Unit 1 - Cells Flashcards
What are the postulates of cell theory? (3 points)
- all organisms are made up of one or more cells
- cells arise from pre-existing cells
- cell are the smallest units of life
What are the functions of life? (7 points)
- Metabolism
- Reproduction
- Sensitivity
- Homeostasis
- Excretion
- Nutrition
- Growth
What is the study of all aspects of a cell called? (1 pt)
Cytology
What happens when the SA:Vol ratio of the cell is low? (2 pts)
The metabolic rate of the cell will be higher than the rate of vital material and waste exchange, killing the cell.
Why do cells related to Gas/material exchange have a high SA:Vol ratio? (2 pts)
The large surface area optimises material transfer (e.g., Intestinal villi and microvilli of the alveoli)
How are specialized tissues and cell differentiation related? (2 pts)
cell differentiation allows for different cell types which, when interacting with each other, carry out unique functions (e.g., skin cells emerging into skin tissue)
What are the exceptions to cell theory?
3 pts + explanation
- Striated muscle – many nuclei along the length of a single cell/muscle fibre
- Giant algae – Large organisms containing only one nucleus
- Hyphal aseptate fungi – hyphae are not divided into cells and contain many nuclei in a single hypha
Stargardt’s disease:
Juvenile _____ degeneration (a mutation of the gene in which the ________ of the ______ in the retina are impaired, causing progressive loss of eyesight and eventual blindness.)
Stargardt’s disease:
Juvenile Macular degeneration (a mutation of the gene in which the energy transport of the photoreceptors in the retina are impaired, causing progressive loss of eyesight and eventual blindness.)
Parkinson’s disease:
Degeneration of the _______ ______ ______ caused by the death of _______ secreting cells.
Degeneration of the central nervous system caused by the death of dopamine secreting cells.
Dopamine is a ________ which transmits the signals responsible for the production of smooth and purposeful movements. the ________, therefore, causes patients to exhibit the symptoms people with ________ ________ suffer. (severe tremors, unstable posture, slow movements, etc)
Dopamine is a neurotransmitter which transmits the signals responsible for the production of sooth and purposeful movements. the absence, therefore, causes patients to exhibit the symptoms people with Parkinson’s disease suffer. (severe tremors, unstable posture, slow movements, etc)
Type I diabetes:
________ diabetes due to a malfunction of the ________ cells in the pancreas which causes a decrease in the secretion of ________.
Type I diabetes:
Juvenile diabetes due to a malfunction of the islet cells in the pancreas which causes a decrease in the secretion of insulin.
How are stem cells used to treat illnesses? (1 pt)
They are therapeutic options to replace damaged cell types which aren’t self-renewal with functioning cells.
What are stem cells? (1 pt, 2 ex)
unspecialized cells with 2 unique qualities
- self-renewal (continuous replication/division)
- Potency (can differenciate into other cells)
What are the different types of stem cells? (4 pts)
- Totipotent
- Pluripotentent
- Multipotent
- unipotent
What is a Totipotent stem cell? (1 pt, 1 ex)
A stem cell which can differenciate into any type of cell AND placental tissue e.g., Zygotes
What is a Pluripotentent stem cell? (1 pt, 1 ex)
A stem cell that can turn into any cell type e.g., embryonic stem cells
What is a Multipotent stem cell? (1 pt, 1 ex)
A stem cell that can turn into a number of closely related cells e.g., Haemapoeitic adult stem cells
What is a unipotent stem cell? (1 pt, 2 ex)
A stem cell that can’t differenciate but can self renew e.g., progenitor cells, muscle stem cells, etc.
