Cells Flashcards
What is the cell?
The smallest structural and functional unit in a living being
What are the 2 types of cells?
Prokaryotic
Eukaryotic
What is the key difference between eukaryotic and prokaryotic cells?
Prokaryotic cells don’t have a nucleus, while eukaryotic cells do
What’s an example of a prokaryotic cell?
Bacteria
What are examples of eukaryotic cells?
(4)
Protists
Fungi
Animals
Plants
What are viruses?
Acellular parasites that can’t reproduce on their own,so they need a host
What do viruses need to reproduce?
A host cell
What type of genome do viruses have?
A viral genome (DNA or RNA) encapsulated by proteins
What are the 2 distinct parts of a eukaryotic cell?
Cytoplasm
Nucleus
What are the cell components of a prototypic human cell? (NOT PROKARYOTIC)
(11)
Cell membrane
Nucleus
Rough endoplasmic reticulum (RER)
Smooth endoplasmic reticulum (SER)
Nucleolus
Ribosomes
Lysosome
Mitochondria
Golgi apparatus
Cytoplasm
What does the cell membrane do?
It forms the outer boundary of the cell which separates the inside of the cell from the outside. Therefore,it controls the movement of substances in and out of the cell
What does the nucleus do?
(2)
It contains the cell’s DNA in the form of chromosomes.
It allows for protein synthesis to happen through transcription and translation
What are the 2 types of endoplasmic reticulum?
Rough
Smooth
What does the rough endoplasmic reticulum (RER) do?
It’s studded with ribosomes and packages and processes proteins in order to create and modify proteins
What does the smooth endoplasmic reticulum (SER) do?
(3)
It synthesises and processes lipids
It plays a role in detoxification
It plays a role in calcium storage
What does the nucleus do?
(2)
It stores the main material of the cell
It’s the control centre of the cell
What is the nucleolus?
The core of the nucleus
What does the nucleolus do?
It contains rRNA and proteins that help to produce ribosomes
What do ribosomes do?
They create amino acids into proteins
What do lysosomes do?
(2)
They contain highly acidic fluid which breaks down bacteria and cell debris
They play an important role in the immune system’s cells
What does the mitochondria do?
It creates ATP
What does ATP stand for?
Adenosine triphosphate
What does the Golgi apparatus do?
It modifies and packages lipids and proteins produced by the ER and prepared them for transport
What does the cytoplasm do?
It’s a jelly like substance that fills the cell and provides an environment for many processes
What is the importance of the cell cycle?
(3)
Reproduce
Growth
Renewal of tissue
What happens in the cell cycle?
A cell divides into 2 new cells
What are the stages of the cell cycle?
(4)
Gap phase 1 (G1)
Synthesis (S)
Gap phase 2 (G2)
Mitosis
What are the stages of interphase?
(3)
Gap phase 1 (G1)
Synthesis (S)
Gap phase 2 (G2)
Which parts of the cell cycle contain cell growth?
(2)
Gap phase 1 (G1)
Gap phase 2 (G2)
Which part of the cell cycle includes DNA synthesis?
Synthesis (S)
What are the stages of mitosis?
(6)
Prophase
Prometaphase
Metaphase
Anaphase
Telophase
Cytokinesis
What happens during prophase of mitosis?
(3)
Chromosomes condense and become visible
Spindle fibres form
Nuclear envelope breaks down
What happened during prometaphase of mitosis?
(3)
Chromosomes continue to condense
Kinetochores appear at the centromeres
Mitosis spindle microtubules attach to kinetchores
What happens during metaphase of mitosis?
(2)
Chromosomes line up at the metaphase plate
Each sister chromatid attaches to a spindle fibre from the opposite pole
What happens during anaphase of mitosis?
(2)
Centromeres split in 2
Sister chromatids (which are now called chromosomes) are pulled to opposite poles
What happens during telophase in mitosis?
