Bio Practice Test Flashcards
Characteristics of Life
- Growth and development
- Acquire energy - including nutrients and gas exchange
- Reproduction
- Respond to stimuli
- Homeostasis
- Order and organization
- Adaptation
Question 2 based on cell theory
CELL THEORY –
- All living things are made of one or more cells
- A cell is the simplest unit that can carry out life processes
- All cells must come from other cells
Are elephant cells larger than mouse cells?
??Larger mammals don’t typicall have bigger cells, they just have more of them.
add more from your notes
What are the two major phases of the cell cycle?
The cell cycle is divided into two major phases: interphase and mitosis (or the mitotic (M) phase).
Interphase is the longest part of the cell cycle. This is when the cell grows and copies its DNA before moving into mitosis. During mitosis, chromosomes will align, separate, and move into new daughter cells.
The prefix inter- means between, so interphase takes place between one mitotic (M) phase and the next.
What happens during Interphase and what are the three parts
Interphase is the longest phase of the cell cycle. During this phase the cell grows to its maximum size, performs its normal cellular functions, replicates its DNA, and prepares for cell division. This stage is divided into three parts: G1 phase, G2 phase and S phase.
Interphase
What happens during G1 phase?
The cell grows larger and organelles are duplicated and starts replicating centrosomes.
Cells in this stage synthesise proteins and increase in size.
Cells can remain in this stage for a long time.
Interphase
What happens during S phase
Is the stage during which DNA replication occurs.
The cell makes an identical copy of each of its chromosomes.
Chromosomes are found inside the nucleus of the cell and consist of long strands of DNA that contain the genetic information of the cell.
Interphase
What happens during G2 phase?
Occurs after the DNA had been duplicated in S phase.
During this phase the cell may continue to grow and undergo normal cellular functions.
Towards the end of this phase the cell will start to replicate its organelles and reorganize its content in preparation for mitosis.
Centrosome replication is completed
What happens during Mitosis (Mitotic Phase)?
The mitotic phase (M phase) is composed of two tightly coupled processes: mitosis and cytokinesis.
During mitosis the chromosomes in the cell nucleus separate into two identical sets in two nuclei.
This is followed by cytokinesis in which the cytoplasm, organelles and cell membrane split into two cells containing roughly equal shares of these cellular components.
What are the 4 phases of Mitosis in order?
- Prophase
- Metaphase
- Anaphase
- Telophase
What occurs during Prophase?
During prophase, the first phase of mitosis, the duplicated chromosome condenses and becomes visible.
The centrioles move to opposite sides of nucleus and help organize the spindle.
The spindle forms and DNA strands attach at a point called their centromere.
The nucleolus disappears and nuclear envelope breaks down.
What occurs during Metaphase?
During metaphase, chromosomes line up on the equator of the cell or metaphase plate.
The chromosomes appear in a straight line across the middle of the cell. Each chromosome is attached to the spindle fibres by its centromere.
Additional Study image of Metaphase
What occurs during Anaphase?
During anaphase the chromatids are pulled to opposite poles of the cell by the shortening of the spindle fibres.
The chromatids are now called daughter chromosomes.
Additional study image for Anaphase
What occurs during Telophase?
During telophase, a nuclear membrane reforms around the daughter chromosomes that have gathered at each of the poles.
The daughter chromosomes uncoil to form chromatin once again. The nuclear membrane reforms.
What occurs during Cytokinesis?
The cytoplasm then divides during a process called cytokinesis.
Cytokinesis is not a stage of mitosis but the process of the cytoplasm splitting into two.
In an animal cell the cell membrane constricts. This invagination or in-folding of the cytoplasm divides the cell in two.
In a plant cell a cross wall is formed by the cell plate dividing the cytoplasm in two.
Additional study image Cytokinesis
During which phase do the chromosomes become visible?
A. Telophase
B. Anaphase
C. Prophase
D. Interphase
C - Prophase
During which phase does the spindle form?
A. Telophase
B. Cytokinesis
C. Prophase
D. Interphase
C - Prophase
In What process does the cell reproduce its organelles?
A. Mitosis
B. G1 Phase
C. Cytokinesis
D. Spindle formation
B - G1 Phase
G1 phase: Occurs just after the two daughter cells have split and the cells have only one copy of their DNA. Cells in this stage synthesise proteins and increase in size. Cells can remain in this stage for a long time.
A. Prophase
B. Metaphase
C. Cytokinesis
D. Anaphase
With the aid of labelled diagrams explain how prophase and interphase are similar and different.
When will a cell undergo mitosis
A. Before the DNA has been replicated
B. When there is limited space
C. When a protein signals it is time
D. When there are limited resources
C - When a protein signals it is time
CYTOPLASM
WHAT IS IT:
Jelly-like substance that fills the cell
FUNCTION:
Holds organelles in place, allows cell reaction to occur
CELL MEMBRANE
WHAT IS IT:
Semi-permeable, double membrane
FUNCTION:
Determines what enters and leaves the cell
NUCLEUS
WHAT IS IT:
Control center of the cell
FUNCTION:
Controls all cell activities and contains DNA/chromosones
MITOCHONDRIA
WHAT IS IT:
Powerhouse, site of energy production from sugars by cellular respiration.
FUNCTION:
Makes oxygen available to the cell - there are more mitochondria in more active cells
ER - ENDOPLASMIC RETICULUM
WHAT IS IT:
Network of 3D tubes and pockets that run through the cytoplasm from the nuclear membrane to the cell membrane
FUNCTION:
Used for transport
VACUOLES
FUNCTION:
Many functions depending on the cell - storage of food/wastes, or water, removing waste from the cell, or maintaining fluid pressure
VACUOLE # IN ANIMAL CELLS
Many small vacuoles (not visible)
VACUOLE # IN PLANT CELLS
1 large vacuole
GOLGI COMPLEX
FUNCTION:
Collect and process materials to be removed from the cell
CELL WALL
WHAT IS IT:
Wall found only in plant cells just outside the cell membrane
FUNCTION:
Provides support and protection
CHLOROPLASTS
WHAT IS IT:
Found only in plant cells, contains chlorophyl
FUNCTION:
Makes them and the plants green and allows photosynthesis to take place
RIBOSOMES
WHAT IS IT:
Site of protein synthesis, exist free in the cytoplasm as well as attached to the outer surface of the rough ER
CENTRIOLES
WHAT IS IT:
Only in animal cells
FUNCTION:
Create and control spindle fibers in cell division
NUCLEOLUS
WHAT IS IT:
Area inside the nucleus where ribosomes are made
LYSOSOMES
WHAT IS IT:
The garbage can of the cell
FUNCTION:
Contains digestive enzymes to help eliminate waste
