Unit 1 All Together + General Ques

Bacterial cells are prokaryotic, in comparison to a typical eukaryotic cell, bacterial cells would;

Be smaller

The production of ATP

In eukaryotes, mitochondria are the organelles primarily involved in

Secrete a lot of protein

You would expect a cell with an extensive Golgi apparatus to

nucleus, rough endoplasmic reticulum, golgi body, vesicle

What is the correct order in which organelles function to make and secrete an enzyme?

Partially permeable

Some substances can move through the plasma membrane. The membrane is said to be

Diffusion

Carbon dioxide can also move freely through the plasma membrane by the process of

Dna replication, mitosis, cytokinesis

In cell replication, the correct order of events is

Endosymbiosis

A term used to describe two organisms living together with one inside the other

Membrane bound

Structures such as organelles found in eukaryotic cells, which are enclosed by a lipid bilayer

Organelle

A sub-cellular (contained within a cell) structure that has one or more specific jobs to preform in the cell

2lw+2lh+2hw

Formula for surface area

LxWxH

Formula for volume

Single Membrane

An organelle with only one membrane communicate with external medium eg. Vacuole, lysosome, golgi apparatus & endoplasmic reticulum

Double Membrane

Organelles with two membranes have cytoplasm in the inner compartment eg. Nucleus, mitochondria & chloroplast

Prokaryotic cells

Cells lacking a nucleus and membrane-bound organelles, typically smaller and simpler than eukaryotic cells. Examples include bacteria and archaea, produces asexually

Eukaryotic cells

Cells with a nucleus and membrane-bound organelles, generally larger and more complex than prokaryotic cells. Examples include animal and plant cells, produces sexually

Cytoplasm

The gel-like substance inside the cell membrane that contains organelles and is the site of many metabolic processes

Cytosol

The fluid component of the cytoplasm, excluding organelles and other solid structures, where many cellular processes occur

Chloroplast

A green organelle in plant cells that conducts photosynthesis by converting sunlight (photosynthesis) into chemical energy in the form of glucose

Mitochondria

Organelles known as the powerhouses of the cell, responsible for producing ATP through cellular respiration

Cellular Respiration

The biochemical process by which cells convert glucose and oxygen into energy (ATP), releasing carbon dioxide and water as byproducts, C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + ATP

Nucleus

The organelle that houses the cell's genetic material (DNA) and coordinates activities such as growth, metabolism, and reproduction

Rough endoplasmic reticulum

A type of endoplasmic reticulum covered with ribosomes, involved in protein synthesis and processing

Smooth endoplasmic reticulum

A type of endoplasmic reticulum that is not covered with ribosomes, involved in lipid synthesis and detoxification

Golgi apparatus

An organelle that modifies, sorts, and packages proteins and lipids for secretion or delivery to other organelles

Protein

A large, complex molecule made up of amino acids, playing vital roles in the structure, function, and regulation of the body's tissues and organ

Centrioles

Cylindrical structures involved in cell division and the formation of spindle fibers, help ensure the correct chromosomes are available to each daughter cell upon division

Peroxism/peroxisome

Break down fatty acids to be used for forming membranes & as a fuel for respiration, looks like half a coconut

Equilibrium

When equal numbers of a specific molecule are on either side of the plasma membrane

Plasma membrane

A biological membrane that separates and protects the interior of a cell from the external environment, regulating what enters and exits the cell

Fluid

Describes the liquid nature of the membrane, it can move freely because of the cholesterol

Mosaic

Describes the composition of the membrane being made up of thousands of lipids and proteins

Phosphate head

(A) The hydrophilic ‘water loving’ part of a phospholipid that interacts with water, making it essential for forming the plasma membrane

Fatty acid tail

(A) The hydrophobic ‘water fearing’ part of a phospholipid that repels water and helps form the lipid bilayer of the plasma membrane

Glycolipid

(B) A lipid with a carbohydrate attached, contributing to cell recognition and the maintenance of the cell membrane, acts as receptors for messenger molecules, LIPID OF THE PM

Glycoprotein

(C) A protein with a carbohydrate group attached, playing a key role in cell recognition, signaling, and maintaining the structure of the cell membrane, PROTEIN OF THE PM

Cholesterol

(E) A type of lipid that is found in the cell membrane, playing a crucial role in maintaining membrane fluidity and stability, steroid molecule

Lipid

Hydrophobic molecules for energy storage, membrane structure, and signalling

Peripheral protein

(F) Offers support, communication, enzymes & molecule transfer in the cell

Integral protein

(G) Embedded with the bilayer, involved in transporting large molecules across the membrane

Bilayer

(H) The two layers in between the plasma membrane

Simple diffusion, facilitated diffusion & osmosis

What are the three main ways for passive transport?

Simple diffusion

Passive movement of substances across the plasma membrane - movement of small or lipophilic molecules without the need for energy or transport proteins

Facilitated diffusion

Molecules diffuse across the plasma membrane with assistance from membrane proteins such as channels and carriers - movement of large or charged molecules via membrane proteins eg: ions, sucrose etc

Osmosis

The diffusion of water molecules from a lower solute to a higher solute concentration across a partially permeable membrane (PM) - movement of water molecules (dependent on solute concentration)

Hypertonic, isotonic & hypotonic

What are the three types of osmosis?

Isotonic

Having the same solute concentration as the other solution - No net movement

Hypotonic

Having a lower solute concentration relative to the other solution - Water will rush in (making the lower solute grow bigger)

Hypertonic

Having a higher solute relative to the other solution - Water will rush out (making higher solute grow smaller)

Active Transport

The process of moving substances across the plasma membrane against the concentration gradient, needs input of ATP for this task

Protein pumps, endocytosis & exocytosis

What are the three main ways of active transport?