What are the uses of stem cells? (2 pts)
- embryonic development
- therapeutic options to replace damaged cell types which aren’t self renewal
Where do you get stem cells? (3 pts)
- The patient’s own cells / tissues / donated tissues from another person
- The foetal umbilical cord (blood)
- Early-stage embryos specially created using Somatic cell nuclear transfer (SCNT)
How do cells differenciate? (1 pt)
By expressing a certain cell type-specific gene
Prokaryotic cells characteristics;
- DNA in a ____ forms without _____
- DNA free in the _____ (Nucleoid region)
- Mitochondria ____
- ___ ribosomes
- no internal _______ to form ______
- size less than __ μm
Prokaryotic cells characteristics;
- DNA in a ring forms without protein
- DNA free in the cytoplasm (Nucleoid region)
- Mitochondria absent
- 70s ribosomes
- no internal compartmentalisation to form organelles
- size less than 10 μm
Eukaryotic cells characteristics;
- DNA with proteins as _____/chromatin
- DNA _____ within a nuclear ______ (nucleus)
- Mitochondria present
- __ ribosomes
- Internal compartmentalisation _____ to _____ many types of ______
- size ___ than 10 μm
Eukaryotic cells characteristics;
- DNA with proteins as chromosomes/chromatin
- DNA enclosed within a nuclear envelope (nucleus)
- Mitochondria present
- 80s ribosomes
- Internal compartmentalisation present to form many type organelles
- size more than 10 μm
What are the similarities between Eukaryotic and prokaryotic cells? (3 pts)
- both have outside boundaries that always involves a plasma membrane
- both carry out all functions of life
- DNA is present in both
A Blastula is an early stage of ______ ______ in animals. It is produced by ______ of a fertilized ovum and consists of a spherical layer of around ______ cells surrounding a central fluid-filled cavity called the ______.
An early stage of embryonic development in animals. It is produced by cleavage of a fertilized ovum and consists of a spherical layer of around 128 cells surrounding a central fluid-filled cavity called the blastocoel.
What is an autosomal cell? (1 pt)
regular cells (non-sex cells)
what are the different types of cell division? (2 pts)
meiosis and mitosis
Mitosis:
___ phase of cell cycle. usually happens exclusively to ___ cells.
Happens during ______ repair and ______.
Where ______ and specialization occur when forming new cells.
produces identical ______ cells
Mitosis:
M phase of cell cycle, usually happens exclusively to autosomal cells.
Happens during tissue repair and growth.
Where differentiation and specialization occur when forming new cells.
produces identical daughter cells
What is the outermost part of a plant cell? (1 pts)
cell wall of cellulose
what is a gamete? (1 pt, 2 ex)
a sex cell (egg and sperm cells)
chromosomal alignment ensures mitotic fidelity by promoting ______ compaction during anaphase. During mitosis, chromosomes align at the ______ ______ to establish a metaphase plate
chromosomal alignment ensures mitotic fidelity by promoting interchromosomal compaction during anaphase. During mitosis, chromosomes align at the spindle equator to establish a metaphase plate
What is a cyclin (2 pts)
any of a group of proteins active in controlling the cell cycle and in initiating DNA synthesis.
the role of cyclins in cell division:
- Cyclins control different stages of the ______ ______
- ______ of each cyclin rise and fall in each stage, activates proteins
- The activated proteins carry out reactions that allow the cell cycle to continue
the role of cyclins in cell division:
- Cyclins control different stages of the cell cycle
- Concentrations of each cyclin rise and fall in each stage, activates proteins
- The activated proteins carry out reactions that allow the cell cycle to continue
What are the features of a prokaryotic cell? (6 pts)
- cell wall
- plasma membrane
- flagella
- pili
- ribosomes
- nucleoid region
What are the organelles of a eukaryotic cell? (9 pts)
- smooth/rough ER
- ribosomes
- lysosomes
- Golgi apparatus
- mitochondria
- nucleus
- chloroplast
- centrosomes
- vacuoles
What is the role of the cell wall in a prokaryotic cell? (2 pts)
The peptidoglycan cell wall protects and maintains the shape of the cell.
What is the role of the pili in a prokaryotic cell? (2 pts)
Attachment and joining bacterial cells in preparation for DNA transfer to one another (sexual reproduction)
What is the role of the flagella in a prokaryotic cell? (1 pts)
allows cell to move
What is the role of the nucleoid region in a prokaryotic cell? 3 pts
contains a single, long, continuous, circular thread of DNA. Involved with cell control
During ______ ______ DNA is copied, two daughter chromosomes become ______ to different regions of the ______ ______, cells divide into 2 genetically identical daughter cells
During binary fission DNA is copied, two daughter chromosomes become attached to different regions of the plasma membrane, cells divide into 2 genetically identical daughter cells
Describe the role of the endoplasmic reticulum (1 pts)
Transports materials between organelles
Describe the role of the ribosomes (1 pt)
Site of polypeptide synthesis (DNA translation)
Describe the role of the lysosomes (1 pt)
Breakdown / hydrolysis of macromolecules
Describe the role of the Golgi apparatus (2 pts)
Involved in the sorting, storing, modification and export of secretory products
Describe the role of the mitochondria (1 pts)
Carries out the reactions of the Krebs cycle/aerobic respiration
Describe the role of the chloroplast (2 pts)
Site of photosynthesis – manufactured organic molecules are stored in various plastids
Describe the role of the centrosomes (2 pts)
Radiating microtubules form spindle fibres and contribute to cell division (mitosis / meiosis)
Describe the role of the vacuoles (1 pt)
Maintains hydrostatic pressure (animal cells may have small, temporary vacuoles)
What is a thylakoid (2 pts)
Flattened membrane sacks with components necessary for the absorption of light.