(4)
Chromosomes arrive at opposite poles
Chromosomes start to decondense
Nuclear envelope surrounds each set of chromosomes
The spindle fibres continue to push the poles apart
What happens during cytokinesis in the mitosis of animal cells?
A cleavage furrow separates the daughter cells
What happens during cytokinesis in the mitosis of animal cells?
A cleavage furrow separates the daughter cells
What happens during cytokinesis in the mitosis of plant cells?
A cell plate separates the daughter cells
What are checkpoints in the cell cycle?
They’re stages where the cell decides whether or not to progress through the cell cycle
Why are checkpoints useful during the cell cycle?
They regulate the cell
When do checkpoints occur during the cell cycle?
Why?
(4)
After G1 to check for DNA damage
After G2 to check for damaged or unduplicated DNA
After G2 to check for unduplicated centromeres
After mitosis to check that the chromosome attached to the mitotic spindle
As well as checkpoints throughout the cell cycle, what is also found near the end of G1?
A restriction point
What is a restriction point used for near the end of G1 in the cell cycle?
(2)
To check for cell size
To check for favourable environmental conditions7
How many hours does G1 last in a cultured cell?
10hrs
How many hours does synthesis last in a cultured cell?
7.5hrs
How many hours does G2 last in a cultured cell?
3.5hrs
How many hours does mitosis last in a cultured cell?
1hr
How do we remember the stages of mitosis?
PPMAT CYTOKINESIS
What is meiosis?
A type of cell division that results in 4 daughter cells with half the number of chromosomes as the parent cell and gametes
What are the 2 types of gametes?
Ova (egg)
Sperm
How are chromosomes organised?
Into 2 linear units
What are chromosomes formed by?
(2)
DNA and highly condensed proteins
How many chromosomes are found in the DNA of a normal human cell?
46
How many autosomes are found in the DNA of a normal human cell?
44
How many sex chromosomes are found in the DNA of a normal human cell?
2
Which sex chromosomes are male?
XY
Which sex chromosomes are female?
XX
What are found on chromosomes?
(5)
Telomere
Centromere
2 sister chromatids
Kinetochore
Spindle microtubules
Why are telomeres useful on chromosomes?
They prevent the chromosome from degrading
Why are centromeres useful on chromosomes?
They allow the chromosomes to divide
Why are kinetochores useful on chromosomes?
They support the distribution of the mother’s genome to the daughter’s cells
Where are the telomeres found on chromosomes?
At the top of each chromatid
What is a nucleotide?
A structure made up of a 5 carbon sugar, a phosphate group and a nitrogenous base
What is the sugar in a DNA molecule?
Deoxyribose
What can the nitrogenous base in a DNA nucleotide be?
(4)
Adenine
Thymine
Cytosine
Guanine
How can we remember the nitrogenous bases and which they pair to?
Apple tree
(Adenine thymine)
Car garage
(Cytosine guanine)
What is a karyotype?
A person’s complete set of chromosomes
What is a karyotype used for?
(3)
It’s used to check for abnormalities in the chromosome number or structure
It’s useful in studying human evolution
It’s useful in understanding some pathologies
How much of everyone’s karyotype is identical?
90%
When does fertilisation happen?
When a sperm cell successfully meets an egg cell in the fallopian tube
What is a sperm cell also known as?
A spermatozoon
What is an egg cell also known as?
An ova
What is embryogenesis?
The process where the embryo forms and develops
When is the embryonic period?
First 10 weeks of development
When is the fetal period?
Weeks 11-40
What are the 4 types of body tissues?
Nervous tissue
Epithelial tissue
Muscle tissue
Connective tissue
What does nervous tissue contain?
(3)
Brain
Spinal cord
Nerves
What does epithelial tissue contain?
(2)
Lining of gastrointestinal tract (GI), organs and other hollow organs
Skin surface (epidermis)
What does muscle tissue contain?
(3)
Cardiac muscle
Smooth muscle
Skeletal muscle
What does connective tissue contain?
(3)
Fat and other soft padding tissue
Bone
Tendon
