exam revision Flashcards
(113 cards)
1
Q
What does SA:V stand for?
A
Surface area to volume ratio
2
Q
Why is SA:V important for cells?
A
It is crucial for the transport of substances in and out of the cell
3
Q
What happens to the volume and surface area as an object grows in size?
A
Volume increases at a much faster rate than surface area
4
Q
What is required for a cell to sustain life?
A
Efficient transport of substances like glucose, ions, oxygen, carbon dioxide
5
Q
What is a characteristic of an efficient cell in terms of SA:V?
A
It needs to have a LARGE surface area to volume ratio
6
Q
What does a small SA:V ratio indicate?
A
Both numbers are very close together
7
Q
What does a large difference in SA:V ratio signify?
A
It indicates a more efficient cell
8
Q
Fill in the blank: As an object gets fatter, the time taken for chemicals to transport through the cell _______.
A
slows down
9
Q
What is the function of the plasma membrane?
A
Controls the passage of materials into and out of a cell
10
Q
What is the structure of the plasma membrane?
A
Bilayer of phospholipids
11
Q
What does semi-permeable mean in the context of the plasma membrane?
A
Only some materials may enter/exit
12
Q
Which types of molecules can easily pass through the plasma membrane?
A
Small, uncharged molecules
13
Q
Which types of molecules have difficulty or are unable to pass through the plasma membrane?
A
Large molecules; Ions
14
Q
What are the two main components of a phospholipid head?
A
- Phosphate Group
- Glycerol
15
Q
What are the components of the nonpolar tails of phospholipids?
A
Two chains of fatty acids
16
Q
Define a polar molecule
A
Molecule where one area has a positive charge, while another area has a negative charge
17
Q
What does hydrophilic mean?
A
Water loving
18
Q
What does hydrophobic mean?
A
Water fearing
19
Q
What is the arrangement of phospholipids in the plasma membrane?
A
Outside: Polar heads; Inside: Nonpolar Tails
20
Q
What is the Fluid Mosaic Model?
A
Describes the plasma membrane structure as a mosaic of various components
21
Q
What role does cholesterol play in the plasma membrane?
A
Prevents phospholipids from separating too far, providing flexibility
22
Q
What is the function of carbohydrates in the plasma membrane?
A
Identification/recognition
23
Q
How is blood type determined?
A
By the carbohydrates on our cells
24
Q
What is a protein channel?
A
Allows certain objects to pass through the plasma membrane
25
What is the role of the cytoskeleton in the cell?
Provides internal support and a pathway for molecule transport
26
Fill in the blank: The head of a phospholipid is made up of a phosphate group and _______.
[glycerol]
27
Fill in the blank: The tails of phospholipids consist of _______ chains of fatty acids.
Two
28
True or False: The polar heads of phospholipids are oriented towards the interior of the membrane.
False
29
What are the three parts of a phospholipid?
* Polar Head
* Nonpolar Tails
* Fatty Acids
30
Describe the role of cholesterol in the plasma membrane.
Prevents phospholipids from separating too far, providing flexibility
31
Describe the role of protein channels in the plasma membrane.
Allows certain objects to pass through the membrane
32
What is active transport?
Molecules move from a LOW to a HIGH concentration against the concentration gradient
33
What is ATP?
Adenosine Triphosphate
34
What role does ATP play in active transport?
Opens/closes protein channels to move molecules against the concentration gradient
35
What is diffusion?
Movement of molecules from an area of higher concentration to an area of lower concentration
36
What is facilitated diffusion?
Process where molecules pass through a membrane via protein channels without energy use
37
What is the function of the contractile vacuole in Paramecium?
Pumps out excess water to prevent the cell from bursting
38
What is endocytosis?
Process in which the plasma membrane takes in substances
39
What is phagocytosis?
When a cell engulfs a solid particle
40
What is pinocytosis?
When a cell engulfs a liquid particle
41
What is exocytosis?
Process when substances are expelled from the cell
42
What role do vesicles play in exocytosis?
Carry and release objects through the plasma membrane
43
Fill in the blank: During active transport, molecules move ______ the concentration gradient.
against
44
How are endocytosis and exocytosis similar?
Both involve the movement of substances in and out of the cell
45
How are endocytosis and exocytosis different?
Endocytosis takes substances into the cell, while exocytosis expels substances out
46
Which molecule powers active transport?
ATP
47
Which organelle fuses with the cell membrane during exocytosis?
Vesicle
48
Once inside a cell, what kills bacteria that have been swallowed by endocytosis?
Digestive Enzymes
49
What is passive transport?
Cell spends no energy (ATP) to move molecules. Molecules move from a high to low concentration
Down their concentration gradient
50
What are the different types of passive transport?
Types of Passive Transport:
Diffusion
Osmosis
Facilitated diffusion
51
What is osmosis?
Diffusion of water from a high to low concentration
Distilled water
100% pure H2O (no solutes)
Hypotonic environment
52
What is a hypotonic solution?