Protein pumps

The pump uses the energy from ATP to move the substances across the plasma membrane. In this process, the pump (proteins) changes shape

Endocytosis

The active transport of macromolecules into the cell via vesicle formation, part of the PM engulfs (surrounds) the large substance, the large substance and PM is then pinches off and forms a vesicle, which is then moved into the cell

Phagocytosis

If the bulk substance is a solid = (to eat), a process where a cell engulfs and digests large particles, like bacteria or cellular debris, using its own membrane

Pinocytosis

If the bulk substance is a liquid = (to drink) a type of endocytosis where a cell takes in extracellular fluid and dissolved substances by engulfing them in small vesicles

Exocytosis

The active transport of macromolecules out of the cell by a vesicle fusing with the plasma membrane, Vesicle formed within the cell, fuses with the PM and then is released out of the cell, This process is utilised when the Golgi apparatus exports proteins and other materials out of the cell

Binary fission

A form of asexual reproduction in which the parent cells splits into two equal sized daughter cells

1st stage of binary fission

A single DNA molecule unwinds and is replicated and attaches to the membrane

2nd stage of binary fission

The cell membrane grows and doubles in size

3rd stage of binary fission

The two chromosomes are pulled apart. The plasma membrane pinches in the centre

4th stage of binary fission

Two identical daughter cells are produced

Asexual reproduction

A type of reproduction where a single parent produces without the fusion of gametes (sperm and egg)

Advantages of asexual reproduction

• Only 1 cell is required to make 2 cells

• It is a rapid process

Disadvantages of asexual reproduction

• The daughter cells are genetically identical

• The species is more susceptible to environmental changes

Prokaryotic cells

What cells would use binary fission?

Eukaryotic cells

What cells would use mitosis?

Cell Cycle (Mitosis)

The process of a cell growing, dividing and dying, The organised division of the nucleus

Interphase

The phase cells exist in majority of the time when they are not dividing

G1 Phase

The longest phase of the cell cycle. During this phase, the cell becomes larger and synthesises proteins and organelles

S Phase

The cell replicates it’s DNA by copying each strand of chromatin

G2 Phase

The cell grows rapidly for the start of mitosis

Checkpoint

Exist at various stages of the cell cycle to guard against damaged cells replicating

G1 checkpoint

Cells assesses the health of it’s organelles

G0 checkpoint

Cells exit further replication if it is not fit to continue

G2 checkpoint

Cells assesses if the DNA strands have replicated correctly before proceeding

Prophase

Replicated DNA coils into chromosomes

Metaphase

Chromosomes move to the centre of the cell

Anaphase

Chromosomes seperate at the centromere and move to the opposite sides of the cell

Telophase

The chromosomes begin to unravel and a new nuclear membrane forms around the DNA at seperate ends of the cells

Cytokinesis

The end of mitosis where the cell splits to form two identical daughter cells

Apoptosis

Naturally programmed cell death

Intrinsic pathway

A biochemical pathway occuring completely within a cell that triggers apoptosis, Internal signals (stress from inside the cell)

• DNA damage

• Lack of growth factors

• Oxidative stress

• Cell injury or aging

Extrinsic pathway

Apoptosis initiated by an external signal binding to a death receptor. External signals (coming from outside the cell)

• Binding of a death ligand (e.g., FasL, TNF) to a death receptor (e.g., Fas, TNFR) on the cell membrane.

1st stage of apoptosis

A series of enzymes called caspases are activated and start to break down the cytoskeleton of the cell

2nd stage of apoptosis

The cell starts to shrink

3rd stage of apoptosis

DNA is broken down

4th stage of apoptosis

The cell membrane forms into small bulges called blebs

5th stage of apoptosis

The blebs break off from the cell to form apoptopic bodies

Necrosis

Unplanned cell death as a result of injury to the cell

• Cell bursts and spills contents

• Causes inflammation in the body

Cancer

A disease caused when cells divide uncontrollably and spread into surrounding tissues

Mutagen

Any agent that causes permanent damage to the DNA of a cell

• This causes a genetic mutation which is a change that occurs in our DNA code

Stem cells

A cell that is capable of forming different cell types

Embryonic stem cells

Cells found in an embryo that can become any type of specialised cell and endlessly reproduce

• These are found in the embryo

• They can become any specialised cell in the body

Adult stem cells

Cells that can reproduce themselves or produce daughter cells that can become more than one cell type

Totipotent stem cells

An undifferentiated cell that can later differentiate into any type of cell

• These can differentiate into any cell in the organism

• They are only found in early cells of the embryo, from the zygote

• They can be come “totally anything”

Pluripotent stem cells

A stem cell that can differentiate into any cell type within a broad group

• The inner cell mass of the blastula is pluripotent

• These stem cells can differentiate into most of the cells in multicellular organisms, except placenta cells

• Can become “pretty much anything”

Multipotent stem cells

A stem cell that can only differentiate into a limited number of closely related cells

• They have limited ability to produce different cell types, eg. the stem cells in bone marrow can produce red blood cells, white blood cells and platelets, but they cannot produce other types of cells

Unipotent stem cells

A stem cell that can only form one cell type

• These are the most common type of stem cells in the human body

• These type of cells can only be used for the regenerated as a stem cell

• They are “unique”

Totipotent, pluripotent, multipotent & unipotent

What is the correct order for hierarchy of cell potency

Organism, systems, organs, tissues & specialised cells

What is the correct order for hierarchy of organisation