bioogy 1 unit 1 cell biolgy correct

Formula for magnification and rule

Magnification= image size /real object size

Rule- Both image and object size should have the same unit which is mm

What are micrometres used to measure?

What is the symbol and size?

Size of cells

1 micrometre = 1 millionth of a metre

• Symbol: μm

• 1 μm = 0.000001 m = 10⁻⁶ m

what are nanometres used to measure? What is the symbol and size?

Measure stuff inside the cell

1 nanometre = 1 billionth of a metre

• Symbol: nm

• 1 nm = 0.000000001 m = 10⁻⁹ m

Differentiation

Process of which a cell changes to become specialised for its job

(Specialisation is a specialised cell, differentiation is the process of it becoming specialised)

Examples of specialised cells

Muscle cells

Sperm cells

Nerve cells

Root hair cells

Xylem cells

Phloem cells

(Know the job and adaptations of each one)

Stem cells

An unspecialised cell that can divide to produce more stem cells or differentiate into other types of specialised cells.

(Know fors and against for stem cells)

With stem cells transplant, what is there always a risk off?

Infection or virus

Therapeutic cloning

Is when an embryo is produced with the same genes as the patients

This means stem cells from embryos can be transplanted into the stem cells of the patient without being rejected by the immune system

Once inside the patient the stem cells can differentiate. It can replace cells tha stopped working correctly

Chromosomes

Coiled up lengths of DNA molecules

Cell cycle process and its purpose?

The series of stages a cell goes through to grow, replicate its DNA, and divide to produce new cells.

Purpose

1-Growth – It allows the organism to grow by making more cells.

2-Repair – It replaces damaged or dead cells.

3- Development – It helps tissues and organs develop properly.

4- Replacement – It ensures old cells are replaced to keep the body healthy.

List all the stages of the cell cycle process (long and a bit hard)

Stage 1: Interphase- Cells grow and the cell copies its DNA (so each chromosome is duplicated). Energy is stored ready for cell division.

Stage 2-Mitosis (cell division) Four different phases: Phase 1, chromosomes get shorter and the nucleus disappears. Phase 2, chromosomes line up in the middle. Phase 3, the chromosomes are pulled apart, one chromatid (one of the two identical copies of a chromosome before the cell divides) goes to each side of the cell.Phase 4, a new nucleus forms at each end. The cell now has two identical nuclei.

Stage 3- Cytoplasm and cell membranes divides. It produces two identical cells

Diffusion

The spreading of particles, along the concentration gradient, from a high concentration to a low concentration.

What things affect rate of diffusion

Temperate- increase tem means faster rate of diffusion

Concentration gradient- The bigger the concentration gradient the faster the diffusion rate

Surface area- The larger the surface area, the larger the diffusion

Osmosis

Osmosis is the movement of water molecules, across a partially permeable membrane, from a region of high water concentration to a region of low water concentration.

Partial permeable membrane

Partially permeable membranes allow some molecules to pass through but not all molecules, example, not sugar molecules.

Turgid

Turgid means when a plant cell is swollen with water (because of osmosis) and expands a lot. The cell wall prevents it from bursting

Flaccid

Flaccid is when the cell in a plant shrinks because of loss of water. This only happens when you put the plant cell in a concentrated solution.

A concentrated solution is: A solution that has a lot of solute (like sugar or salt) dissolved in a certain amount of solvent (like water).

Active transport

Active transport is when cells use energy to transport substances from a low concentration to a high concentration, going against the concentration gradient.

Give 3 places where active transport is found

1- Small intestines

2- Root hair cells

3- Kidneys

Plants use magnesium for …

Colour

Why does surface area and volume ratio matter?

It matters because

. A large SA:V ratio, means diffusion happens quickly

.Small SA:V ratio, diffusion is slow

What are some adaptations to maximise the effectiveness of exchanging substances

1-They have a thin membrane, so substances only have a short distance to diffuse

2- They have a large surface area so lots of substances can dissolve at once

To do the lungs job, what does it need…

Alveoli’s

Alveoli’s

Tiny air sacs found in the lungs and is where gas exchange takes place

Adaptations of alveoli’s/

1-An enormous surface area

2- Very thin walls

3- A good blood supply

Capillaries and function

Are tiny blood vessels that carries blood very close to the alveoli’s, so the gas can diffuse quickly. It also brings in oxygenated blood and takes out deoxygenated blood.

Villi

Tiny finger like shapes in the small intestine that helps take in nutrients

Adaptations for villi?

1-They have a very large surface area, so food ca be absorbed much more quickly into the blood

2- A very good blood supply (to assist quick absorption)

3- A single layer of surface cells

Stomata and job and adaptation

Stomata are tiny openings underneath the surface of the leaves that allow gas exchange to happen. They let carbon dioxide in, and oxygen and water vapour out. Each stomata is surrounded by guard cells, which control its size. The guard cells close the stomata if the plant is losing water faster than it can be replaced.

Adaptations of the leaves?

The flatten shape of the leaf increases the area of this exchange surface

It hast tiny holes called stomata underneath the surface of the leave where CO2 diffuses in AND oxygen and water vapour diffuses out

The structure of the leaves lets ……..

gasses diffuse in and out of the cell

Explain the fishes the gas exchange in the fishes gill

The gills are the gas exchange surface in fish.

Water (containing oxygen) enters the fish through its mouth and passes to the gills. As this happens, oxygen diffuses from the water into the blood in the gills and carbon dioxide diffuses from the blood into the water.

What are the gills in fish made out of and what is it’s purpose?

The gills are made out from filaments, which increase the surface area

Why do plants need mineral ions?

For growth

Explain why plants are not able to rely on diffusion to absorb mineral ions from the soil.

Because the concentration of minerals is higher inside the plant than in the soil, so diffusion will lead to less minerals inside the plant.

State two ways in which active transport differs from diffusion?

1- Active transport goes against a concentration gradient, whereas diffusion doesn’t.

2- Active transport requires respiration to do its job; diffusion doesn’t.

Give four features of an effective gas exchange surface in an animal:

A large surface area

good blood supply

thin membrane

being ventilated, which means air constantly breathes in and out.