Chapter 1: Cells Flashcards
1
Q
What is a cell?
A
A cell is a unit of life. It consists of a mass of living matter called protoplasm
2
Q
Protoplasm
A
- a complex jelly-like substance
- made up of cell surface membrane, cytoplasm and nucleus
- where many chemical activities that ensure survival and growth of cell take place
3
Q
Cell surface membrane
A
- surrounds cytoplasm of cell
- made out of lipids and proteins
- a partially permeable membrane : only allowing some substances to pass through
- controls movement of substances in & out of the cell
4
Q
Cell Wall
A
- only present in plant cells (may be present in a few animal cells like bacteria)
- made out of cellulose
- protects the cell from injury and gives the plant cell a fixed shape
- fully permeable (does not control the type of substances that entre/leave the cell)
5
Q
Cytoplasm
A
- jelly-like substance that fills the inside of the cell and is enclose by cell surface membrane
- part of protoplasm between cell membrane and nucleus
- where most cell activities occur
- contains organelles which are cellular structures that performs a specific job within cell
6
Q
Parts of cytoplasm
A
- Cell membrane
- Smooth Endoplasmic Reticulum (SER)
- Mitochondrion
- Nucleus
- Vacuole
- Golgi Body
- Vesicle
- Rough Endoplasmic Reticulum (RER)
- Ribosomes
- Cytoplasm
7
Q
Nucleus
A
- surrounded by nuclear membrane
- contains genetic information in the form of chromosomes
- controls cell activities such as cell growth and the repair of worn-out parts
- essential for cell division
- w/o nucleus, cell are unable to divide
8
Q
Chromosomes
A
- long thread-like structure found in nucleus
- made up of proteins and deoxyribonucleic acid (DNA)
- DNA carries instructions that a cell needs for carrying our its activities
- when cell is dividing, chromosomes condense and shorten to become thick, rod-shaped structures
9
Q
Rough Endoplasmic Reticulum (RER)
A
- consist of a network of flattened spaces lined with a membrane
- surface is rough because of ribosomes that is attached to its surface
- outer surface of RER is continuous with nucleus membrane
- transports proteins made by ribosomes to the Golgi body for secretion out of the cell
10
Q
Ribosomes
A
- small round structures
- attached to RER or lie freely in cytoplasm
- needed to synthesise proteins in the cell
- ribosomes attached to the RER make proteins that are actually transported out of the cell
- ribosomes lying freely in the cytoplasm make proteins that are used within the cytoplasm of that cell
11
Q
Smooth Endoplasmic Reticulum (SER)
A
- does not have ribosomes attached to it
- more tubular than RER
- connected to RER
- synthesises substances such as fats and steroids
- converts harmful substances into harmless substances through detoxification
12
Q
Golgi Body (Golgi Apparatus)
A
- shaped like a disc
- consists of a stack of flattened spaces surrounded by membranes
- vesicles can be seen fusing with one side of the Golgi body and pinching off from the opposite side
- it chemically modifies substance made by the ER
- it stores and packages these substances in vesicles for secretion out of the cell
13
Q
How substances made by ER are moved out of the cell
A
- Vesicles transports substances within the cell. Small vesicles containing substances made by ER are pinched off from ER
- Vesicles then fuse with the Golgi body and release their contents in Golgi Body. The substances made by ER may be modified inside Golgi Body
- Secretory vesicles containing these modified substances are pinched off from the golgi body. They then move to the cell membrane
- Secretory vesicles fuse with the cell membrane and their contents are released out of cell
14
Q
Mitochondria
A
- small oval/ sausage-shaped organelles
- where aerobic respiration occurs, which releases energy
15
Q
Chloroplasts
A
- oval structures found in plant cells
- contains green pigment called chlorophyll
- chlorophyll is essential for photosynthesis
16
Q
Vacuoles
A
- fluid-filled space enclosed by a partially permeable membrane
- stores substances within cell
- plants cells have 1 large vacuole containing cell sap
- animal cells have many small temporary vacuoles that contain water and food substances
17
Q
Differnciation
A
- process by which a cell becomes specialised for specific function
18
Q
How a rbc is adapted to its function
A
- contain haemoglobin which bind reversibly with oxygen to form oxyhemoglobin and transports it all over the body
- has a circular biconcave shape which increases surface area-to-volume ratio, increasing rate of diffusion
- lacks a nucleus, enabling rbc to store more haemoglobin to transport more oxygen
- is flexible and therefore can squeeze through capillaries easily
19
Q
How muscle cell is adapted to its function
A
- is elongated and cylindrical in shape, containing many nuclei and mitochondria
- has mitochondria to provide energy for contraction of muscle cells
20
Q
How root hair cell is adapted to its function
A
- has a long and narrow root hair to increase surface area-to-volume ratio to absorb water and mineral salts at a higher rate
21
Q
When to use surface area to volume ratio
A
- Red blood cells
- Root hair cells
- Emulsification
- Dialysis Machine Tubing
