Cell Biology B1

Vocabulary-based flashcards covering cell specialization, structure, cell division, transport mechanisms, and microscopy based on lecture notes.

Neurons (nerve cell)

Cells that carry electrical impulses (messages) in one direction to different body parts; they are long and thin.

Red Blood Cells

Cells that carry oxygen from the lungs to the rest of the body; they contain hemoglobin, have a small diameter, a large surface area, and no nucleus.

Muscle cells

Elongated cells containing many mitochondria that contract to allow movement.

Sperm Cells

Cells that swim to an egg to fertilize it; they feature a large nucleus, digestive enzymes, many mitochondria, and a long tail.

Gland cells

Large cells that lie next to blood capillaries and are able to produce and release chemicals such as hormones.

Egg Cells

The target for sperm in fertilization; characterized by a large diameter, stored food, and a large nucleus.

Fat Cells

Cells providing energy storage that contain little cytoplasm and few mitochondria, with the ability to expand to $1000 \times$ their size.

Cell differentiation

The process where cells become specialized for different functions.

Specialised cells

They are cells that are designed to carry out a particular role in the body

Animal cell structure

Nucleus, cytoplasm, mitochondria, ribosomes and cell membrane

Plant cell structure

Nucleus, cytoplasm, mitochondria, ribosomes, cell membrane, permenant vacuole, chloroplasts and cell wall

Bacteria cell structure

Cytoplasm, ribosomes, cell wall, circular strand of DNA and plasmids

Magnification

The process of making an object appear bigger, calculated as Image size/ Actual size

Resolution

The ability to distinguish between 2 points, giving a sharper image.

Light Microscope

Cheap, easy to use, poor resolution and cannot see sub-cellular structures.

Electron Microscope

High-resolution, see sub-cellular structures, is expensive and hard to use.

Eukaryotic Cells

Complex cells, such as animal and plant cells, that contain a nucleus and other membrane-bound organelles like chloroplasts or mitochondria. Much larger than prokaryotic cells.

Prokaryotic Cells

Simple cells, such as bacteria, that lack a nucleus and other membrane-bound organelles. Much smaller than eukaryotic cells.

Root hair cell

A specialised plant cell that absorbs water and dissolved minerals from the soil; it contains a large permanent vacuole (speeds up movement water), increased surface area (increase speed water absorption) and many mitochondria (transfer energy for active transport of mineral ions).

Palisade Photosynthetic cell

Carries out photosynthesis that is column-shaped and moveable chloroplasts positioned to maximise sunlight absorption.

Xylem

Hollow tubes that transport water and mineral ions from the root to the leaves; they are strengthened by lignin spirals and rings to withstand water pressure.

Phloem

A transport system for glucose and amino acids; it has sieve plates for free movement of nutrients, simple structures for easier movement of nutrients and companion cells with mitochondria to provide energy to transport substances in and out of sieve.

Mitosis

The process where (usually multi-cellular organisms) cells divide to produce new identical daughter cells for growth, repair, and development. (can be for reproduction as well if uni-cellular organism like yeast)

Binary Fission

Prokaryotic cells like bacteria (uni-cellular) divide by binary fission as they have no linear chromosomes or nucleus for reproduction only.

Binary fission stages

1) Cell increases in size and replicates genetic material of plasmids and circular strand of DNA

2) Genetic material pulled to each end of cell

3) Cytoplasm divides and new cell wall forms to create two identical daughter cells (has different number of plasmids)

Cell Cycle Stage 1 (Interphase)

The stage where the cell grows, increases sub-cellular structures, and DNA doubles to form 2 copies of each chromosome.

Cell Cycle Stage 2 (Mitosis)

One set of chromosomes is pulled to each end of the cell and the nucleus divides.

Cell Cycle Stage 3 (cytokinesis)

Cytoplasm and cell membrane divide to form $2$ identical cells.

Stem Cells

Unspecialised cells with the ability to specialise when required and self-regenerate (divide by mitosis) types include Embryonic and Adult.

Embryonic stem cells

Adv: Differentiate any type of specialised cell to treat wide variety of diseases, Using them instead of wasting them (IVF left overs)

Disadv: Ethical issues (people think wrong to destroy embryo), Uncontrolled growth, may be rejected from immune system, Could be contaminated with Virus

Adult stem cells

Adv: No ethical issues, Not rejected from persons body (as comes from own bone marrow)

Disadv: Only differentiate into specialised blood cells to treat few types of diseases, operation hazards e.g infection

Meristem Tissue

Stem cell tissue in plants found at the tips of roots and shoots that can develop into any type of plant tissue.

Diffusion

The passive movement (spreading out) of particles from an area of high concentration to low concentration down the concentration gradient.

Factors that increase the rate (speed) of diffusion

Steeper the concentration gradient

Larger the surface area

Smaller the molecule size

Increase temperature (more energy for faster movement)

Exchange surfaces

Single-celled organisms have a large surface area: volume ratio whilst Multi-cellular organisms have a smaller surface area: volume ratio. The SA:V decreases as an organism gets larger.

Multi-cellular organisms specialised for material exchange (Alveoli, Gills, Villi, Root hair cell, leaves)

Large surface area

Very thin (short diffusion distance)

Exchange surface is permeable to substance needs exchanged

Good supply of external medium (02/C02) to maintain concentration gradient

Good supply of blood (internal medium only animals) maintain concentration gradient

Moist lining (alveoli, gills + leaf) allow gases dissolved before diffusing across membrane

Osmosis

The movement of water from a high concentration to low concentration through a partially permeable membrane down the concentration gradient.

Isotonic Solution

A solution with equal solute concentration where water moves in and out of the cell evenly, keeping it stable and remain shape.

Hypertonic Solution

A solution with a lower water concentration outside (more solute) than the inside of the cell, causing water to flow out and the cell to shrink/shrivel.

Hypotonic Solution

A solution with a higher water concentration outside (less solute) than the inside of the cell, causing water to flow in and cell can swell or burst.

Active Transport

An active process that moves particles from a low concentration to a high concentration across a cell membrane, against the gradient, requiring energy released from respiration.