2A1 Ultrastructure Of Cells & Living Characteristics Flashcards
Gain understanding of diverse cellular structures in living organisms.
What is the basic unit of life that determines the activities of an organism?
A cell.
What are animal cells characterized by?
- Contain a nucleus.
- Contain membrane-bound organelles (e.g. mitochondria).
Animal cells are eukaryotic cells.
What is the function of the nucleus in cells?
It controls most cell activities, including metabolism, growth, and reproduction, and contains DNA.
Which organelle is present in both plant and animal cells and is responsible for the release of energy from glucose?
Mitochondria
Mitochondria are often referred to as the powerhouses of the cell because they generate most of the cell’s supply of adenosine triphosphate (ATP), used as a source of chemical energy.
What is the function of ribosomes in a cell?
Help synthesize proteins.
Ribosomes can be found floating freely within the cytoplasm or attached to the endoplasmic reticulum, forming the rough ER.
What fills the inside of a cell and covers the organelles?
Cytoplasm
It’s a jelly-like fluid.
Which part of the animal cell in the diagram controls what substances enter and leave the cell?
Plasma membrane
The plasma membrane is the outer boundary of a cell that separates it from the external environment.
Describe the structure of mitochondria.
- Oblong organelles.
- Have a highly-folded inner and an outer membrane.
- A gel-like material called the matrix.
The inner membrane in mitochondria folds to form a structure called the ‘cristae,’ while the outer membrane is even and porous. Mitochondria are responsible for releasing energy in the cell.
Describe the structure of the golgi apparatus.
- A membrane-bound organelle.
- Comprises a series of stacked, flattened discs called cisternae.
The Golgi apparatus helps package and secrete proteins in the cell.
What is the function of the Golgi body?
- Processes and modifies proteins received from the endoplasmic reticulum (ER).
- Packages proteins into vesicles.
What are organelles and what is their significance in plant & animal cells.
Structures that perform specific jobs, helping maintain cellular balance and keeping the cell alive.
What do lysosomes do in an animal cell?
They contain hydrolytic digestive enzymes that break down and recycle toxic substances and waste.
Why do animal cells lack a cell wall?
They do not require the rigidity and support that cell walls provide to plant cells.
How does the nucleus contribute to genetic information transfer?
It contains DNA and forms chromosomes that pass genetic information from parents to offspring.
Differentiate between rough ER and smooth ER.
- Rough ER: has ribosomes and aids in protein synthesis.
- Smooth ER: lacks ribosomes and helps in lipid synthesis and detoxification.
Ribosomes can be scattered within the cell or attached to the ER. Rough ER contains ribosomes, while smooth ER does not.
How do mitochondria differ in various cell types?
Heart & muscle cells have more mitochondria due to their constant need for energy, compared to cells like skin or bone cells.
What are the five characteristics of living things?
- Made up of cells.
- Capable of growth and development.
- Uses energy.
- Responds to stimuli.
- Able to reproduce.
How can we know if something is living?
By checking if it exhibits the five characteristics of living things.
Name a type of living thing that moves slowly.
Plants
Example: They move by opening and closing their petals.
What do all living organisms have in common at the cellular level?
They are all made up of at least one cell.
What is ATP?
Adenosine Triphosphate.
ATP is often called the energy currency of the cell. It stores and transfers energy needed for many cellular processes.
What is the role of glucose in living organisms?
It is converted into ATP through a series of chemical reactions.
How do some cells move?
By using structures like cilia or flagella.
What is the major energy source most cells use?
Glucose.
What is binary fission?
A method of asexual reproduction in cells.
Binary fission is most commonly seen in prokaryotic organisms like bacteria, where a single cell divides into two identical daughter cells.
Example: bacteria reproduce by binary fission.
What is one way to observe the cells of an organism?
Using a microscope.
Why are cells classified as living things?
Because it has all the characteristics of living things.
What is homeostasis?
The maintenance of a stable internal environment in living organisms.
What is the importance of responding to stimuli for living organisms?
It helps them adapt to their environment.
How do plants respond to a light stimulus?
Plants grow in the direction of their light source.
What is the difference between prokaryotic and eukaryotic cells?
- Prokaryotic cells do not have a nucleus.
- Eukaryotic cells have a nucleus.
Name an example of a single-celled organism.
Bacteria.
Give an example of homeostasis in humans.
Regulation of body temperature.
How do living things maintain homeostasis?
Through feedback mechanisms that balance internal conditions.
How do plants grow differently than animals?
- Plants grow continuously at their meristems.
- Animals grow until they reach a certain size.
Why is reproduction essential for living organisms?
It ensures the continuation of a species.
Define cellular differentiation.
It is the process of each cell’s shape and organelle makeup changing as it develops, according to their specific genetic instructions.
Differentiation allows cells to develop specific functions and structures, essential for the formation of various tissues and organs in multicellular organisms.
The diagram shows a plant cell.
Which organelle stores water, nutrients, and waste products?
The central vacuole.
The fluid inside the plant cell vacuole is called ‘cell sap’.
How do plant cells typically differ in shape compared to animal cells?
- Plant cells usually have a fixed, rectangular shape due to the rigid cell wall.
- Animal cells have a more flexible, round shape.
In which part of the plant cell diagram does photosynthesis take place?
The chloroplast.
Which part of the plant cell provides strength and support?
The cell wall.
Cellulose is the main component of the cell wall.
