport usually have many mitochondria.
Why is active transport important for plants?
It allows plants to absorb mineral ions from very dilute solutions in the soil against a concentration gradient.
How does active transport function in the gut and kidney tubules?
Active transport moves glucose out of the gut and kidney tubules into the blood, often against a large concentration gradient.
Why is glucose absorption crucial for cellular respiration?
Glucose is needed for cellular respiration, so as much of it is absorbed out of the gut as possible.
Fill in the blank: Active transport is used to move glucose from the gut into the blood against the _______.
concentration gradient.
What does the surface area to volume ratio allow?
Sufficient transport of molecules into and out of the cell to meet the needs of the organism
How does a small object affect the surface area to volume (SA:V) ratio?
Large surface area to volume ratio allows simple diffusion for material exchange
What happens to the surface area to volume ratio as organisms get larger?
It decreases, making material exchange difficult
What are the consequences of a low surface area to volume ratio in larger organisms?
Gases and food molecules cannot reach every cell; metabolic waste cannot be removed quickly
What adaptations enhance the effectiveness of an exchange surface?
• Large surface area
• Thin membrane
• Efficient blood supply
• Ventilation
Describe the adaptation of the Australian Fitzroy river turtle for gas exchange.
Has large sacs lined with finger-like folds for surface area and rich blood supply, ventilated by muscular openings
Why are alveoli in the lungs important for gas exchange?
They have an enormous surface area and a rich blood supply
What role do villi in the small intestine play?
Provide a large surface area and short diffusion paths for effective material exchange
How do plant roots adapt to enhance water and mineral ion uptake?
Have a large surface area to increase efficiency
What adaptations do plant leaves have for effective gas and solute exchange?
• Flat and thin structure
• Presence of air spaces
• Stomata
Fill in the blank: The effectiveness of an exchange surface can be increased by having a _______.
[large surface area]
True or False: Larger organisms do not need specialized surfaces for material exchange.
False
What maintains a steep concentration gradient in cells of plant roots?
Constant movement of water away from the roots