Solution with a lower concentration of solutes compared to the cell
53
What is hypertonic solution?
Solution with a greater concentration of solutes
54
Mitosis
Part of cell division in eukaryotic cells in which the nucleus divides eventually producing 2 daughter cells which are genetically identical to the parent cell
54
What is an isotonic solution?
Having an equal solute concentration to that of the cell.
55
Cytokinesis
Part of cell division in which the cytoplasm is divided between the 2 new daughter cells
56
Chromatid
One of two identical parts or arms of a chromosome
57
Centromere
Region of the chromosome where the 2 sister chromatids are held together and which is the attachment site of the spindle fibers during cell division
58
Cell Cycle
Series of events including interphase, mitosis, and cytokinesis that cells go through as they grow and develop.
59
Interphase
Phase of the cell cycle in between divisions in which cells spend most of their time growing and carrying out their cellular functions in the body
60
Prophase
First and longest phase of mitosis during which chromosomes become visible, centrioles appear and move to opposite poles, and the nuclear membrane and nucleolus disappear
61
Metaphase
(MIDDLE) 2nd phase of mitosis during which the chromosomes line up along the center of the cell
62
Anaphase
(APART) third phase of mitosis in which the chromsomes break at the centromeres, and the sister chromatids move to opposite poles and ends of the cell
63
Telophase
(TWO) 4th and last phase of mitosis during which TWO nuclei are visible; the chromosomes spread out as chromatin, the nuclear membrane and nucleolus return, and mitotic spindle and centrioles disappear
64
Homologous Chromosome
A pair of morphologically similar chromosomes that are the same size and the same shape and carry genes for the same traits
65
Cell Wall
This is found outside the cell membrane. Its function is to provide support and protection.
66
Chromosomes
DNA scrunched up in a dividing cell
67
Chromatin
DNA spread out in non-dividing cells
68
Binary Fission
Cell division in PROKARYOTES; type of asexual reproduction in which an organism replicates its DNA and divides in half, producing 2 identical daughter cells
69
Prokaryotes
An organism (including all bacteria) whose cells DO NOT have a nucleus or organelles surrounded by membranes
70
Eukaryotes
An organism (including all plants & animals) whose cells contain a nucleus and organelles surrounded by membranes
71
Internal Regulators
Proteins that respond to events inside the cell; allow cell cycle to proceed only if certain processes have happened
72
External Regulators
Proteins that respond to events outside the cell; signals tell cell to speed up or slow down the cell cycle
73
Carcinogens
Are substance that can damage DNA and cause cancer.
74
Centrioles
Log-like structures that appear near the nucleus during cell division in an animal cell and move to opposite poles to pull the chromosomes apart
75
Spindle
Fan-like structure made of microtubules that helps separate the chromosomes during mitosis
76
Cyclin
one of a family of proteins that regulate the cell cycle in eukaryotic cells
77
Cancer
disorder in which some of the body's own cells lose the ability to control growth
78
Centrosome
Region in which the centrioles lie that helps organize the spindle fibers during cell division
79
Somatic
These are body cells (everything in your body except sperm & egg)
80
What is MRS GREND
Movement, Respiration, Sensitivity to Stimuli, Growth, Reproduction, Excretion of Waste, Nutrition, and DNA
81
The Cell Theory
All living things are made of one or more cells.
Cells are the basic unit of structure and function in living things.
All cells come from pre-existing cells.
82
Prokaryotic Cell
Smaller, simpler cell
Have a cell membrane, and cilia/flagella
Lack a nucleus and most other organelles – only contain circular DNA, Ribosomes, cell wall and cytosol
Examples include: Bacteria & Archaea
83
Eukaryotic Cell
Eukaryotes are more complex cells – evolved from prokaryotic ancestor
Have a nucleus surrounded by its own membrane and other membrane-bound organelles.