What is a granum (plural grana) (1 pt)
a stack of numerous thylakoids
What is the extracellular matrix of most animal cells composed of? (3 pts)
collagen fibres and glycoproteins that form fibre like structures that anchor the matrix to the plasma membrane.
What are universal organelles? (2 pts, 3 ex)
Organelles present in every cell, prokaryote and eukaryote. (ribosomes, cytoskeleton and plasma membrane)
Describe the role of the cytoskeleton (2 pts)
Provides internal structure and mediates intracellular transport (less developed in prokaryotes)
Describe the role of the plasma membrane (2 pts)
Semi-permeable and selective barrier surrounding the cell
Describe the role of the Peroxisome (2 pts)
Catalyses breakdown of toxic substances (e.g. H2O2) and other metabolites
What does the smooth ER transport? (1 pts)
Lipids
What does the rough ER transport? (1 pt)
Proteins
What can be found in the cell membrane? (3 pts)
- Glycoproteins
- Intergral/inter-membrane proteins
- Cholesterol
What is the role of cholesterol in the cell membrane? (3 pts)
Helps regulate membrane fluidity. Important for membrane stability. Allows membrane to function effectively at a wider range of temperatures.
What is the role of glycoproteins in the cell membrane? (2 pts)
Plays a role in the recognition of like cells and are involved in immune responses
What are the functions of the proteins in the cell membrane? (5 pts)
-sites for hormone-binding
-enzymatic action
-cell adhesion
-cell-to-cell communication
-channels for passive transport
pumps for active transport
What is the sequence for mitosis? (4 pts)
Prophase, Metaphase, Anaphase, Telophase
What is an amphipathic molecule? (2 pts, 2 ex)
An amphipathic molecule is a molecule that has both polar and non-polar parts e.g., phospholipids, cholesterol
What is an amphipathic molecule?
An amphipathic molecule is a molecule that has both polar and non-polar parts e.g., phospholipids, cholesterol
How do you calculate mitotic index?
The mitotic index is the number of cells undergoing mitosis divided by the total number of cells
how does the mitotic index can be used in the diagnosis of cancer
Mitotic index is a measure for how fast the cells are dividing (also known as proliferation) A high mitotic index means that the cells might be cancerous
Define the term “cell differentiation”
the process by which a cell changes from an undifferentiated cell / a stem cell to a specialised cell by expressing some of its genes and not others
what term is used to describe the fact that multicellular organisms are more than just the sum of their parts?
Emergent properties
What is an organism’s entire set of genes called?
a genome
What is an example of an ethical issue with using stem cells?
if taken from an embryo, it is a human life with human rights. counter: early embryos have yet to develop essential feature of human life, no nervous system therefore no pain.
Define the term resolution in magnification
the level of detail within an image shown by how distinguishable two separate points are.
What are the types of electron microscopes?
- Scanning electron microscope (SEM)
- Transmission electron microscope (TEM)
Which electron microscope can be used to view 3D images of surface structures?
Scanning electron microscope (SEM)
Describe cell ultrastructure
The detailed, compartmentalised structures inside cells
Which eukaryotic organelles have double membranes?
- Nucleus
- Mitochondrion
- Chloroplast
What happens to the cell membrane as cholesterol levels increase?
fluidity and permeability will be reduced
What type of solution should donor organs be placed in?
Isotonic
What are the types of bulk transport?
Endocytosis & Exocytosis
Explain the endosymbiotic theory
the theory that Eukaryotes evolved from prokaryotes and the mitochondria and chloroplasts were once separate living organisms
Proof of endosymbiotic theory
-mitochondria and plastids contain DNA separate from the cell nucleus
-they have their own protein biosynthesis machinery
they have 70s ribosomes like bacteria
What are sister chromatids?
2 parts of a duplicated chromosome joined by the centromere
What are the three phases of interphase?