Examples include: Protists (i.e. Amoeba), Fungi, Plants & Animals
84
Plant Cells
Are part of a multi-cellular organism
Have nucleus and organelles
Have a cell wall and a cell membrane
Have a structured shape
Autotrophic:
85
Animal Cells
Are a part of a multi-cellular organism
Have nucleus and organelles
Do not have cell walls (only cell membrane)
Do not have a structured shape
Heterotrophic:
86
Nucleus
Holds the DNA of eukaryotes
Made up of nucleolus (contains ribosomal RNA) and nuclear envelope (membrane), which ensures the protection of the DNA
Contains MOST of the cell’s DNA
The function of the nucleus is to direct the cell’s activities
87
Ribosomes
Involved in and site of protein synthesis
Not membrane bound (also found in prokaryotic cells)
Can be found free in the cytoplasm, or can be associated with an endoplasmic reticulum
87
Cytoplasm
The term used to describe the internal environment of the cell (includes the Cytosol and organelles)
Cytosol is a watery, or jelly-like, solution that contains dissolved substances and enzymes
Makes the cells bulky and 3D
88
Rough Endoplasmic Reticulum (ER)
ER with ribosomes attached to it
Connected network of membranes that manufactures & transports cell products (proteins) within the cell
Site of protein synthesis
89
Smooth Endoplasmic Reticulum
ER without ribosomes
Site of lipid and carbohydrate synthesis
Continuous with plasma and nuclear membrane
Network of membranes that manufactures & transports cell products within the cell
Parts of membrane pinch off to form vesicles which transport nutrients around cell
90
Golgi Apparatus
Connected to the ER - Products from ER travel in vesicles to the Golgi Apparatus
Stores, modifies and packages proteins (inter-cellular, or between cells) – this is called exocytosis
Packages proteins into vesicles – membranous packages
91
Vacuoles
Membrane-bound sacs in the cytoplasm that store undigested nutrients (water, sugars, minerals and proteins)
Plants have a single, large central vacuole that stores water. Animals have multiple, small vacuoles
92
Lysosomes
They are the vesicles that are pinched off from the Golgi apparatus
Their function is to contain and transport the enzymes that are used to breakdown food and foreign matter
Lysosomes have several functions:
Digest nutrients and nourish the cell
Destroy harmful bacteria
93
Cytoskeleton
The internal structure of a eukaryotic cell
Made up of microfilaments and microtubules
These microtubules allow the organelles to travel around the cytoplasm and provide a structure to prevent the cell from being “squashed”
94
Chloroplast
Found only in plant cells (Not found in animal cells)
Contain chlorophyll (green pigment)
Site of photosynthesis (converts sunlight to chemical energy)
95
Mitochondria
The site of cellular respiration – processed used in eukaryotes to create usable energy
Provide the main energy source (ATP) to the cell
The number present in a cell depends on its metabolic activity
NOT FOUND IN PROKARYOTES
96
Cell Wall
Found in prokaryotic cells, fungi and plant cells
Not found in animal cells
Made of complex carbohydrates (plant cell walls are made of cellulose
Rigid structure that lies outside the plasma membrane
Provides support to the cell and sits outside the plasma membrane
97
Plasma (Cell) Membrane
The boundary of a cell (separates internal environment from external environment)
Semi-permeable (Some things can pass through it)
Controls what dissolved substances move into and out of the cell
Formed by a phospholipid bilayer (made up of lipids and phosphate molecules
98
Centriole
Centrioles are organelles found near the nucleus in animal cells.
Centrioles exist in pairs, which replicate and then migrate to the poles of the cell when it is time for cell division
They control the separation of chromosomes during cell replication.
99
What is a specialized cell?
Specialized Cells differ in structure carry out specific functions within the body.
Nerve cells
Skeletal muscle
Epithelial cells (skin)
100
What are stem cells?
Unlike specialized cells, which have a specific form and function, stem cells are not specialized. Meaning, they have the POTENTIAL to become any kind of cell.
Stem cells are found in a few places:
Embryos (when they are about 4-5 days old)
Few reserves in adults.
101
What is cell differentiation?
The specialization of cells occurring during an organism’s development
102
Pluripotent Cells
These are the cells of the
primary germ layers: ectoderm, mesoderm and endoderm. These cells can
differentiate into many cell types. Examples include embryonic stem cells from
the inner cell mass of the embryonic blastocyst.
103
Unipotent Cells
These cells have the ability to produce only cells of their own
type, but because they can self-renew they are termed stem cells. Examples
include adult (somatic) muscle stem cells.
104
Totipotent
These cells have the potential
to give rise to all cell types. Totipotent cells include the fertilized egg and
embryonic cells of a two, four or eight-cell embryo.
105
Multipotent Cells
These cells have the ability to differentiate into a closely related
family of cells; for example, a multipotent blood stem cell can develop into a red
blood cell, a white blood cell or platelets (all specialized cells).
106
Embryonic Stem Cell
An undifferentiated cell obtained
from early embryonic tissue that
is capable of differentiating into
many cell types
107
Interphase
The cell spends most of its life here performing its specialized functions and then prepares for cell division when the time comes.
108
G1 Phase (Gap1):
The cell grows after division to reach full size (it may double in size. The cell performs its specialized functions depending on what type of cell it is.
109
G0 Phase (Gap 0):
Once organisms reach adulthood,
some of their cells will never divided again.
These cells stop progressing
through the cell cycle and go into
where they will simply continue to perform their
functions until they die.
110
S Phase (Synthesis):
The DNA is replicated creating two identical copies of each chromosome. The centriole pair also duplicates to create two pairs.
The cell prepare for mitosis by undergoing rapid growth of its cytoplasm.
The DNA is checked for replication errors that may have occurred during DNA replication in S Phase.
111
Apoptosis
Apoptosis is the process of programmed cell death. It is used during early development to eliminate unwanted cells.