G1, S phase and G2
In which phase of cell division does DNA replication take place?
S phase of the interphase
What is oncogenesis?
A process that starts the formation of tumours due to the mutation of the oncogenes
What is metastasis?
The spreading of cells to form tumours in different arts of the body
Where does mitosis occur the most frequently?
Developing embryos
When is mitosis required?
During GATE
- Growth
- Asexual reproduction
- Tissue repair
- Embryonic development)
Which part of the cell cycle DOESN’T involve cell division?
Interphase
Describe G1 phase
- volume of cytoplasm increases
- organelles are produced
- protein is synthesised
Describe the S (synthesis) phase
DNA is replicated
Describe G2 phase
- volume of cytoplasm increases
- organelles are produced
- protein is synthesised
Describe G2 phase
- volume of cytoplasm increases
- organelles are produced
- protein is synthesised
During which stage of the cell cycle does the cell carry out it’s normal function?
Interphase
What is a centromere?
The part of a chromosome that links sister chromatids
______ ______ are duplicated chromosomes attached by a ______. When they separate after anaphase, they are referred to as ________.
Sister chromatids are duplicated chromosomes attached by a centromere. When they separate after anaphase, they are referred to as chromosomes
Prophase:
DNA ______ and ______ condenses becoming sister chromatids, centrosomes move to the opposite poles of cell and ______ ______ form between them, the nuclear membrane breaks down and disappears
Prophase:
DNA supercoils and chromatin condenses becoming sister chromatids, centrosomes move to the opposite poles of cell and spindle fibres form between them, the nuclear membrane breaks down and disappears
Metaphase:
spindle fibres from each centrosome attach to ________ of each pair of sister chromatids, ________ of microtubule spindle fibres cause ______ ______ to line up along the centre of cell.
spindle fibres from each centrosome attach to centrosomere of each pair of sister chromatids, contraction of microtubule spindle fibres cause sister chromatids to line up along centre of cell.
Anaphase
continued contraction of ________ ________ fibres causes separation of sister chromatids (Separate chromatids are referred to as ________). Chromosomes move to the opposite poles of the cell.
Anaphase
continued contraction of microtubule spindle fibres causes separation of sister chromatids (Separate chromatids are referred to as chromosomes). Chromosomes move to the opposite poles of the cell.
Telophase
chromosomes ________ and de-condense into ________, spindle fibres disappear, new ________ ________ reform around each chromosome set
Telophase
chromosomes uncoil and de-condense into chromatin, spindle fibres disappear, new nuclear membranes reform around each chromosome set
What is cytokinesis?
the division of the cell into 2 daughter cells. happens concurrently with telophase.
What are mutagens?
Agents that cause gene mutations e.g., carcinogens, high energy radiation, short-wave ultraviolet light, viruses
Factors that increase probability of tumour development
Mutagens, more cell number = higher mutation chance, long lifespan = greater chance of mutation
What is a primary tumour?
a malignant tumor growing at the site where abnormal growth first occurred
What is the role of the plasma membrane in a prokaryotic cell?
The plasma membrane controls the movement of materials in and out of the cell.
what does it mean when a tumour is malignant?
it invades normal tissue or to recur after removal (is cancerous)
What is chromatin?
Chromatin is a substance within a chromosome consisting of DNA and protein.
what is the structure of endoplasmic reticulum
A membrane network that may be bare (smooth ER) or studded with ribosomes (rough ER)
what is the structure of ribosomes
Two subunits made of RNA and protein; larger in eukaryotes (80S) than prokaryotes (70S)
what is the structure of Lysosomes
Membranous sacs filled with hydrolytic enzymes
what is the structure of golgi apparatus
An assembly of vesicles and folded membranes located near the cell membrane
what is the structure of mitochondria
Double membrane structure, inner membrane highly folded into internal cristae
what is the structure of chroloroplast
Double membrane structure with internal stacks of membranous discs (thylakoids)
what is the structure of centrosomes
Microtubule organising centre (contains paired centrioles in animal cells but not plant cells)
what is the structure of vacuoles
Fluid-filled internal cavity surrounded by a membrane (tonoplast)
what is the structure of cytoskeleton
A filamentous scaffolding within the cytoplasm (fluid portion is cytosol)
what is the structure of plasma membrane
Phospholipid bilayer embedded with proteins (not an organelle but a vital structure)
what is the structure of peroxisome
Membranous sac containing a variety of catabolic enzymes
